Bhagya

Field Visit Question Answer Class 10 Geography Chapter 1 Maharashtra Board

February 7, 2025February 6, 2025 by Bhagya

Balbharti Maharashtra State Board Class 10 Geography Solutions Chapter 1 Field Visit Notes, Textbook Exercise Important Questions and Answers.

Std 10 Geography Chapter 1 Question Answer Field Visit Maharashtra Board

Class 10 Geography Chapter 1 Field Visit Question Answer Maharashtra Board

Geography Class 10 Chapter 1 Question Answer Maharashtra Board

Answer in short :

Field Visit Geography Class 10 Questions And Answers Question 1.
Make a report on your field visit.
OR
On the basis of which points will you write the tour report?
Answer:
The following points should be used for preparing a report.

Introduction
Location and route map
Physiographic features
Climate
Plant and animal life
Human settlements
Occupations
Land use and type of crops
Important historical places
Environmental problems and measures
Conclusion
Use of diagrams, graphs, pictures can be taken to support the information collected during the field visit.

Field Visit Geography Class 10 Question 2.
Prepare a questionnaire for a field visit to a factory.
Answer:
A questionnaire for a field visit to a factory will be as follows:

What is the name of the factory?
What is the location of the factory?
Which product is manufactured in the factory?
What are the raw materials used to make the final goods?
Where do the raw materials come from?
In which market is the final product sold?
How many people are employed in the factory?
Do you have shifts for your employees? What are their timings?
What safety measures do you adopt for your staff?
What precautions have been taken to prevent a fire hazard?
What precautions have been taken to prevent or reduce environmental pollution?
What mode of transport is used for the movement of raw materials and finished goods?

Question 3.
What items will you take with you for the field visit?
Answer:
We will take the following items with us for the field visit:

Notebook, pen, pencil, camera, binoculars, etc to collect information.
Magnetic compass, GPS enabled mobile phone and also maps to know directions and locate various places.
I-card, water bottle, cap, and a first aid box are a must.
Ziplock bag for collecting samples.
Carry a questionnaire and information booklet about the place to be visited.
Carry some bags to discard any trash.

Question 4.
Outline the importance of a field visit.
OR
Explain with examples of how field visits increase geographical knowledge.
Answer:
(i) Geography is a science to be learnt through observation.
(ii) Field study gives us an opportunity to get firsthand information of the new place having a different location, climate and landforms.
(iii) Students learn the relationship between physical and cultural factors and how man adapts himself accordingly.
(iv) They get an opportunity to interact with the local people, know about their culture, food, clothing and understand their problems.
(v) Students develop the feeling of belonging to these regions and their skill of observation and reasoning also improves.

Class 10 Geography Chapter 1 Field Visit InText Questions and Answers

Short Answers:

Question 1.
Correlate pulse cropping with low rainfall.
Answer:
(i) Extreme weather events during growing and harvesting seasons can cause serious damage to crops.
(ii) Pulses are very sensitive to torrential rain, especially in the early vegetative stage and flowering stage.
(iii) A high quantity of rainfall can cause disease infestation in crops.
Hence, pulses are grown in places where there is less to moderate rainfall.

Question 2.
Do you agree that regions and necessities influence the difference in the means of livelihood?
Answer:
(i) A person’s livelihood refers to their “means of securing the basic necessities of – food, water, shelter and clothing – of life.”
(ii) To acquire above necessities, people work either individually or as a group by using skills (both human and material) for meeting the requirements of the self. The activities are usually carried out repeatedly.
(iii) For instance, a fisherman’s livelihood depends on the availability and accessibility of fish and depending on this, primary, secondary and tertiary occupations will develop, like making of boats, nets, fish canning, transportation, etc.
(iv) So, definitely the regions and necessities influence the difference in the means of livelihood.

Question 3.
Give geographical reasons:
It is important to manage the waste during field visit.
Answer:
(i) It is our social responsibility to ensure that the cleanliness and sanctity, of the place of visit is maintained during the visit.
(ii) Managing environment also shows how responsible we are.
(iii) Managing environment assists in the prevention of the environmental pollution.

Question 4.
If you were a part of a field visit, what preparations would you make?
OR
Suppose teachers ask you to plan the visit. How will you plan the details of the trip?
If you were a part of a field visit, what preparations would you make?
OR
Suppose teachers ask you to plan the visit. How will ,you plan the details of the trip?
Answer:
Following preparations / plans will be made for the field visit:
(i) Deciding the place : Deciding an appropriate place for the field visit, selecting the means of transportation, and duration of the field visit should be planned well ahead.
e.g. selecting a place like fort/ factory/ hill station, etc.

(ii) Deciding the purpose : Deciding the objectives of the field visit and the elements which will be observed in the field visit should be decided, e.g. visiting a village to understand the problems faced by rural people in their daily life and finding solutions.

(iii) Collecting important documents : Collecting important documents like the location map, permission letters, etc.
e.g. For a visit to a factory, permission letter of the factory owner is required.

(iv) Preparing for emergencies : Preparing for emergencies is very important.
e.g. carrying first – aid kit, GPS enabled mobile phone, dry snacks, water bottle, etc.

(v) Preparing the budget: With the help of a teacher make a budget and plan the travel, stay and food expenses.

(vi) Planning the journey : Study the location map and the route map of the place to be visited. Distance, transport route should be planned. Also plan the time of departure and the entire schedule of the visit.

(vii) Making a list of items required : Water bottle, dry snacks, book, pen, binoculars, compass, camera, etc.

Question 5.
What precautions will you take continuously during the field visit?
Answer:
(i) Strictly obey instructions given by teachers.
(ii) Ensure safety of oneself and others, carry first – aid box, identity cards, etc. for emergency.
(iii) Note down information gathered immediately in the book and preserve the book and samples collected carefully.
(iv) Take photographs of sites / people wherever necessary during the field visit.
(v) Safeguard the natural surroundings and the historical monuments during the visit.
(vi) Do not litter and cause any inconvenience or harm to anybody.

Question 6.
Collect more information about mud and wood houses. (Dhabyachi ghare)
Answer:
(i) Dhabyachi ghare or mud and wood houses are made of earth mixed with water and organic materials such as straw or dung. The roof is made up of wood.
(ii) Straw is useful in binding the brick together and allowing the brick to dry evenly, thereby preventing cracking due to uneven shrinkage through the brick. Dung offers the same advantage.
(iii) These houses are built in the low rainfall areas of Maharashtra e.g. Vidarbha, Marathwada.

Question 7.
Obtain information regarding Multi-purpose Projects.
Answer:
(i) Projects which serve more than one purpose are called as Multipurpose Projects.
(ii) Multi purpose Projects are planned for various purposes like irrigation and hydropower generation, water supply for drinking and industrial purpose, flood control, navigation etc.
(iii) For e.g. Bhakra Nangal Multipurpose Project on River Sutlej, Jayakwadi Multipurpose Project on River Godavari, etc.

Question 8.
‘Vegetation is an indicator of difference in precipitation’. What are the other indicators of difference in precipitation?
Answer:
(i) Crops grown in a particular region can be one of the indicators of precipitation.

(ii) The type of houses found in the region is an indicator of precipitation. For e.g. in low rainfall regions, flat roof houses are found whereas in heavy rainfall regions houses have slanting roofs.

(iii) Texture and colour of the soil, humidity in the air, etc. are indicators of precipitation.

(iv) As temperatures rises, more people will need to keep cool by using air conditioner, which uses a lot of electricity. So, consumption of energy is another indicator of precipitation.

(v) Animal life can also be affected. If the climate is not suitable – (too wet, too dry, or too cold in winter) – plants and the animals that depend upon them for food or habitat will struggle or die.

Question 9.
How will the terrain below appear to the birds from the sky?
Answer:
(i) To the birds flying in the sky, the terrain will look like a flat land.
(ii) Every object on the terrain will look very small in size.

Question 10.
Out of which process has the plateau of Maharashtra formed? What is the main type of rock seen here?
Answer:
(i) The Deccan Plateau was formed due to volcanic eruptions.
(ii) The Deccan Plateau is made up of basalt rock.

Question 11.
Guess in which season of the year is the field visit being undertaken?
Answer:
The following points tell us that the field visit is being undertaken in the rainy season.
(i) Paddy fields are visible.
(ii) Waterfalls are seen in the Sahyadris.

Question 12.
What is the concept of ‘Devrai’?
Answer:

Devrai means sacred groves / patch of forest.
In Maharashtra small patches of forest in the Ghats are protected by local people.
It is based on the understanding that all creations of nature have to be protected. Such beliefs have preserved several virgin forests in pristine form.
These patches of forests or parts of large forests have been left untouched by the local people and any interference with them is banned.

Question 13.
What precautions have to be taken while going to the sea coast?
Answer:
The following precautions must be taken while going to the sea coast:

Sun exposure at the sea is quite high. So, bring sunglasses and a hat to beat the sun’s rays and prevent sunburn.
Consult the local people before entering the sea water.
Avoid going beaches if there’s lightning in the forecast.
Don’t go in deep water, if you do not know to swim.
Beware of the waves, some are more powerful than you think.
Don’t climb edges of rocks to click photographs, as they may be slippery.
Be sure to bring plenty of water.
Do not wear expensive watches and jewellery when going to the sea coast.

Question 14.
What is the simplest method of understanding the timings of the tides?
Answer:

Tides are defined as the rise and fall of sea levels, caused by the combined effects of gravitational forces of the Moon, the Sun and the rotation of Earth.
The simplest method of understanding the timings of the tides is by asking the local people.
One can also do the same through observation, This tidal range typically changes twice daily.
Since the lunar high tides occur every 12 hours and 25 minutes, which means that it takes 6 hours and 12.5 minutes to go from high tide to low tide or vice versa.

Question 15.
What type of photographs will you click with respect to the field visit?
Answer:

The type of photographs to be clicked will depend on the purpose and place to visit.
If the purpose of field visit is to study landforms then we will click pictures of mountains slopes, plateaus and plains.
If the purpose of the visit is to study a forest, then we will click pictures of vegetation, dominant trees, wild animals, etc.
Similarly, if we are visiting a village it would be settlements, agricultural fields, roads, irrigation, schools, etc.

Class 10 Geography Chapter 1 Field Visit Additional Important Questions and Answers

Short Answers:

Question 1.
It is necessary to take items required for field visit and the questionnaires along with us.
Answer:
(i) We need to carry various items for field visit.
(ii) For e.g. – A camera is required for clicking photographs, GPS enabled mobile phone and also maps to know directions and locate various places.
(iii) Questionnaire helps to collect the information. So, it is necessary to take items required for field visit and the questionnaires along with us.

Question 2.
Prepare a questionnaire of atleast 8 questions with an aim to visit the meteorological department.
Answer:
(i) How many departments are there in the Meteorological office?
(ii) What is the role of each department?
(iii) How and when is the maximum and minimum temperature measured?
(iv) Which instrument is used to measure rainfall?
(v) How do satellites play an important role in the weather forecast?
(vi) Are drones used by the meteorological department?
(vii) What are the total number of employees?
(viii) Are all the weather forecasts accurate?

Question 3.
What steps will you take to manage the litter during field visit?
Answer:
(i) During a field visit, we must ensure that we do not throw litter out of the window while travelling and also we do not throw any trash or litter around us.
(ii) We must use the dustbins for throwing empty j packets of snacks, empty water bottles, left-over food items, etc.
(iii) Also one must try to keep the surroundings clean by segregating wet and dry waste.
(iv) We can also avoid usage of plastic bags and instead, can make use of jute or cloth bags. Following discipline is very important during a field visit.

10th Std Geography Questions And Answers:

Economy and Occupations Question Answer Class 10 Geography Chapter 8 Maharashtra Board

February 7, 2025February 6, 2025 by Bhagya

Balbharti Maharashtra State Board Class 10 Geography Solutions Chapter 8 Economy and Occupations Notes, Textbook Exercise Important Questions and Answers.

Std 10 Geography Chapter 8 Question Answer Economy and Occupations Maharashtra Board

Class 10 Geography Chapter 8 Economy and Occupations Question Answer Maharashtra Board

Geography Class 10 Chapter 8 Question Answer Maharashtra Board

1. Fill in the blank with appropriate word.

Question a.
India’s per capita income is less than Brazil due to _______.
(a) low national income
(b) massive population
(c) big family size
(d) low foodgrain production
Answer:
(b) massive population

Question b.
The economy of Brazil is mainly dependent on ______ the activities.
(a) primary
(b) secondary
(c) tertiary
(d) quaternary
Answer:
(c) tertiary

Question c.
The economics of India and Brazil are of the _____ type
(a) undeveloped
(b) developed
(c) developing
(d) highly developed
Answer:
(c) developing

2. Answer the following questions:

Question a.
Why has mining not developed in the western part of Brazil?
Answer:
(i) Most of the western part of Brazil is covered by the thick dense equatorial rainforests of the Amazon Basin.
(ii) Inaccessibility, poor transport links, unfavourable climate, heavy rainfall are the main barriers for mining in this part.
(iii) Moreover, lack of knowledge of potential reserves of resources is the other factor which has led to limitations in mining in the western part of Brazil.
(iv) Therefore, mining is not developed in the western part of Brazil.

Question b.
What are the similarities and differences in the fishing activities in Brazil and India.
Answer:
Similarities:

In Brazil and India fishing activity is developed near the coastal areas.
In both the countries, marine fishing is well- developed.

Differences:

In India, fresh water fishing is practised, whereas in Brazil due to unfavourable conditions, fresh water fishing is not developed.
The meeting of the warm Brazil current and the cold Falkland current, off the coast of South-East Brazil makes it a good fishing ground. In India such currents do not come together but due to other favourable conditions fishing has been developed.
Major fishes of Brazil are swordfish, shrimp, lobsters and sardines.
Major fishes of India are mackerel, bombay duck, prawns, horse mackerels, clupeids, silver bellies and sardines.

3. Give reasons:

Question a.
Per capita land availability is more in Brazil as compared to India.
Answer:

India occupies 2.4% land area of the world and supports 17.5% of the world’s total population.
Brazil occupies 5.6% of land area of the world and supports only 2.75% of the world’s total population.
Average density of population in India is about 382 persons per sq. km. while average density of population in Brazil is around 23 persons per sq. km.
Thus Brazil’s population is lesser than India, but it occupies a larger land area than India.
So, the per capita land availability is more in Brazil as compared to India.

Question b.
There is mixed economy in Brazil and India.
Answer:

In a mixed economy there is a co-existence of public sector and private sector.
In Brazil, sectors like health, banking, telecommunications, railways and airways are owned and managed by both public and private sectors.
In India railways is largely a public sector whereas all the other sectors are owned and managed by both private and public sectors.
So it is said that there is a mixed economy in Brazil and India.

4. Study the following graph and analyse in short.
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 1
Answer:
(i) This is a compound bar graph showing the contribution of primary, secondary and tertiary sectors to the national income of India and Brazil.
(ii) It also shows the percentage of population engaged in these sectors.
(iii) The contribution of primary, secondary and tertiary sector to India’s national income is about 17%, 26% and 57% respectively.
(iv) Whereas the contribution of primary, secondary and tertiary sector to Brazil’s national income is about 5%, 28% and 67% respectively.
(v) The population engaged in primary, secondary and tertiary sector of India is about 49% 24% and 27% respectively.
(vi) The population engaged in primary, secondary and tertiary sector of Brazil is about 10%, 19% and 71% respectively.
(vii) Thus it is understood clearly from the graph that Brazil is not an agrarian economy like India.

Class 10 Geography Chapter 8 Economy and Occupations Intext Questions and Answers

Give It a Try

Read the following graph and answer the following questions:
Gross National Incomes (GNI) from 1960 to 2016 (in million US. $)
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 12

Question 1.
Which country’s national income was the highest in 2016 and how much was it?
Answer:
USA’s national income was highest in 2016. It was approx. U.S. $ 18000 million.

Question 2.
Comparing India and Brazil, which country had a higher national income in 1980?
Answer:
Brazil had a higher national income in 1980, as compared to India.

Question 3.
Comparing India and Brazil, which country had a higher national income in 2016?
Answer:
Comparing India and Brazil, India had a higher national income.in 2016.

Question 4.
Tell the difference between the GNP of Brazil and India in 2016.
Answer:
The difference between the GNP of Brazil and India in 2016 is approximately US $ 300 million. (India : $ 2000 million – Brazil: $ 1700 million)

Question 5.
Name the developing and developed economies based on the graph?
Answer:
India and Brazil are developing economies and the USA is a developed economy.

Question 6.
Calculate the difference between the national incomes of developed and developing countries , in 2016.
Answer:
The difference between the national incomes of developed and developing countries in 2016 was nearly U.S. $ 16500 million.
(US: $18500 million – India, Brazil: $ 2000 million)

Try this

Question 1.
A table regarding the ownership of various sectors in both the countries is given. Like Brazil, fill the details regarding India and complete the table.
Answer:

S.No	India	Sector	Brazil
(1)	Private and Public both	Banking	Private and public both
(2)	Largely Public	Railways	Private and public both
(3)	Largely Private Little Public	Airways	Private and public both
(4)	Private and Public both	Electricity production	Largely public
(5)	Private and Public both	Iron and Steel Industry	Largely public
(6)	Private and Public both	Health	Private and public both
(7)	Largely Private and Public	Education	Largely public, little private
(8)	Largely Private and little Public	Telecomm unications	Private and public both

Let’s Recall

Question 1.
Classify the following activities by ticking ( ✓ ) in the respective column
Answer:

S.No	Activities	Primary	Secondary	Tertiary
(1)	Television Broadcasting			✓
(2)	Bee-keeping	✓
(3)	Coir and Rope making	✓
(4)	Jaggery – making		✓
(5)	Producing blades of the plough		✓
(6)	Construction		✓
(7)	Extracting Iron Ore	✓
(8)	Automobile Production		✓
(9)	Rice Production	✓
(10)	Teaching			✓
(11)	Driving buses			✓
(12)	Providing lodging and boarding facilities			✓

Question 2.
Name the warm and cold ocean currents near the Brazilian coast.
Answer:
Warm ocean current: Brazil current Cold ocean current: Falkland current

Question 3.
Read the following table and answer the following questions.

Export, Import and Balance of Trade (Value in US $)
	India		Brazil
Year	Exports	Imports	Exports	Imports
2009-10	178751.4	288372.9	152994.7	127647.3
2010-11	251136	369770	197356.4	180458.8
2011-12	304623.53	489181.3	256038.7	226243.4
2012-13	214099.8,	361271.9	242579.8	223749.1

Question (1).
What is balance of trade?
Answer:
Balance of trade is the difference between the value of a nation’s exports and imports for a certain period.

Question (2).
Tell the types of balance of trades.
Answer:
There are three types of balance of trade they are as follows:

Unfavourable balance of trade: The value of imports is more than the value of exports.
Favourable balance of trade: The value of exports is more than the value of imports.
Balanced trade: The value of exports and imports is almost the same.

Question (3).
In which country do export exceed the imports in all the years?
Answer:
In Brazil, export exceeds the import in all the years.

Question (4).
Brazil’s balance of trade belongs to which type?
Answer:
Brazil has a ‘favourable balance of trade’ or ‘surplus trade’.

Question (5).
India’s balance of trade belongs to which type?
Answer:
India has an ‘unfavourable balance of trade’ or ’trade deficit’.

Question 4.
With the help of the pie chart given in Fig. , mention what is the contribution of secondary activities in Brazil’s GDP is.
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 2
Answer:
The secondary activities contribute 27.5% in Brazil’s GDP.

Activity:

Question 1.
Look at the pie-charts carefully and answer the following questions:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 2

Question (1).
Which country has a higher percentage of population engaged in primary activities?
Answer:
India has a higher percentage of population engaged in primary activities (48.8%).

Question (2).
In which country is the contribution of tertiary sector greater in the GDP?
Answer:
The contribution of tertiary sector is greater in Brazil’s GDP (67%).

Question (3).
In which country is the share of secondary activities more in the GDP?
Answer:
The contribution of secondary activities is more in Brazil’s GDP (27.5%).

Question (4).
Can we say that Brazil is an agrarian economy like India? Give reasons.
Answer:
(i) Brazil is not an agrarian economy like India.
(ii) This is because 71% of its population is engaged in the tertiary sector and it contributes 67% in GDP.

Question 2.
Use the following table and make a polyline graph with the help of computer

Country Name/Year	1960	1980	2000	2016
Brazil	240	2010	3060	8840
India	90	280	450	1680
USA	3250	14230	37470	56280

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 3

Question 3.
Observe the map of Mining and answer the following questions:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 29

Question (1)
Prepare a table of mining products and regions of production in Brazil.
Answer:

Mining products	Regions of production in Brazil
Manganese	North, east
Bauxite	Coastal region
Iron-Ore	Central, south-east
Coal	South

Question (2)
In which part of Brazil has mining activity not developed? What could be the reasons?
Answer:
Mining activity has not developed in the western part of Brazil.

Question (3)
Considering the availability of resources, where has the development of industries occurred?
Answer:
Considering the availability of resources development has occurred mainly in the coastal regions of north-east and south-east of Brazil.

Question 4.
Observe the map of Fishing and answer the following questions:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 29

Question (1)
Can you give two reasons for concentration of fishing near the south-eastern coast of Brazil?
Answer:
Fishing is done on a large scale near the south-eastern coast of Brazil as it is the region where the warm Brazil current and the cold Falkland current meet making the conditions favourable for it to develop as a good fishing ground.

Question (2)
Inland fishing is not developed in Brazil though there are large number of rivers in Brazil. Can you think of a reason?
Answer:
(i) The Amazon River Basin is very vast with a dense growth of equatorial forests, making it largely inaccessible.
(ii) The methods of inland fishing followed are quite traditional and primitive.
These are some of the reasons why inland fishing is not developed in Brazil, though there are large number of rivers.

Question 5.
Observe the logos given and answer the questions.
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 13

Question (1)
Identify the industries with which they are associated.
Answer:
(i) Oil and Natural Gas Corporation – Oil and natural gas exploration and production .
(ii) Rashtriya Ispat Nigam Ltd. (RINL) – Steel production.
(iii) Aarey – Dairy and dairy products.
(iv) Chittaranjan Locomotive Works (CLW) – Electric locomotive manufacturing.
(v) Maharashtra Agro Industries Development Corporation (Limited) MAIDC – Production of pesticides, fertilizers, animal feed, agro-engineering (introducing new kinds of farm implements, sale and repair of tractors, harvesters etc.) and processing food (like jams, jellies and sauces).
(vi) Khadi and Village industries Commission
(KVIC)-Establishment and development of khadi and village Industries in rural areas.
(vii) Central Silk Board (CSB) – Silk production.
(viii) Rashtriya Chemical and Fertilizers Ltd. (RCF) Chemical and fertilizer production

Question (2)
Which raw material is used for these industries. Classify them accordingly.
Answer:

Classification	Industries	Raw materials
Agro-based industries	Maharashtra Agro-industries Development Corporation Ltd.	Seeds, raw materials required for the production of pesticides, fertilisers
Agro-based industries	Khadiand Village Industries Commission	Cotton, silk and wool
Animal product – based industries	Aarey	Milk
Animal product – based industries	Central Silk . Board (CSB)	Silk
Minerals and metal-based industries	Oil and Natural Gas Corporation Limited (ONGC)	Crude oil and natural gas
	Rashtriya Ispat Nigam Ltd. (RINL)	Iron ore and coal
	Chittaranjan Locomotive Works (CLW)	Iron and steel and aluminium
	Rashtriya Chemical and Fertilizers Ltd. (RCF)	Chemicals and different minerals

Question (3)
From which part of India do they get these raw materials? Discuss and write.
Answer:
(i) Iron ore, coal, limestone etc.: Chhota Nagpur plateau area of Jharkhand, Odisha, Chhattisgarh, Bengal, Madhya Pradesh, Rajasthan, Karnataka, Goa, Maharashtra etc.
(ii) Natural Gas: Krishna-Godavari Basin.
Mumbai High, in Arabian Sea.
(iii) Mineral Oil: Mumbai High in Arabian sea, Digboi in Assam, Ankleshwar in Gujarat.
(iv) Milk: Bihar, Tamil Nadu, Haryana, Maharashtra, Punjab, Gujarat etc.
(v) Cotton: Gujarat, Maharashtra, Telangana, Karnataka, Andhra Pradesh.
(vi) Silk: Karnataka, Andhra Pradesh, Tamil Nadu, West Bengal, Jammu and Kashmir.

Think about It

Question 1.
Which type of occupations gives a boost to the development of a country’s economy?
Answer:
Secondary and tertiary occupations give a boost to the development of a country’s economy.

Make Friends With Maps

Look at the map given in Fig. The major primary occupations in Brazil are shown here. Discuss the following points and write your observations.
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 29

Question 1.
In which part of Brazil is coffee mainly produced?
Answer:
Coffee is mainly produced in the South and South-east part of Brazil.

Question 2.
Which food crops are mainly produced in Brazil?
Answer:
Rice, soyabean and corn are the food crops mainly produced in Brazil.

Question 3.
Can you relate the production of these crops with the climate there?
Answer:

Brazil has a wide range of climatic variation.
Rice requires hot and humid climate with heavy rainfall. So it is grown in the coastal region.
Corn grows well in the central parts of Brazil, because the climate there is hot and dry.

Question 4.
Where are the rubber plantations concentrated?
Answer:
The rubber plantations are concentrated in the north western part in the Amazon River Basin area.

Question 5.
Complete the table.
Answer:

Types of crops	Crops	Areas of Prodution
Food crops	Corn / Maize	Central
Food crops	Rice	coastal region
Cash crops	Coffee	South east
	Sugarcane	Central, East
	Cocoa	East
	Rubber	North
	Soyabean	South
Fruits and Vegetables	Bananas	coastal region.
Fruits and Vegetables	Oranges	East, Central

Note : Areas of the production Each one has a different area. Difficult to point out one area for all the varieties of cash crops, food crops and rice.

Use Your Brain Power

Question 1.
If Rajasthan does not have a coastal area, then how does it produce salt?
Answer:
(i) Rajasthan does not have a coastline, but it still produces salt because of the Sambhar Lake, which is India’s largest inland salt lake.
(ii) Salt is produced on a large scale here due to high proportion of salt in Sambhar Lake and high rate evaporation.

Colours Of Both

Question 1.
Indo-Brazil ties: Answer the following.

Question (1)
What does BRICS stand for?
Answer:
BRICS stands for Brazil, Russia, India, China and South Africa.

Question (2)
When was it established?
Answer:
BRIC was established in June 2006. South Africa was inducted in 2010. Then it became BRICS.

Question (3)
What are the objectives of this bloc?
Answer:
The main objectives of BRICS are:

To achieve regional development.
To act as a bridge between developed and developing countries by providing financial assistance and support in various infrastructure projects.

Question (4)
The countries of which continent are not a member of this bloc?
Answer:
The countries of North America and Australia are not a member of this bloc.

Question (5)
In which continents do the member countries lie?
Answer:
The member countries lie in the continents of Europe, South America, Africa and Asia.

Question 2.
Study the graphs and answer the following questions on
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 22

Question (1)
In which years did the value of exports to Brazil exceed the imports from Brazil?
Answer:
In the years 2008, 2010, 2011, 2013, 2014 and 2015 the value of exports to Brazil have exceeded the imports from Brazil.

Question (2)
In which year was trade with Brazil the most favourable of all?
Answer:
Trade with Brazil was most favourable in the year 2013.

Question (3)
Comment upon the Balance of Trade in the year 2013.
Answer:
(i) The value of Balance of Trade between India and Brazil was maximum in the year 2013.
(ii) Also, the Balance of Trade was in India’s favour.

Question (4)
From which year the value of exports to Brazil have exeeded the value of import from Brazil?
Answer:
From 2010 to 2015 (except 2012).

Question (5)
Write a note on the trade between Brazil and India.
Answer:
(i) Trade between India and Brazil has not been consistent.
(ii) Most of the time the trade has been favourable for India, with exports more than imports.
(iii) In 2015, India-Brazil trade has shown a downfall with both imports and exports at an all-time low.

Question (6)
In which year was the value of exports to Brazil the maximum?
Answer:
The value of exports to Brazil was the maximum in 2014.

Give It A Try

Question 1.
The following images are related to agricultural activities. Identify and write whether they are practised in Brazil or India.
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 9

Answer:
(i) In the first image, coffee plantation is seen. It is found mainly in Brazil. In India, coffee plantation are seen in the South Indian states of Karnataka, Kerala and Tamil Nadu.

(ii) The second image is of the Tea plantation. It is mainly found in India, in Assam, West Bengal, Tamil Nadu and Kerala.

(iii) In the third image, shifting agriculture is seen. It is also called ‘Slash and Burn’ agriculture. In this method, the land under forests is cleared by cutting and burning. On this patch of land, subsistence type of agriculture is practised for the next few years.

Once this patch of land loses fertility; another patch of land is brought under shifting cultivation. It is mainly practiced in Brazil and in some parts of India.

In the fourth image, paddy cultivation is seen and it is mainly practiced in India where there is heavy sufficient and irrigation rainfall.

Try This

Question 1.
Show the distribution of crops like wheat, jowar, rice, cotton, sugarcane, tea, jute, coffee and rubber, apple in the outline map of India using symbols. Name the map.
Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 11

Find Out

Question 1.
Obtain information regarding pisciculture in India with the help of internet and reference books and write a note.
Answer:

Breeding, rearing and transplantation of fish by artificial means is called pisciculture. It is also called fish farming.
Fishes are raised in tanks or enclosures for commercial reasons.
Pisciculture in India is increasing rapidly due to the increasing demand for fish and fish products.
Indian climate is suitable for practising pisciculture. Wide variety of fish species are raised in the fish farms, e.g. salmon, carp, catfish.
Due to availability of abundant labour and water sources like lakes, ponds, rivers, etc, pisciculture has become easier.
Employment opportunities are created due to pisciculture.
Banks offer loans for those interested in this business.

Class 10 Geography Chapter 8 Economy and Occupations Additional Important Questions and Answers

Choose the correct option and rewrite the statements:

Question 1.
India has a/an ________ national income as Compared to Brazil.
(a) higher
(b) lower
(c) equal
(d) very low
Answer:
(a) higher

Question 2.
In Brazil, ______ is the main occupation of the people living in the highlands and coastal areas.
(a) agriculture
(b) mining
(c) animal rearing
(d) sericulture
Answer:
(a) agriculture

Question 3.
The main cereal crops grown in Brazil are ______ and maize.
(a) wheat
(b) barley
(c) oat
(d) rice
Answer:
(d) rice

Question 4.
Production of maize is largely concentrated in the _____ part of Brazil.
(a) western
(b) northern
(c) southern
(d) central
Answer:
(d) central

Question 5.
Brazil is the largest exporter of coffee and ______ in the world.
(a) rubber
(b) cocoa
(c) soyabean
(d) maize
Answer:
(c) soyabean

Question 6.
The major states growing coffee are _______ and Sao Paulo.
(a) Rio de Janeiro
(b) Minas Gerais
(c) Para
(d) Parana
Answer:
(b) Minas Gerais

Question 7.
Coffee farms are called _____ in Brazil
(a) para
(b) fazendas
(c) Cerrado
(d) Savannah
Answer:
(b) fazendas

Question 8.
Cattle, sheep and goats are reared in the _____ of the South of Brazil.
(a) Amazon Basin
(b) Parana River basin
(c) Savannah grasslands
(d) Coastal areas
Answer:
(c) Savannah grasslands

Question 9.
The eastern part of Brazil is rich in various types of _____.
(a) crops
(b) animals
(c) minerals
(d) forests
Answer:
(c) minerals

Question 10.
Inaccessibility, lack of knowledge of ________ potential reserves, dense forests are factors which have led to limitation in in the interior parts of Brazil.
(a) agriculture
(b) mining
(c) agro- forestry
(d) fishing
Answer:
(b) mining

Question 11.
Due to the increasing demand in the country, mining has developed well in the ______ region of Brazil.
(a) coastal
(b) highland
(c) mountainous
(d) equatorial forest
Answer:
(b) highland

Question 12.
Brazil has a sea coast of around 7,400 km and excellent fishing grounds off the ____ coast.
(a) South Atlantic
(b) North Atlantic
(c) South Pacific
(d) North Pacific
Answer:
(a) South Atlantic

Question 13.
The meeting of the warm Brazil current and the cold Falkland current off the coast of South-east Brazil make it a good ______.
(a) fishing ground
(b) offshore oil rig
(c) ocean transport route
(d) fishermen’s settlement
Answer:
(a) fishing ground

Question 14.
Traditionally, in Brazil, fishing has been carried on by small groups of individual fishermen using _____ techniques and equipment.
(a) scientific
(b) modern
(c) primitive
(d) latest
Answer:
(c) primitive

Question 15.
The fish resources of the _____ river are not exploited much and fishing only takes place on a small scale.
(a) Parana
(b) Sao Francisco
(c) Paraguay
(d) Amazon
Answer:
(d) Amazon

Question 16.
Around 60% of land in India is under ________.
(a) cultivation
(b) industries
(c) forestry
(d) mining
Answer:
(a) cultivation

Question 17.
Indian agriculture is mainly _______ type.
(a) commercial
(b) mechanized
(c) subsistence
(d) extensive
Answer:
(c) subsistence

Question 18.
In the coastal areas of India, ______ forms an important part of the diet of many people.
(a) wheat
(b) fish
(c) lobsters
(d) millets
Answer:
(b) fish

Question 19.
Horse mackerels, clupeids and silver bellies are important varieties of ________
(a) crops
(b) fish
(c) millets
(d) cereals
Answer:
(b) fish

Question 20.
Among the freshwater varieties of fish, _______ is a major one.
(a) Sardines
(b) Mackerel
(c) Bombay Duck
(d) Silver Bellies Carp (Chopda)
Answer:
(d) Silver Bellies Carp (Chopda)

Question 21.
In India, the _____ plateau is a big store house of minerals.
(a) Malwa
(b) Bundelkhand
(c) Baghelkhand
(d) Chhota Nagpur
Answer:
(d) Chhota Nagpur

Question 22.
Coal is mined in ____ in Chhattisgarh and in eastern Maharashtra.
(a) Korba
(b) Cuddapah
(c) Digboi
(d) Kalol
Answer:
(a) Korba

Question 23.
Mineral oil wells are found in _____ in Assam.
(a) Korba
(b) Koyali
(c) Digboi
(d) Kalol
Answer:
(c) Digboi

Question 24.
Reserves of mineral oil and natural gas have been discovered at the mouth of the river _______.
(a) Krishna
(b) Kaveri
(c) Godavari
(d) Mahanadi
Answer:
(c) Godavari

Question 25.
Stones like marble are found in Rajasthan and Cuddapah in ______.
(a) Andhra Pradesh
(b) Arunachal Pradesh
(c) Himachal Pradesh
(d) Uttar Pradesh
Answer:
(a) Andhra Pradesh

Question 26.
Traditionally, the poorest part of Brazil is the ______.
(a) north-east
(b) south
(c) north-west
(d) central
Answer:
(a) north-east

Question 27.
The north-eastern part of the Indian Peninsula has a very high concentration of _____ industries.
(a) chemical
(b) metallurgical
(c) canning
(d) fruit processing
Answer:
(b) metallurgical

Question 28.
The coastal belt of _______ has a heavy concentration of coir, copra and fish canning industries.
(a) Kerala
(b) Goa
(c) Karnataka
(d) Maharashtra
Answer:
(a) Kerala

Question 29.
Many refineries are situated close to the petroleum producing areas whereas Mathura and _______ refineries are in the interior, away from the oil producing areas.
(a) Digboi
(b) Bongaigaon
(c) Barauni
(d) Koyali
Answer:
(c) Barauni

Question 30.
Among the minerals, Brazil mainly exports _____.
(a) coal
(b) gold
(c) iron ore
(d) manganese
Answer:
(c) iron ore

Question 31.
The main trading partner of Brazil among the Gulf countries is _______.
(a) Bahrain
(b) Saudi Arabia
(c) Kuwait
(d) Iran
Answer:
(b) Saudi Arabia

Question 32.
India’s major trading partners from the continent of Europe are the UK and _______.
(a) Italy
(b) France
(c) Germany
(d) Greece
Answer:
(c) Germany

Match the columns:

Question 1.

S.No	Column ‘A’	Column ‘B’
(1)	Rice and maize	(a) Commercial crops of Brazil
(2)	Tea and mangoes	(b) Cereal crops of Brazil
(3)	Cotton and jute	(c) India’s imports
(4)	Coffee, cocoa, rubber,soyabean	(d) India’s exports (e) India’s cash crops

Answer:
1 – b
2 – d
3 – e

Question 2.

Column ‘A’	Column ‘B’
(1) Kachchh	(a) Kerala
(2) Coromandal coast	(b) North east India
(3) Malabar coast	(c) Near Maharashtra
(4) Mumbai High	(d) South east India (e) Western coast

Answer:
1 – e
2 – d
3 – a
4 – c

Question 3.

Column ‘A’	Column ’B’	Column ‘C’
(1) Coal	(a) Digboi	(i) Andhra Pradesh
(2) Mineral oil well	(b) Coastal belt	(ii) Chhattisgarh
(3) Stones	(c) Korba	(iii) Kaveri
(4) Mineral oil and Natural gas	(d) River mouth	(iv) Assam
(5) Coir and copra	(e) Cuddapah	(v) Godavari
	(f) Estuary	(vi) Kerala

Answer:
1 – c – ii
2 – a – iv
3 – e – i
4 – d – v
5 – b – vi

Question 4.

Column ‘A’	Column ‘B’
(1) Coir, copra and fish canning	(a) Mathura
(2) Salt	(b) Gujarat
(3) Oil refineries	(c) Kerala
(4) Stones	(d) Barauni
	(e) Andhra Pradesh

Answer:
1 – c
2 – b
3 – d
4 – e

Answer the following in one sentence:

Question 1.
Which currency is mainly used for international trade?
Answer:
US dollar is the currency which is mainly used for international trade.

Question 2.
Name the sectors of Brazil in which Indian companies have invested money.
Answer:
Information technology, pharmaceuticals, energy, agro-business, mining, engineering, automobiles, etc. are the sectors of Brazil in which Indian companies have invested money.

Question 3.
Name the sectors of India in which Brazilian companies have invested money.
Answer:
Automobiles, information technology, mining, energy, bio-fuel, footwear, etc. are the sectors of India in which Brazilian companies have invested capital.

Question 4.
Which type of occupations give a boost to the development of a country’s economy ?
Answer:
Tertiary occupation give a boost to the development of a country’s economy.

Name the following:

Question 1.
Factors making it possible for growing a variety of crops in Brazil.
Answer:
Favourable climate and topography.

Question 2.
The main cereal crops of Brazil.
Answer:
Rice and maize

Question 3.
The production of this cereal crop is largely concentrated in the central part of Brazil.
Answer:
Maize.

Question 4.
The major commercial crops of Brazil.
Answer:
Coffee, cocoa, rubber, soyabean and sugarcane.

Question 5.
The largest exporter of coffee and soyabean in the world.
Answer:
Brazil.

Question 6.
The major coffee-growing states of Brazil.
Answer:
Minas Gerais and Sao Paulo.

Question 7.
Fruits are grown in Brazil.
Answer:
Bananas, pineapples, oranges and other citrus fruits.

Question 8.
The region in Brazil where cattle, sheep and goats are reared.
Answer:
Savannah grasslands in the south.

Question 9.
Two factors that have led to limitations in mining in the interior parts of Brazil.
Answer:

Inaccessibility due to dense forests
Lack of knowledge of potential reserves of resources.

Question 10.
The warm current in the eastern coast of Brazil.
Answer:
Brazil current.

Question 11.
The cold current off the south-eastern coast of Brazil.
Answer:
Falkland current.

Question 12.
The main catches of the fishermen in Brazil.
Answer:
Swordfish, shrimp, lobsters, sardines, etc.

Question 13.
Major food crops produced in India.
Answer:
Rice, wheat, maize, sorghum and millets.

Question 14.
Crops grown in plantation in India.
Answer:
Tea, coffee and rubber.

Question 15.
Major cash crops grown in India.
Answer:
Sugarcane, cotton and jute.

Question 16.
Main type of Indian agriculture.
Answer:
Subsistence.

Question 17.
Maj or fish varieties found in the western coastal region of India.
Answer:
Sardines, mackerel, bombay duck and prawns.

Question 18.
The important varieties of fish on the eastern coast of India.
Answer:
Horse mackerels, clupeids and silver bellied carp.

Question 19.
The major freshwater fish variety in India.
Answer:
Silver bellied carp (chopda).

Question 20.
Places where coal is mined in India.
Answer:
Korba in Chhattisgarh and in Eastern Maharashtra

Question 21.
Places where mineral oil wells are found in India.
Answer:
(i) Digboi in Assam
(ii) Mumbai High in the Arabian Sea near Maharashtra
(iii) Kalol and Koyali in Gujarat.

Question 22.
The name of the river mouth, where reserves of mineral oil and natural gas have been discovered.
Answer:
River Godavari.

Question 23.
The state where stones like marble are found.
Answer:
Rajasthan.

Question 24.
The place/state where stones like Cuddapah are found.
Answer:
Cuddappah in Andhra Pradesh.

Question 25.
The states in which fish forms an important part of the diet of many people living in the coastal areas in India.
Answer:
Kerala, West Bengal, Odisha, Andhra Pradesh, Tamil Nadu, Goa and Maharashtra.

Question 26.
States of India where metallic minerals are found.
Answer: Jharkhand, Odisha, adjoining Chhattisgarh and Madhya Pradesh, parts of Rajasthan, Karnataka and Tamil Nadu.

Question 27.
The agro-based industries in India which are heavily concentrated in the raw material- producing areas.
Answer:
Cotton, jute and sugar.

Question 28.
The forest-based industries in India.
Answer:
Paper, plywood, matches, resins and lac.

Question 29.
Industries found in the coastal belt of Kerala in India.
Answer:
Coir, copra and fish canning.

Question 30.
Refineries in India situated close to the petroleum-producing areas.
Answer:
Koyali, Digboi, Noonmati and Bongaigaon.

Question 31.
Refineries in India located away from the coast and oil-producing areas.
Answer:
Mathura and Barauni.

Question 32.
Major salt-producing states in India.
Answer:
Gujarat, Rajasthan and Tamil Nadu.

Question 33.
Brazil’s export items.
Answer:
Iron ore, coffee, cocoa, cotton, sugar, tobacco, oranges and bananas.

Question 34.
Brazil’s import items.
Answer:
Machinery, chemical products, fertilizers, wheat, heavy vehicles, mineral oil and lubricants.

Question 35.
Major trading partners of Brazil.
Answer:
Germany, the USA, Canada, Italy and Argentina, Saudi Arabia.

Question 36.
India’s export items.
Answer:
Tea, coffee, mangoes, spices, leather & leather goods, iron ore, cotton and silk textiles etc.

Question 37.
India’s import items.
Answer:
Petroleum, machines, pearls and precious stones, gold and silver, paper, medicines, etc.

Question 38.
India’s major trading partners.
Answer:
The USA, The UK, Germany, Japan, China, Russia, etc.

Distinguish between:

Question 1.
The Indian companies’ investment in Brazil and Brazil’s investment in India.
Answer:

Indian investment in Brazil	Brazilian investment in India
(i) Indian companies have invested a lot of capital in Brazil. (ii) e.g. IT, pharmaceuticals, energy, agri-business, mining, engineering and auto sectors.	(i) Brazilian companies investment in India is smaller.(ii) e.g. automobiles, IT, mining, energy, biofuels, footwear sectors in India.

Question 2.
Brazil-International Trade and India-International Trade
Answer:

Brazil-International Trade	India-International Trade
(i) Major exports of Brazil are iron-ore, coffee, cocoa, cotton, sugar, tobacco, oranges and bananas. (ii) Major imports of Brazil are machinery, chemical products, fertilizers, wheat, heavy vehicles, mineral oil and lubricants. (iii) Major trading partners of Brazil are Germany, the USA, Canada, Italy, Argentina, India and Saudi Arabia.	(i) Major exports of India are tea, coffee, mangoes, spices, leather and leather goods, iron ore, cotton and silk textiles. (ii) Major imports of India are petroleum, machines, pearls, precious stones, gold and silver, paper, medicines, etc. (iii) Major trading partners of India are the USA, the UK, Germany, Japan, China, Russia, etc.

Question 3.
US Economy and India-Brazil Economies.
Answer:

US Economy	India-Brazil Economy
(i) The US economy is a developed economy. (ii) National income and per capita income of US is far ahead of Brazil and India. (iii) The US has the strength of many patents, modern technology and mechanical strength.	(i) India and Brazil are developing economies. (ii) National income and per capita income of India and Brazil is low. (iii)India and Brazil have just about started progressing in the fields of technology, education and industry.

Mark the following on the outline map:

Question 1.
On the given Political map of Brazil, show the following details (Draw index).

Major coffee producing areas of Brazil.
The cold and warm ocean current near the Brazilian coast.
Important fishing areas in the Northern coast.
Important fishing areas in the Eastern coast.

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 23

Question 2.
Indicate the following on a map of India.

The plateau region rich in minerals.
Region where coal is mined.
State where marble is found.
Cudappah stones are found in this state.
The state whose coastal belt has a concentration of coir, copra and fish canning industries.
Major salt producing state.

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 25

Question 3.
Locate the following regions on the map of India.

Mineral oil wells.
Oil refineries close to petroleum producing areas.
Oil refineries in the interiors.
The mouth of the river where reserves of mineral oil and natural gas have been discovered.

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 8 Economy and Occupations 27

Give Geographical Reasons:

Question 1.
Unlike Brazil, India’s agriculture contributes more towards the GDP.
Answer:

Around 60% of land in India is under cultivation.
Agriculture has been a long standing activity here with a large chunk of population engaged in it.
The enormous expanse of level plains, rich soils, high percentage of cultivable land, wide climatic variety, long growing season, etc. provide a strong base for agriculture in India.
So, unlike Brazil, India’s agriculture contributes more towards the GDP.

Question 2.
Fishing plays an important role in the economy of India.
Answer:

India has a coastline of about 7500 km.
India is one of the largest producer of fish, both marine and inland.
Marine fishing accounts for about 40% of the total annual fish production and the remaining 60% is by freshwater fishing.
Fisheries help in augmenting food supply, generating employment, raising nutritional level and earning foreign exchange.
Fish forms an important part of the diet of many people living in all the coastal states.
Thus, fishing plays a significant role in the economy of the country.

Question 3.
The distribution of industries in India is highly uneven.
Answer:
The distribution of industries is India in highly uneven due to the following reasons:

Uneven distribution of the necessary raw materials and power resources.
There is concentration of enterprises, financial resources and other necessary conditions in large towns.

Question 4.
The North Eastern part of the Indian Peninsula has a high concentration of heavy metallurgical industries.
Answer:
The north eastern part of the Indian Peninsula has a high concentration of heavy metallurgical industries because:

Chattisgarh, Odisha, Jharkhand, West Bengal are rich in minerals.
Large quantities of coal deposits, an important raw material in metallurgical industries is available.
There are availability of refractory materials, cheap power from the Damodar Valley Corporation and a number of thermal power projects.
There is availability of cheap labour in and around this region.

Question 5.
USA is a developed country.
Answer:
The United States is a developed country because:

This country has less but a well-educated population.
It has the strength of many patents, modern technology and mechanical strength.
USA has a very high national income and per capita income.

Question 6.
Brazil is a good fishing ground.
Answer:
Brazil is a good fishing ground because :

Brazil has a sea coast of around 7400 km and excellent fishing grounds off the South Atlantic coast.
The meeting of the warm Brazil current and the cold Falkland current off the coast of South-East Brazil makes it a good fishing ground.

Write short notes on:

Question 1.
Mining in India:
Answer:
(i) The Chhota Nagpur plateau in India is a big storehouse of different minerals. Mining is the main occupation of the people.
(ii) Coal is mined in Korba in Chattisgarh and in Eastern Maharashtra.
(iii) Mineral oil wells are found in Digboi in
Assam, Mumbai High in the Arabian Sea near Maharashtra, Kalol, Koyali in Gujarat.
(iv) Stones like marble are found in Rajasthan and Cuddapah in Andhra Pradesh.

Question 2.
Industries in Brazil:
Answer:
(i) Major industries of Brazil are iron and steel, automobile assembling, petroleum processing, chemical production and cement making.
(ii) Technologically based industries have been the most dynamic in recent years.
(iii) Food-processing industries, cotton textiles, silk and woollen industries have developed well.
(iv) Most large industries are concentrated in the south and south-east of Brazil.

Question 3.
Agro-based and forest-based industries in India.
Answer:
(i) Agro-based industries: The agro-based industries including cotton, jute and sugar are heavily concentrated in the raw material producing areas.
(ii) Forest-based industries: The forest based industries including paper, plywood, matches, resins and lac are increasingly finding mostly found in the forest areas of various states.

10th Std Geography Questions And Answers:

Population Question Answer Class 10 Geography Chapter 6 Maharashtra Board

February 7, 2025February 6, 2025 by Bhagya

Balbharti Maharashtra State Board Class 10 Geography Solutions Chapter 6 Population Notes, Textbook Exercise Important Questions and Answers.

Std 10 Geography Chapter 6 Question Answer Population Maharashtra Board

Class 10 Geography Chapter 6 Population Question Answer Maharashtra Board

Geography Class 10 Chapter 6 Question Answer Maharashtra Board

1. Are the following sentences right or wrong? Correct the wrong ones.

Question a.
Literacy rate is higher in Brazil than India.
Answer:
Right.

Question b.
In Brazil, people prefer living in the south east as compared to the north east.
Answer:
Right.

Question c.
The life expectancy of Indians is decreasing.
Answer:
Wrong.

Question d.
The north-western part of India is densely populated.
Answer:
Wrong.

Question e.
The western part of Brazil is densely populated.
Answer:
Wrong

2. Answer the following questions as per the instructions:

Question a.
Arrange the following states of India in descending order of their population. Himachal Pradesh, Uttar Pradesh, Arunachal Pradesh, Madhya Pradesh, Andhra Pradesh.
Answer:
Descending order: Uttar Pradesh, Madhya Pradesh, Andhra Pradesh, Himachal Pradesh, Arunachal Pradesh.

Question b.
Arrange the states of Brazil in ascending order of their population: Amazonas, Rio de Janeiro,
Alagoas, Sao Paulo, Parana.
Answer:
States of Brazil: Alagoas, Amazonas, Parana, Rio de Janeiro, Sao Paulo.

Question c.
Classify the factors affecting the distribution of population into favourable and unfavourable.
Answer:

Favourable Factors	Unfavourable Factors
(1) Nearness to Sea	Lack of roads
(2) Temperate Climate	Lack of Industries
(3) New cities and towns	Tropical moist forests
(4) Minerals	Semi arid climate
(5) Cultivable land

3. Answer the following questions:

Question a.
Explain the similarities and differences between the population distribution in Brazil and India.
Answer:
(a) Similarities in population distribution in Brazil and India:

In Brazil as well as in India, population is very unevenly distributed.
Inaccessible dense forests and absence of facilities are the barriers to human settlements.
North, north west and north east of both the countries are the regions of low population.
Population is concentrated in flat fertile regions which have abundant water resources, transport facilities, mild climate and development of agriculture industries and trade in the plain region.
Coastal regions are densely populated in Brazil and in India.

(b) Differences between population distribution in Brazil and India.

The average density of population in India is 382 persons per sq.km, and that of Brazil is about 23 persons per sq.km.
Though the area of both the countries is occupied by vast river basins, the distribution of population is extremely opposite in both the river basins.
The Amazon River Basin is sparsely populated while the Ganga River Basin is densely populated.

Question b.
Giving examples, correlated to, climate and population distribution
Answer:
Climate and population distribution are closely interreleted. Temperature and rainfall, the two elements of climate greatly influence the population concentration.

(i) Dense population is found in regions with mild climate and moderate rainfall.
E.g. the coastal plains of Brazil, the northern plain as well as the coastal plains of India

(ii) Places with heavy rainfall, inaccessibility and dense forests have low population.
E.g. the interiors of the Amazon Basin in Brazil, north eastern states in India.

(iii) The snow covered regions due to extremely cold climatic conditions have less population.
E.g. the northernmost part of Jammu & Kashmir.

(iv) In certain regions, due to less rainfall and extreme climatic conditions population is sparse.
E.g. Thar desert of Rajasthan and the Drought Quadrilateral region of Brazil.

4. Give geographical reasons:

Question a.
Population is an important resource.
Answer:

The qualitative aspects of a population are important for a nation’s economic and social progress.
Natural resources of any country gets utilised properly because of the population.
Economic growth and development will be slow if population resource is not utilised properly.
Thus an optimum and quality population can bring about a country’s development.

Question b.
Brazil’s population density is very less.
Answer:

Brazil is the fifth largest country in the world with respect to area and has a population of about 19 crores (Census 2010).
It occupies 5.6% of world’s total land area and accounts for only 2.78% of the world’s total population.
Thus Brazil occupies more percent of world’s land and less percent of world’s total population. Therefore,
the density of population is very less in Brazil, i.e. around 23 persons per sq.km.

Question c.
India’s population density is high.
Answer:

India is the second most populous country in the world, with a population of about 121 crores (Census 2011).
India occupies only 2.41% of the land area of the world, but supports 17.5% of the world’s population.
Thus India has less percent of world’s land and supports high percent of world’s population.
Hence, India’s average population density is high i.e. 382 persons per sq. km.

Question d.
The density of population is sparse in the Amazon Basin.
Answer:

The interior part of the Amazon Basin has a very unfavourable hot and humid climate.
It receives heavy rainfall of nearly 2000 mm and has dense inaccessible forests.
Transportation, agricultute and industries are not well developed here.
All these factors are barriers to the development of human settlements.
So, the density of population is sparse in the Amazon Basin.

Question e.
Population density is high in the Ganga plains.
Answer:

Ganga plains are fertile low lying plains formed due to the deposition work of River Ganga and its tributaries.
Mild climate, moderate rainfall and fertile soil have led to the development of agriculture and industries.
This region also has a dense network of roadways and railways.
So, the population density is high in the Ganga Plains.

5. Observe the following diagram and answer the following questions:

Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 1
Question 5A.
Compare and classify the population densities shown in the figure ‘a’ and ‘b’ representing 1 sq. km. of area.
Answer:
In the fig. (a) density of population is 7 persons per sq. km. The region is sparsely populated.
In the fig. (b), the density of population is 18 persons per sq. km. The region is densely populated.

Question 5B.
If in figure B one sign = 100, then what will be the sex ratio?
Answer:
One symbol = 100 persons
There are 10 female symbols.
Number of females = 100 x 10
= 1000
There are 8 male symbols
Number of males = 100 x 8
= 800

Males	800	1000
Females	1000	?

Number of females = $\frac { 1000 X 1000 }{ 800 }$
= 1250
Sex Ratio is 1250 females per 1000 males.

Question 6.
Comment upon the population density of fig (b).
(i) fig (b) shows the population density of India as per 2011.
(ii) The density of population is divided into four categories. They are:
(a) Less than 100 persons per sq.km. .
(b) 101-250 persons per sq.km.
(c) 251-500 persons per sq.km.
(d) more than 500 persons per sq.km.
Answer:

S.No.	Population Density (per sq.km.)	Name of the States / Union Territories
(1)	less than 100	Arunachal Pradesh, Mizoram, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim.
(2)	101 to 250	Meghalaya, Manipur, Nagaland, Rajasthan, Madhya Pradesh, Chattisgarh.
(3)	251 to 500	Gujarat, Maharashtra, Goa, Karnataka, Andhra Pradesh, Telangana, Odisha, Jharkhand, Assam, Tripura.
(4)	more than 501	West Bengal, Bihar, Punjab, Haryana, Uttar Pradesh,Kerala and Tamil Nadu, Delhi, Chandigarh, Puducherry, Diu, Daman, Dadra Nagar, Haveli, Andaman and Nicobar Islands.

Class 10 Geography Chapter 6 Population Intext Questions and Answers

Study the maps and answer the following questions

Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 9
Question 1.
States with the highest population density.
Answer:
West Bengal, Bihar, Punjab, Haryana, Uttar Pradesh, Kerala and Tamil Nadu.

Question 2.
On the basis of maps given above, classify the distribution population in India in the following table.
Answer:

S.No.	Population Density (per sq.km.)	Name of the States / Union Territories
(1)	less than 100	Arunachal Pradesh, Mizoram, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim.
(2)	101 to 250	Meghalaya, Manipur, Nagaland, Rajasthan, Madhya Pradesh, Chattisgarh.
(3)	251 to 500	Gujarat, Maharashtra, Goa, Karnataka, Andhra Pradesh, Telangana, Odisha, Jharkhand, Assam, Tripura.
(4)	more than 501	West Bengal, Bihar, Punjab, Haryana, Uttar Pradesh, Kerala and Tamil Nadu, Delhi, Chandigarh, Puducherry, Diu, Daman, Dadra Nagar, Haveli, Andaman and Nicobar Islands.

Question 3.
States with lowest population density.
Answer:
Arunachal Pradesh, Sikkim, Jammu and Kashmir, Himachal Pradesh, Uttarakhand and Mizoram.

Question 4.
Correlate the climate and physiography of India with its population distribution and write a note on it.
Answer:
(i) Climate and population distribution are closely inter-related.

(ii) Temperature and rainfall are the two elements of climate which greatly influence the population distribution.

(iii) Dense population is found in regions with mild climate and moderate rainfall.
E.g. the northern plain as well as the coastal plains of India

(iv) Places with heavy rainfall, inaccessibility and dense forests have low population.
E.g. northeastern states in India.

(v) The snow-covered regions due to extremely cold climatic conditions have less population.
E.g. the northernmost part of Jammu and Kashmir.

(vi) In certain regions, due to less rainfall and extreme climatic conditions population is sparse.
E.g. Westernmost part of India in the Thar desert, Rajasthan.

Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 8

Question 1.
In which area is population greatly concentrated?
Answer:
Population is greatly concentrated in the south eastern part of Brazil.

Question 2.
In which area is the distribution of population sparse?
Answer:
The Amazon Basin in the nothern part and the central and western parts of Brazil have sparse distribution of population.

Question 3.
Prepare a note on factors responsible for the uneven distribution of population based on the study of Brazil you have made so far.
Answer:
The distribution of population in Brazil is uneven:

There is sparse population in the Amazon Basin due to hot and humid climate, heavy rainfall, dense forests, inaccessibility.
The population is low in the swampy areas of Pantanal.
Low population is found in the central and western part of Brazil due to lack of minerals, low rainfall, hot and dry climatic conditions.
The distribution of population is moderate in Brazilian Highlands.
High population is found in the coastal regions and the southern part of Brazil. This is due to flat fertile land and abundant availability of minerals due to which agriculture, industries and trade have developed.

Question 4.
Identify the type of map showing distribution fig. (a) of textbook.
Answer:
The type of map showing distribution of population is a dot map.

Question 5.
On the basis of the map (b), classify the distribution of population in Brazil in the following table.:

S. No.	Population Density	Names of the places
(1)	Less than 50	Acre, Amazonas, Roraima, Rondonia, Para, Amapa, Mata Grasso, Mato Grasso Do Sul, Goias, Tocantins, Maranhao, Piaui, Bahia, Minas Gerais, Rio Gande Do Sul
(2)	51 -100	Paraiba, Pamambuco, Parana, Santa Catarina, Sergipe, Rio Grande Do Norte, Ceara
(3)	101 -150	Alagoas
(4)	151 – 300	Sao Paulo
(5)	More than 300	Rio de Janerio, Brasilia

USE YOUR BRAIN POWER

Question 1.
Calculate the population density of the area shown in 1 sq.km, of square in ‘a’ and ‘b’ each
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 4
Answer:
(a) In fig. (a) there are 16
Each = 80 people
Total number of people = 16 x 80 = 1280
Fig. (a) has a population density of 1280 people per sq. km.

(b) In fig. (b) there are 23
Each = 80 people
Total number of people = 23 x 80 = 1840
Fig. (b) has a population density of 1840 people per sq. km.

GIVE IT A TRY

Question 1.
What could be the reasons of lower sex ratio in any region?
Answer:
With reference to both the countries, the characteristics of population are prominently notable.

The sex ratio of Brazil has been more than 1000 since decades.
Considering the sex ratio of Brazil, the number of women have considerably increaesed than men since 2001.
In India men outnumber women.
In India we see fluctuations in the sex ratio since few decades. There has been a slight increase in the sex ratio after 1991.

Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 5

Question 2.
Write a similar conversation using the graph
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 10
Answer:
A: What do these graphs show?

B: These graphs show the literacy rate of India and Brazil.

A: What do you mean by literacy rate?

B: It means the total percentage of the population of an area at a particular time aged seven years or above ‘ who can read and write with understanding.

A: It means that, as on today’s date, the literacy rate of our country is 72.2%.

B: But, Brazil had an even higher literacy rate decades back in 1981, i.e. 74.6% and it has touched 92.6 as of today (2018), which is quite commendable.

A: Yes, definitely But, we have also seen a steady growth in the literacy rate of the country, especially, during the period between 1991 and 2011.

B: Still, though we are growing, we are way behind Brazil today with 72.2% because they have a much higher literacy percentage of 92.6.

A: What measures can be adopted to increase the literacy rate of our country?

B: We can make people aware of the need and importance of education, help in teaching them, introducing various literacy campaigns by making use of free calls, free sms services, etc.

Question 3.
Study the indices of density maps of both the countries. What difference do you find? What conclusions can you draw?
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 4
Answer:
(i) India’s density of population is proportionately catered while Brazil’s density of population is concentrated only on the eastern coast.
(ii) After studying the indices of the density maps of both the countries, we can conclude that India’s population density is much higher than that of Brazil.
(iii) The lowest value on the map of India indicates less than 100 whereas on the Brazil map it is less than 50.
(iv) Places in Brazil which are highest in density is grouped in the category of more than 300 people’ per sq. km. whereas in India it is more than 500 persons per sq. km.

Question 4.
Considering the above discussion, what should be done so that our manpower is utilized properly, sex ratio improves and population growth is controlled? Write two to three sentences on each.
Answer:
(i) Measures to utilise man power properly:

Good education, health and training facilities are the basic requirements to improve human resources.
The focus of education should not just be to chum out jobseekers but also to chum out job creators.
The young population should be encouraged to be entrepreneurs.

(ii) Measures to improve sex ratio:

Build an environment to save and protect the girl child.
Ban sex determination test.

(iii) Measures to control population growth:

Family planning measures to be encouraged through media.
Spread of education among illiterate masses, especially about the benefits of having a small family.
Child marriage should be strictly prohibited.

TRY THIS

Age and Sex Pyramid:
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 6

Question 1.
What is this figure called? What is it always known as?
Answer:
The figure is called the Age-Sex Pyramid. It is also known as Population Pyramid.

Question 2.
What does the graph depict?
Answer:
The graph depicts the percentage of male and female population of various age groups in Brazil & India for the year 2016.

Question 3.
In which country is the proportion of adults more?
Answer:
The proportion of adults is comparatively more in India.

Question 4.
‘This country’s population is getting slowly older’. Which country is being referred to? Why?
Answer:
‘This country’s population is getting slowly older – The country being referred to is Brazil. As compared to India, a larger percentage of Brazil’s population falls in the above 60 years age group. So it is said that Brazil’s population is getting slowly older.

Question 5.
In which country are the number of children comparatively more?
Answer:
The proportion of children is comparatively more in India.

Question 6.
While comparing the age-sex pyramids, which pyramid has a broader base?
Answer:
While comparing the age-sex pyramids, India’s pyramid has a broader base.

USE YOUR BRAIN POWER

Question 1.
Is there a relationship between increase in life expectancy and growth of population ? How?
Answer:
(i) Yes, there is a relationship between increase in life expectancy and growth of population.
(ii) Increased life expectancy means there are more people who live longer, which means healthier and better quality of life.
(iii) This kind of population generally prefers fewer children which leads to decreased birth rates.

Question 2.
If the proportion of dependent age groups increases in the composition of population, how will it affect the economy of a country?
Ans.
(i) If the proportion of dependent age groups increases in the composition of population, it will have an adverse effect on the economy of a country.
(ii) The reason is if the working population is less, the economic activities will reduce and will have a direct impact on the economic growth and development of that nation.
(iii) The production will decrease in comparison to consumption leading to inflation also the per capita income and GDP will decrease.
(iv) Export will reduce and imports will increase.
(v) The proportion of the working population will increase, slowing down the pace of development.

Class 10 Geography Chapter 6 Population Additional Important Questions and Answers

Choose the correct option and rewrite the statements:

Question 1.
The ______ aspects of a population are important for a nation’s economic and social progress.
(a) quantitative
(b) qualitative
(c) measurable
(d) calculable
Answer:
(b) qualitative

Question 2.
India is the ________ most populous country in the world.
(a) second
(b) fifth
(c) seventh
(d) sixth
Answer:
(a) second

Question 3.
Due to farming, industries and trade, the proportion of the population got in _____ a few places.
(a) distributed
(b) sparse
(c) concentrated
(d) equal
Answer:
(c) concentrated

Question 4.
In mountainous / hilly regions, dry desert areas and densely forested areas, population density is __________ because of inaccessibility, absence of facilities and tough life.
(a) high
(b) very high
(c) sparse
(d) moderate
Answer:
(c) sparse

Question 5.
Brazil is the _______ populated country in the continent of South America.
(a) second most
(b) third most
(c) fifth most
(d) most
Answer:
(d) most

Question 6.
With a population of around 19 crores, according to Census 2010, Brazil ranks _______ in the world.
(a) 3rd
(b) 5th
(c) 7th
(d) 9th
Answer:
(b) 5th

Question 7.
With respect to area, Brazil stands _______ in the world.
(a) 3rd
(b) 5th
(c) 7th
(d) 9th
Answer:
(b) 5th

Question 8.
A majority of Brazilians have concentrated within 300 kilometers of the ________.
(a) Guyana highlands
(b) Amazon river,
(c) Eastern coastal areas
(d) Pantanal wetlands
Answer:
(c) Eastern coastal areas

Question 9.
The interior of the Amazon basin is ____ populated.
(a) densely
(b) moderately
(c) highly
(d) very sparsely
Answer:
(d) very sparsely

Question 10.
The central and western parts of Brazil is ______ populated.
(a) densely
(b) sparsely
(c) moderately
(d) less
Answer:
(d) less

Question 11.
The density of population in the _______ of Brazil is moderate.
(a) Amazon Basin
(b) coastal lowlands
(c) highlands
(d) forested areas
Answer:
(c) highlands

Question 12.
In India, there has been a _______ in the sex ratio, after 1991.
(a) decrease
(b) slight increase
(c) consistency
(d) steep increase
Answer:
(b) slight increase

Question 13.
The proportion of _______ in India is more.
(a) middle-aged people
(b) old people
(c) children
(d) youth
Answer:
(d) youth

Question 14.
The rate of population growth is now ______ in India.
(a) increasing
(b) declining
(c) stable
(d) stagnant
Answer:
(b) declining

Question 15.
It is observed that Brazil’s population may not increase in the next ______ decades.
(a) two
(b) three
(c) four
(d) five
Answer:
(a) two

Question 16.
The eastern coastal areas of Brazil are also called the coastal ________.
(a) lowlands
(b) highlands
(c) ravines
(d) badlands
Answer:
(a) lowlands

Question 17.
In most of the developing countries life expectancy is still less, but with socio economic development it is ________.
(a) decreasing
(b) increasing
(c) gradually declining
(d) steeply increasing
Answer:
(b) increasing

Match the columns:

S.No	Column ‘A’	Column ‘B’
(1)	Coastal lowlands	(a) sparsely populated
(2)	Amazon Basin interior	(b) moderately populated
(3)	Highlands	(c) densely populated (within 300 kms. of the area)

Answer:
1 – c
2 – a
3 – b

Answer the following questions in one or two sentence.

Question 1.
According to Census 2011, what is India’s population and how much is its average population density?
Answer:
According to Census 2011 India’s population is around 121 crores, and its average population density is 382 persons per sq. km.

Question 2.
What percentage of the total land area of the world is occupied by India and Brazil?
Answer:
India occupies only 2.41% of the land area of the world, whereas Brazil occupies 5.6% of the world’s total land area.

Question 3.
What is the difference in the percentage of the world population supported by India and Brazil?
Answer:
India supports 17.5% of the world’s population, whereas Brazil supports 2.78% of the world’s total population. The difference is 14.72% (India has a large population than Brazil)

Question 4.
According to Census 2010, what is the total population of Brazil and what is its average population density?
Answer:
According to Census 2010, Brazil’s total population is around 19 crores and its average population density is 23 persons per sq. km.

Question 5.
What is sex ratio?
Answer:
Sex ratio means, the number of females per 1000 males in a region.

Question 6.
What is a population pyramid?
Answer:
A population pyramid, also called age-sex pyramid, is a graphical illustration that shows the age and sek/gender related aspects of various age groups in a population.

Question 7.
How is the population pyramid useful? OR State the uses of a population pyramid.
Answer:

The population pyramid is used to study the age and sex related aspects of a region’s population
We can know the number/percentage of various age groups of males and females in a country.
It also helps us to know the proportion of children, youth and old people in a country.

Question 8.
What is life expectancy?
Answer:
Life expectancy means the average number of years, a person born in a country is expected to live.

Question 9.
Which factors lead to an increase in average life expectancy?
Answer:
Improvement in medical facilities, progress in the medical field and access to nutritious food lead to an increase in average life expectancy.

Name the following:

Question 1.
Indian cities that are densely populated.
Answer:
Delhi, Kolkata, Mumbai, Pune, Bengaluru, Chennai.

Question 2.
Factors that play an important role in the distribution of population.
Answer:
Physiography and climate.

Question 3.
Factors due to which human settlements have been established for many centuries.
Answer:
Fertile land, plain land and availability of water.

Question 4.
Factors due to which population got concentrated in a few places, in India.
Answer:
Farming, industries and trade.

Question 5.
Areas which have sparse population density in India.
Answer:
Mountainous / hilly regions, dry desert areas, dense forest areas.

Question 6.
Factors due to which population density is sparse in a few areas.
Answer:
Inaccessibility, absence of facilities and tough life.

Question 7.
The most populated country in South American.
Answer:
Brazil.

Question 8.
Brazil’s rank in the world with regard to population as well as land area.
Answer:
Fifth.

Question 9.
The part of Brazil has the maximum concentration of population
Answer:
Eastern coastal areas or coastal lowlands.

Question 10.
The part of Brazil that is sparsely populated.
Answer:
Amazon River Basin.

Question 11.
The region of Brazil that is moderately populated.
Answer:
The Highlands.

Question 12.
The parts of Brazil that are less populated.
Answer:
Central, western and interior of Amazon basin.

Question 13.
Out of Brazil and India, the country where men outnumber women.
Answer:
India.

Question 14.
Increase in this factor is an indicator of development of that society.
Answer:
Life expectancy, Sex Ratio and Literacy Rate.

Question 15.
The development of this aspect of an economy leads to an increase in average life expectancy.
Answer:
Socio-economic development.

Are the following sentences right or wrong?

Question 1.
India is the fifth most populous country in the world.
Answer:
Wrong.

Question 2.
India’s average population density is 832 persons per sq. km. as per the 2011 Census.
Answer:
Wrong.

Question 3.
Brazil is the second-most populous country in the World.
Answer:
Wrong.

Question 4.
Brazil ranks fifth in the world with respect to area.
Answer:
Right.

Question 5.
The total population of Brazil is around 91 crores.
Answer:
Wrong.

Question 6.
In Brazil and India, population is evenly distributed.
Answer:
Wrong.

Question 7.
The central and western part of Brazil are less populated.
Answer:
Right.

Question 8.
The sex ratio of Brazil has been less than 1000 since centuries.
Answer:
Wrong.

Question 9.
It is observed that in Brazil, the rate of population growth is increasing.
Answer:
Wrong.

Fill the map with the given information:

Question 1.
On a map of India, show the following.

Largest state areawise.
Smallest state areawise.
State with highest population.
State with lowest population.
State having highest density of population.
State having lowest density of population.
State having highest sex ratio.
State having lowest sex ratio.
State having highest literacy rate.
State having lowest literacy rate.

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 11

Question 2.
On a map of Brazil, show the following.

Largest state areawise.
Smallest state areawise.
State with highest population.
State with lowest population.
State having highest density of population,
State having lowest density of population.

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 12

Give geographical reasons:

Question 1.
In India, population is very unevenly distributed.
Answer:
(i) In India, population is very unevenly distributed.
(ii) Physiography and climate play an important role in the distribution of population.
(iii) Due to fertile land, plain land and availability of water, human settlements have been established in some parts for many centuries.
(iv) Due to farming, industries and trade, the . proportion of the population has become concentrated in a few places.
(v) For example, the Northern Plains of the country, Delhi, Kolkata, Mumbai, Pune, Bengaluru, Chennai, etc.
(vi) On the contrary, in mountainous / hilly regions, dry desert areas, dense forest areas, density is sparse because of inaccessibility, absence of facilities and tough life.

Question 2.
The distribution of population is very uneven in Brazil.
Answer:
(i) The distribution of population is very uneven in Brazil. .
(ii) A majority of the Brazilians are concentrated within 300 kilometers of the eastern coastal areas also called the coastal lowlands because agriculture and industries are well developed here.
(iii) In the interior of the Amazon Basin population is very sparse due to.
(iv) Unfavourable climate, heavy rainfall,
inaccessibility and dense forests which are the barriers to development of human settlements here.
(v) The central and western part of Brazil is less moderate.

Question 3.
The average life expectancy in India is increasing.
Answer:
(i) Earlier the average life expectancy in India was low due to, lack of medical facilities which lead to high incidence of diseases and epidemics like chicken pox, malaria, cholera, etc.
(ii) Today with improvement in access to medical facilities and improvement in technology, diseases and epidemics are controlled.
(iii) Also today people in India have an improved standard of living, they eat nutritious food and there is awareness of good health.
All this has led to increase in average life expectancy in India.

Question 4.
In north-eastern India, sparse distribution of population is found.
Answer:
(i) North East India comprises of dense forests and uneven topography.
(ii) There exist unfavourable climatic conditions in this part.
(iii) There is less development of transport, communication and industries here.
So, in north-eastern India, sparse distribution of population is found.

Question 5.
In India, number of men outnumber women. Is this condition found in all the states of India?
Answer:
In India, men outnumber women, on an average. But in Kerala women outnumber men. Sex Ratio of Kerala is 1084 females per 1000 males (2011 Census).

Question 6.
Explain the reasons of low sex ratio in India.
Answer:
Some of the reasons for lower sex ratio in any region are:

Illiteracy: Narrow mindedness and lack of education leads to gender bias in the society.
Preference for a male child : There is preference of a boy child over a girl child. Nutrition to girls is ignored.
Poverty: Povertystruck families do not prefer a girl child as they consider female child a burden due to practices like dowry prevalent in the society.
Female foeticide and female infanticide: Female foeticide and female infanticide are on the rise due to the wrong use of modem technology.
Maternity deaths: Higher maternity deaths have lowered the sex ratio.

Question 7.
Explain – The growth rate of population in India is decreasing but population is increasing.
Answer:
(i) Growth rate of population is calculated on the basis of difference between birth rate and death rate.
(ii) Earlier the difference between birth rate and death rate was high, so the growth rate was high.
(iii) Today the growth rate is decreasing because the difference between birth rate and death rate is not as high as it was earlier.
So it is said that in India the growth rate of population is decreasing, but the population is increasing.

Question 8.
Explain the uneven distribution of population in India.
Answer:
(i) Dense population is found in regions with mild climate and moderate rainfall. E.g. the northern plain as well as the coastal plains of India
(ii) Places with heavy rainfall, inaccessibility and dense forests have low population. E.g. north eastern states in India.
(iii) The snow covered regions due to extremely cold climatic conditions have less population. E.g. the northernmost part of Jammu & Kashmir.
(iv) In certain regions, due to less rainfall and extreme climatic conditions population is sparse. E.g. westernmost part of India in the Thar desert, Rajasthan.
(v) Moderate population is found in the plateau regions of Narmada valley.

Try this

Population growth rate graphs :
Look at the graphs in Fig. indicating the population growth rate of Brazil and India and answer the following questions.
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 14
Question 1.
What is the common feature in both the graphs?
Answer:
Both the graphs are indicating a downward trend in population growth rate of Brazil and India.

Question 2.
What is India’s growth rate of population in 2011?
Answer:
India’s population growth rate in 2011 is 1.5%.

Question 3.
In which two decades has the population growth rate of India remained almost stable?
Answer:
The population growth rate of India has remained almost stable during the two decades 1971 to 1981 and 1981 to 1991.

Question 4.
From which time period has Brazil seen a sharp decline in the population growth rate?
Answer:
From 1980-1990, Brazil has seen a sharp decline in the population growth rate.

Question 5.
What is the main point of difference between the two graphs?
Answer:
(i) In the first decade between 1961-1971 the growth rate in India showed an upward trend whereas Brazil has a downward trend throughout.
(ii) Also the decline in Brazil is more sharp but India’s decline in the growth rate is marginal.

Question 6.
What is the interesting feature of Brazil’s growth rate of population?
Answer:
The interesting feature of Brazil’s population growth rate is that it is about to touch 0.0 and then will begin its negative growth rate i.e. the population will start decreasing.

Observe the figure carefully and answer the following questions given below.
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 15
Question 1.
What is the class interval of the data?
Answer:
The class interval of the data is 10 years.

Question 2.
In which decade was India’s life expectancy the highest?
Answer:
Highest life expectancy in India was in the decade of 1960-1970.

Question 3.
In which year has the difference in the life expectancy between Brazil and India been the maximum? By how much?
Answer:
In the year I960, the difference between the life expectancy of Brazil and India has been the maximum by 13 years. (54 – 51)

Question 4.
Has the difference in life expectancy been increasing or decreasing?
Answer:
During the past 36 years, i.e. from 1980 onwards, the difference between the life expectancy of Brazil and India has remained constant. It has been 7 to 8 years.

Question 5.
What is the similarity between both the graphs?
Answer:
Both India and Brazil have experienced an increase in the life expectancy. Both the graphs indicate an upward trend continuously.

Question 6.
Is the increase in life expectancy a positive or a negative indicator of an economy? Why?
Answer:
The increase in life expectancy is a positive indicator for any economy because longer the people’s average age, longer is their contribution towards the growth of an economy.

Based on the figure, observe carefully and answer the questions given below.
Maharashtra Board Class 10 Geography Solutions Chapter 6 Population 16
Question 1.
What do the graphs indicate?
Answer:
The graphs indicate the literacy rate of India and Brazil (in percentage).

Question 2.
What is this general conclusion that you can come to, after observing both the graphs?
Answer:
On observing both the graphs, we can conclude that Brazil is and has always been way ahead of India with regard to literacy rate.

Question 3.
Which country has higher literacy rate?
Answer:
Brazil has a higher literacy rate.

Question 4.
What was the literacy rate of Brazil in 2011?
Answer:
Brazil had a literacy rate of 91.4% in 2011.

Question 5.
What is the difference in the literacy rate of Brazil and India in 2016?
Answer:
Literacy rate of Brazil and India had a difference of 20.4% (92.6 – 72.2) in 2016.

Question 6.
What is the difference in the literacy rate of India between the years 2001 and 2011?
Answer:
The difference in the literacy rate of India is 8.3% (69.3 – 61) between the years 2001 and 2011.

10th Std Geography Questions And Answers:

Climate Question Answer Class 10 Geography Chapter 4 Maharashtra Board

February 7, 2025February 6, 2025 by Bhagya

Balbharti Maharashtra State Board Class 10 Geography Solutions Chapter 4 Climate Notes, Textbook Exercise Important Questions and Answers.

Std 10 Geography Chapter 4 Question Answer Climate Maharashtra Board

Class 10 Geography Chapter 4 Climate Question Answer Maharashtra Board

Geography Class 10 Chapter 4 Question Answer Maharashtra Board

Question 1.
Write names of the States/Regions in appropriate columns.
Bihar, Tocantins, Pernambuco, Alagoas, Eastern Maharashtra, Western part of Rajasthan, Gujarat, Rio Grande Do Norte, Paraiba, Western Ghats, Eastern Himalayas, Western Andhra Pradesh, Roroima, Amazonas, West Bengal, Rio Grande Do Sul, Santa Catarina, Goa
Answer:

States/Regions	India	Brazil
High rainfall	Western Ghats, Eastern Himalayas, Goa	Tocantins, Rio Grande Do Sul, Roraima
Moderate rainfall	Bihar, Eastern Maharashtra West Bengal	Santa Catarina, Amazonas, Alagoas
Low rainfall	Western part of Rajasthan, Gujarat, Western Andhra Pradesh	Pernambuco, Paraiba, Rio Grande Do Norte, Alagoas

2. State whether right or wrong. Rewrite the wrong sentences

Question a.
The fact that Brazil lies on the equator affects its climate in a big way.
Answer:
Right.

Question b.
India and Brazil have the same seasons at the same time.
Answer:
Wrong – India and Brazil have different seasons at the same time.

Question c.
India faces tropical cyclones frequently.
Answer:
Right.

Question d.
Brazil gets a lot of rainfall because of the southwest monsoon winds.
Answer:
Wrong – Brazil gets rainfall from South-East Trade Winds and North-East Trade Winds.

3. Give geographical reasons:

Question a.
The north-eastern part of Brazilian Highlands receives very less rainfall.
Answer:
(i) Brazil gets rainfall from the South-East Trade Winds and the North-East Trade Winds.
(ii) Parts of the Brazilian Highlands extend upto the northern coast.
(iii) The Escarpments act as an obstruction to the winds blowing from the sea and cause orographic type of rainfall in the coastal region.
(iv) Beyond the Highlands, the effect of these winds gets reduced. As a result, the rainfall is minimal.
(v) Thus the North Eastern part of Brazilian highlands receives less rainfall. This rain shadow region is also called the ‘Drought Quadrilateral’.

Question b.
Snowfall doesn’t always occur in Brazil.
Answer:
(i) Because of the vast latitudinal extent of Brazil, it experiences a wide range of climatic variations. Near the Equator it is hot, while tropical type of climate is found near the Tropic of Capricorn.

(ii) Considering the temperatures in Brazil, the northern part of Brazil is hot while the temperatures in the southern part are comparatively lower.

(iii) It generally snows in those areas lying in the temperate or polar regions or in the mountainous regions of very high altitude.

(iv) Snowfall does occur but is only confined to higher elevations in the southern states of Rio Grande Do Sul, Parana and Santa Catarina.

(v) Most part of the country lies in the tropical zone which experiences a hot and humid climate.

So snowfall doesn’t always occur in Brazil and is considered a rare phenomenon.

Question c.
Convectional type of rainfall is not prominent in India.
Answer:
(i) Convectional rains are a feature of the equatorial regions and the equator passes through the northern part of Brazil.
(ii) Due to the intense heat here the air expands and rises upwards. As the air goes upwards it cools down, condensation occurs and clouds are formed. This leads to convectional rains every day.
(iii) As such conditions do not exist in India, convection rainfall is not prominent here.

Question d.
Tropical cyclones occur rarely in Brazil.
Answer:
(i) In the coastal regions of Brazil near the Equator, differences in temperatures are negligible.
(ii) The winds move in the vertical direction in this equatorial region.
(iii) Similarly, the convergence zone of the trade winds is weak here. As a result, cyclones are not formed.
(iv) As a result tropical cyclones occur rarely in Brazil.

Question e.
There is not much difference in the range of temperature in Manaus.
Answer:
(i) Manaus is located to the north of Brazil and close to the Equator.
(ii) This region receives perpendicular rays of the sun throughout the year.
(iii) It also receives convectional type of rainfall every day.
(iv) So the climate is hot and humid throughout the year.
(v) As, there is not much difference in the maximum and minimum temperatures there is not much difference in the range of temperature in Manaus.

Question f.
India receives precipitation from the North East Monsoon Winds too.
Answer:
(i) In the winter season, India is influenced by the North East Monsoon Winds.
(ii) These winds bring cool breeze to the country.
(iii) While blowing over Bay of Bengal the North East Monsoon Winds pick up moisture and give rain to the eastern coast of Andhra Pradesh and Tamil Nadu in India.
So, it is said that India receives precipitation from the North East Monsoon Winds too.

4. Answer the following questions:

Question a.
Describe in brief the changes occurring in the climatic conditions of India while going from south to north.
Answer:
(i) India’s Climate is of monsoon type. But there is diversity in climatic conditions of India due to the latitudinal location and altitude of the place.

(ii) As the Tropic of Cancer passes through middle of India, it divides the country into tropical region and sub tropical region.

(iii) The tropical region receives nearly vertical rays of the Sun and the temperature increases as we move towards the south.

(iv) In the sub tropical region of the north, summers are very hot and winters are very cool and dry.

(v) The Himalayas lie in the northern part of India. They protects us from the cold winds that blow from the north, obstructs the South West Monsoon Winds which results in orographic rainfall in its southern slopes.

(vi) In major parts of India precipitation is in the form of rainfall, but in the Himalayas it is in the form of snowfall.

Question b.
Explain the importance of the Himalayas and the Indian Ocean with respect to the climate of India.
Answer:
(i) The Indian Ocean and the Himalayan ranges exert a great influence on the climate of India and the origin of monsoons.

(ii) Because of high temperatures in summers, a low pressure area develops in the Punjab Plains and the Thar Desert of Rajasthan.

(iii) At the same time a high pressure region develops over the Indian Ocean.

(iv) This attracts winds and they start blowing from the Indian Ocean towards the mainland India.

(v) These are moisture-laden winds which bring rainfall to India.

(vi) These winds move towards the Himalayas and due to the natural obstruction of the Himalayas, orographic rain occurs.

(vii) Later these winds retreat from the Himalayas and move from the north-east towards the Indian Ocean and brings rain to some parts of the Peninsula.

(viii) Also the severe cold winds blowing from the north are obstructed by the Himalayas and it saves India from severe winters.

Question c.
Discuss the factors affecting the climate of Brazil.
Answer:
(i) Brazil experiences wide range of climatic variations due to its vast latitudinal extent, proximity to the Equator, presence of the Atlantic Ocean and the Great Escarpment.

(ii) The northern part of Brazil near the Equator is hot, while temperate type of climate is found near the Tropic of Capricorn.

(iii) Brazil gets rainfall from the South-East Trade Winds and the North-East Trade Winds blowing from the Atlantic Ocean.

(iv) Convectional rainfall occurs in places near the equator. Whereas, the Escarpment act as an obstruction to the winds blowing from the sea and cause orographic type of rainfall in the coastal region.

(v) Beyond the Highlands the effects of these winds gets reduced, as a result the rainfall is minimal. This region is a rain-shadow region and is called ‘The Drought Quadrilateral.’

(vi) The Equator passes through the northern part of Brazil so the temperature here is high. Average temperature of Amazon valley is 25°-28°C. Climate is cooler in the highlands. While the temperatures in the southern part are comparatively lower.

(vii) In the coastal regions near the Equator in Brazil, differences in temperatures are negligible. Because of the proximity to the sea, the coast experiences mild and humid climate.

(viii) The winds move in the vertical direction in this region. Similarly, the convergence zone of the trade winds is weak here. So the tropical cyclones are a rare phenomena here.

Question d.
Compare the climates of brazil and India?
Answer:

Climate of India	Climate of Brazil
(i) India has a monsoon type of climate.	(i) Brazil has a tropical climate to the north and temperate climate to the south.
(ii) The southern part of India lies in the tropical region so the temperature is high in the south and comparatively low in the north, i.e., the temperature decreases from south to north.	(ii) The northern part of Brazil lies in the tropical region so the temperature is high in the north and comparatively low in the south, i.e., the temperature decreases from north to south.
(iii) India receives rain from the South West and the North East Monsoon Winds.	(iii) Brazil receives rain from the South East and North East Trade Winds.
(iv) India receives orographic rainfall.	(iv) Brazil receives convectional and orographic type of rainfall.
(v) The western part of Rajasthan, Gujarat and eastern side of the Western Ghats receive less rain.	(v) The north eastern part of the Brazilian highlands is a rain shadow region.
(vi) Tropical cyclones are a frequent phenomena.	(vi) Tropical cyclones are a rare phenomena

Class 10 Geography Chapter 4 Climate Intext Questions and Answers

Observe the given map below and answer the following questions
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 1

Question 1.
Considering the isotherms of Brazil, what is the average range of temperature in Brazil?
Answer:
Considering the isotherms of Brazil, the average range of temperature of Brazil is 10°C (28°C-18°C).

Question 2.
In which area does it rain more?
Answer:
It rains more in the northern and central part of Brazil. E.g., Amazon Valley.

Question 3.
From which directions are winds blowing towards Brazil?
Answer:
The winds are blowing from North East and South East directions.

Question 4.
What could be the reason behind that?
Answer:
These are permanent trade winds which blow from high pressure belt to the equatorial low pressure belt. Brazil being in the tropical zone, a low pressure area is created and wind start blowing from the ocean to the land.

Question 5.
What could be the obstruction in the way of these winds?
The Escarpment acts as obstruction in the way of the South East Trade Winds coming from the sea.

Question 6.
Which type of rainfall will occur because of these winds?
Answer:
Orographic rainfall will occur because of these winds.

Question 7.
Correlate these winds and rainfall.
Answer:
The escarpments act as an obstruction to the winds blowing from the sea and cause an orographic type of rainfall in the coastal region. Beyond the Highlands, the effect of these winds gets reduced. As a result, the rainfall is minimal.

Question 8.
In which part of Brazil are the average temperatures low?
Answer:
The average temperatures are low in the southern part of Brazil.

Question 9.
Identify the rain-shadow area in Brazil. Describe its climatic characteristics.
Answer:
The north-eastern part of the Brazilian highlands is a rain shadow region. Beyond the highlands, the effect of the South East Trade Winds gets reduced and the rainfall is minimal. Also, the temperature here is quite high. This rain shadow region is referred to as the ’Drought Quadrilateral’.

Question 10.
In which region do you find a higher temperature?
Answer:
The northern part of Brazil has higher temperature.

Question 11.
Considering the latitudinal extent of Brazil, where will you find a temperate climate in Brazil?
Answer:
The southern part of Brazil lying below 23 V4°S latitude (Tropic of Capricorn) experiences temperate climate.

Question 12.
Describe the winds blowing between 0° to 5° N and S zones.
Answer:
The winds blowing between 0° to 5° N and S zones move in the vertical direction leading to convectional type of rain. The North East and South East Trade winds are very weak in this region.

Question 13.
Which method has been used to show distribution in this map?
Answer:
The Isopleth method has been used to show distribution in this map.

Observe the given map and answer the following questions
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 16

Question 1.
Which region gets more than 4000mm of rainfall?
Answer:
Western Ghats, Western Coasts of India and the northeastern region comprising of Mawsynram, Cherrapunji and parts of Assam and Arunachal Pradesh gets more than 4000 mm of rainfall.

Question 2.
Identify the regions with maximum and minimum temperatures?
Answer:
Central and North Western parts of Peninsular Plateau and islands have high temperature. Hilly regions of north, northeast and south India have low temperature.

Question 3.
In which direction is the temperature increasing?
Answer:
The temperature is increasing towards the south.

Question 4.
Identify the direction of the winds shown. What are they known as?
Answer:
The winds shown are blowing from the south west to north east direction. These winds are called Southwest Monsoon Winds.

Question 5.
Which winds are responsible for the rainfall in India ?
Answer:
South-West Monsoon Winds are responsible for rainfall in India.

Question 6.
Some part of Rajasthan is under desert? What could be the reason for it?
Answer:
The South West Monsoon Winds blow parallel to the Aravallis. As these moisture laden winds are not obstructed by the Aravallis it rains less here. Hence, Rajasthan is under desert.

Question 7.
Draw the main parallel latitude passing through India which affects its climate.
Answer:
Students are expected to draw the Tropic of Cancer.

Question 8.
In which part of Peninsular India is semi-arid climatic conditions found and why?
Answer:
(i) The part of peninsular India which has semi-arid climatic conditions are central part of Peninsula Plateau comprising parts of Central Maharashtra, Western Andhra Pradesh, Eastern Karnataka and Western Tamil Nadu. These regions lie on the leeward side of the Western Ghats and Eastern Ghats. It rains less here and a rain shadow region is formed.
(ii) Some parts of Gujarat and Rajasthan are also semi-arid as the Aravallis lie parallel and do not obstruct the South-west Monsoon winds.

Give geographical reasons:

Question 1.
Shillong gets less than 1000 mm of rainfall annually, whereas Cherrapunji/Mawsynram which is nearby get’s over 11000 mm, of rainfall annually.
Answer:
(i) Cherrapunji/Mawsynram lies in the higher altitude on the windward side of the Khasi Hills and receives rainfall from the South West Monsoon Winds.
(ii) While Shillong lies in the lower altitude on the leeward side of the Khasi Hills, so it receives less rainfall being in the rain shadow area.

Observe the pictures given below and write brief description about them.

Question 1.
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 31
Answer:
Both the figures shows the traffic congestion during heavy rains. Due to lack of proper drainage and heavy downpour the water gets accumulated disturbing the commuting system.

Question 2.
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 37

Answer:
Both the figures show the drought affected regions of India and Brazil respectively. Due to scarce amount of rainfall received in these regions the land has became dry and cannot be cultivated.

Question 3.
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 38
Answer:
figure shows snow fall during winter season in the northern parts of India.

Question 4.
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 32
Answer:
figure shows heavy rainfall in the Brazilian rainforest region.

Question 5.
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 33
Answer:
figure shows the trees being cut down to bring land under cultivation. Deforestation is a major issue in Brazil.

Question 6.
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 34
Answer:
figure shows a well from which water is used for domestic purpose.

Question 7.
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 36
Answer:
figure shows paddy fanning in India. The farmers are planting paddy. The water logged fields are shown.

Study the graphs given below and answer the following questions:

Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 14

Question 1.
In which month is the highest temperature found in all the four cities?
Answer:
The highest temperature is found in the month of January.

Question 2.
In which month does it rain the most in the given cities?
Answer:
It rains the most in the month of march.

Question 3.
When does Brazil have its rainy season?
Answer:
Brazil has its rainy season from December to march.

Question 4.
Which city has the maximum range of temperature? How much is it?
Answer:
Porto Alegre has the maximum range of temperature. It is 20°C (30° C -10° C).

Question 5.
What type of climate will be found in Rio de Janeiro?
Answer:
Rio de Janeiro has mild & humid climate.

Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 15

Question 1.
What difference do you find in the rainy seasons of Chennai and other cities of India? Why?

Rainy Season of Chennai	Rainy Seasons of Other Indian Cities
(i) Chennai mainly receives rain from October to December.	Other cities of India receive rainfall from June to September.
(ii) Chennai receives rainfall from North East Monsoon Winds.	The other cities receive rainfall mainly from South-West Monsoon Winds.

Question 2.
What similarities do you see in the temperature curves of Delhi and Kolkata?
Answer:
The following similarities can be seen in the temperature curves of Delhi and Kolkata:

The temperature rises from January to March.
From March till June high temperatures are experienced.
The temperature drops till July and remain stable in August and September.
Thereafter the temperatures decreases.

Question 3.
Calculate the average range of minimum and maximum temperatures of all the four cities.

Cities	Average range of minimum and maximum temperatures
Delhi	34°C (41°-7°)
Kolkata	28°C (37°-9°)
Mumbai	17°C (34° -17°)
Chennai	18°C (39° – 21°)

Question 4.
In which city is the range minimum? What can you infer about its climate?
Answer:
The range is minimum in Mumbai due to its proximity to the sea.

Question 5.
In which city is the range maximum? What can you infer from this about its climate?
Answer:
The range is maximum in Delhi. It indicates that Delhi has an extreme climate.

Question 6.
Based on the temperature and rainfall of Mumbai, comment upon its climate.
Answer:
Mumbai has an equable climate, with less variation in summer and winter temperature.

Question 7.
Classify the cites as cities with equable and extreme climates.
Answer:
Equable climates – Mumbai, Chennai, Kolkata. Extreme climate – Delhi.

Give it a try

Question 1.
Considering the various factors affecting Brazil’s climate, complete the table.
Answer:

Regions	Climatic characteristics
(1) Amazon Valley	The climate is generally hot and humid. It receives around 2000mm of rainfall. The average range of temperature here is 25°C – 28°C.
(2) Highlands	Hot and dry climate, low rainfall.
(3) Pantanal	Warm and humid.
(4) North Coastal region	Hot and humid climate. Rainfall between 1000 to 1200 mm.
(5) South Coastal region	Mild and humid climate.
(6) Southernmost region of Brazil	Hot summers, cool winters and snowfall.

Question 2.
In which part of India are crops grown in a year? How is this related to the rainfall over there?
Answer:
(i) Coastal areas of Tamil Nadu in India grow rice three times a year.
(ii) This crop is taken during the retreating monsoon season.
While blowing over Bay of Bengal, the North East Monsoon winds pick up moisture and give rain to eastern coast of Tamil Nadu.

Use your brain power!

Question 1.
Group the months into seasons for a whole year according to the charts given.

Seasons	India	Brazil
Summer	March to May	December to March
Winter	December to February	June to September

Answer:

Colours of Both!

Question 1.
Considering the location extent and climatic conditions of both the countries, write months according to the seasons.
Answer:

Seasons	India	Brazil
Summer	March to May	December to March
Winter	December to February	June to September

Class 10 Geography Chapter 4 Climate Additional Important Questions and Answers

Choose the correct option and rewrite the statements:

Question 1.
The climate found near the Equatorial region is
(a) hot
(b) dry
(c) humid
(d) cold
Answer:
(a) hot

Question 2.
The climate found near the Tropic of Capricorn is
(a) tropical
(b) hot
(c) temperate
(d) tundra
Answer:
(c) temperate

Question 3.
Brazil gets rainfall from
(a) North-West and South-West trade winds
(b) Westerly winds
(c) South-West and North-East
(d) North-East and South-East trade winds
Answer:
(d) North-East and South-East trade winds

Question 4.
The act as an obstruction to the winds blowing from the sea in Brazil.
(a) Himalayas
(b) Escarpments
(c) Andes
(d) Western Ghats
Answer:
(b) Escarpments

Question 5.
The coastal region of Brazil receives a type of rainfall.
(a) orographic
(b) cyclonic
(c) convectional
(d) frontal
Answer:
(a) orographic

Question 6.
Since the convergence of trade winds are weak near the equator, are not formed.
(a) clouds
(b) ocean currents
(c) cyclones
(d) tides
Answer:
(c) cyclones

Question 7.
The average temperature in the Amazon valley is
(a) 15°-20°C
(b) 13°-15°C
(c) 30°-32°C
(d) 25°-28°C
Answer:
(d) 25°-28°C

Question 8.
The Amazon valley receives around mm of rainfall
(a) 2000
(b) 1800
(c) 1500
(d) 1000-1200
Answer:
(a) 2000

Question 9.
India’s climate is of type.
(a) humid
(b) monsoon
(c) equatorial
(d) cold
Answer:
(b) monsoon

Question 10.
The diversity in the climatic conditions of India is due to the location and altitude of the place.
(a) longitudinal
(b) latitudinal
(c) equatorial
(d) tropical
Answer:
(b) latitudinal

Question 11.
The Ocean and the Himalayan ranges exert a great influence on the climate of India.
(a) Atlantic
(b) Arctic
(c) Pacific
(d) Indian
Answer:
(d) Indian

Question 12.
Orographic type of rainfall occurs in India because of the natural obstruction of
(a) Himalayas
(b) Escarpments
(c) Highlands
(d) Satpuda
Answer:
(a) Himalayas

Question 13.
As the passes through the middle of India, it is considered to be a tropical region.
(a) Tropic of Capricorn
(b) Equator
(c) Tropic of Cancer
(d) 60°S latitude
Answer:
(c) Tropic of Cancer

Question 14.
Most part of Brazil lies in the zone.
(а) polar
(b) tropical
(c) sub-tropical
(d) temperate
Answer:
(b) tropical

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
(1) Wettest places in the world	(a) Tamil Nadu
(2) Driest place in India	(b) Cherrapunji and Mawsynram
(3) Rainshadow region in Brazil	(c) Jaisalmer, Rajasthan
(4) Climate of India	(d) Drought Quadrilateral (e) Monsoon type (f) Dry type

Answer:
1 – b
2 – c
3 – d
4 – e

Answer in one sentence each.

Question 1.
Which natural disasters does India face frequently?
Answer:
India frequently faces natural disasters like erratic rainfall, droughts, cyclones, floods, etc.

Question 2.
Why does Brazil experience wide climatic variations?
Answer:
Brazil has vast latitudinal extent because of which it experiences wide climatic variations.

Question 3.
Which winds bring rainfall to Brazil?
Answer:
Brazil receives rainfall from the South East and North-East Trade Winds.

Question 4.
What acts as an obstruction to the winds blowing from sea in Brazil?
Answer:
The Escarpments act as an obstruction to the winds blowing from the sea in Brazil.

Question 5.
Which region is called the Drought Quadrilateral’?
Answer:
The northern part of Brazil beyond the Highlands is called ‘Drought Quadrilateral’.

Question 6.
Where is the difference in temperature negligible in Brazil?
Answer:
In Brazil the difference in temperature is negligible in the coastal regions near the equator.

Question 7.
In which zone does most of Brazil and India lie?
Answer: Most part of Brazil and India lies in the Tropical zone.

Question 8.
Which important latitude passes through the northern part of Brazil?
Answer:
The equator passes through the northern part of Brazil.

Question 9.
What is the average temperature in Amazon valley?
Answer:
The average temperature in Amazon valley is 25°-28°C.

Question 10.
Which part of Brazil has cooler climate?
Answer:
The climate is cooler in the Highlands.

Question 11.
Why do the Brazilian coasts experience mild and humid climate?
Answer:
The Brazilian coasts experience mild and humid- climate because of its proximity to sea.

Question 12.
Which type of climate is found in India?
Answer:
Monsoon type of climate is found in India.

Question 13.
Which important latitude passes through the middle of India?
Answer:
The Tropic of Cancer passes through the middle of India.

Question 14.
What diversifies the climatic conditions of India?
Answer:
The diversity in the climatic conditions of India are due to the latitudinal location and altitude of India.

Question 15.
What exerts a great influence on the climate of India and the origins of the monsoon?
Answer:
The Indian Ocean and the Himalayan ranges exert a great influence on the climate of India and the origin of monsoons.

Question 16.
In India, what obstructs the cold winds blowing from the North?
Answer:
In India, the Himalayas obstruct the cold winds blowing from the north.

Question 17.
What brings more rain in the coastal regions of India?
Answer:
The obstruction caused by the Eastern and Western Ghats brings more rain in the coastal regions of India.

Question 18.
Find out more about the different ways of classification of the seasons. For example, what is summer?
Answer:
The hot weather season is called summer. The season where the rain begins is called the monsoon. The cold weather season is called winter.

Name the following:

Question 1.
The two places in India which are considered as the wettest places in the world.
Answer:
Cherrapunji and Mawsynram.

Question 2.
Years in which Brazil has experienced snowfall.
Answer:
1879,1957and 1985.

Question 3.
The driest part of India.
Answer:
Jaisalmer, Rajasthan.

Question 4.
The state in India which receives maximum rainfall during the retreating monsoon season.
Answer:
Tamil Nadu.

Question 5.
Temperature in Kargil in winter.
Answer:
-48°C.

Question 6.
Temperature in Ganganagar, Rajasthan in the month of June.
Answer:
50°C.

Question 7.
The hills responsible for heavy rainfall in Cherrapunji and Mawsynram.
Answer:
Garo, Khasi and Jaintia Hills.

Question 8.
The winds which provide rainfall to the Tamil Nadu coast.
Answer:
North East Monsoon winds.
Question 9.
The state to receive rain foremost in India.
Answer:
Kerala.

Question 10.
The four seasons of India as per Indian meteorological department.
Answer:
The hot weather season (Summer), the season

Are the sentences right ot wrong? Rewrite the wrong ones.

Question 1.
Brazil experiences wide climatic variation due to its vast longitudinal extent.
Answer:
Wrong – Brazil experiences wide climatic variation due to its vast latitudinal extent.

Question 2.
The winds move in the vertical direction in northern Brazil.
Answer:
Right.

Question 3.
The rainfall reduces on the windward side of the Great Escarpment.
Answer:
Wrong – The rainfall increases on the windward side of the Great Escarpment.

Mark the following on the map with the given information and make an index.

Question 1.
Outline Map of Brazil.

Winds bringing rainfall to Brazil or North East and South East Trade winds.
Drought Quadrilateral or Rainshadow region in Brazil.

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 18

Question 2.
Outline Map of India.

Southwest Monsoon winds or winds bringing rainfall to most parts of India.
Northeast monsoon winds.
Kargil or place recording lowest temperature in India.
Cherrapunji and Mawsynram.
Coromandel coast or the coast receiving rainfall from North East monsoon winds.
Jaisalmer or place recording lowest rainfall in India.
Rain shadow region of Deccan plateau.
Region of low rainfall.
Heavy rainfall region along the western coast.

Answer:
Maharashtra Board Class 10 Geography Solutions Chapter 4 Climate 20

10th Std Geography Questions And Answers:

Introduction to Acid and Base Class 8 Science Chapter 12 Questions And Answers Maharashtra Board

February 6, 2025February 5, 2025 by Bhagya

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 12 Introduction to Acid and Base Notes, Textbook Exercise Important Questions and Answers.

Std 8 Science Chapter 12 Introduction to Acid and Base Question Answer Maharashtra Board

Class 8 Science Chapter 12 Introduction to Acid and Base Question Answer Maharashtra Board

1. Identify the following solutions, whether they are acid or base.

Question a.

Answer:

2. Write chemical names from given formulae.
H₂SO₄, Ca(OH)₂, HCl, NaOH, KOH, NH₄OH

Question a.
Write the chemical names from given formulae: H₂SO₄, Ca(OH)₂, HCl, NaOH, KOH, NH₄OH
Answer:

H₂SO₄ – Sulphuric acid
Ca(OH)₂ – Calcium hydroxide
HCl – Hydrochloric acid
NaOH – Sodium hydroxide
KOH – Potassium hydroxide
NH₄OH – Ammonium hydroxide

3. Sulphuric acid has highest importance in chemical Industry. Why?

Question a.
Sulphuric acid has highest importance in chemical Industry. Why?
Answer:
Answer:
Sulphuric acid has highest importance in the chemical industry because it is used in the manufacturing of fertilizers like ammonium sulphate and superphosphate of lime. It is used in the manufacturing of hydrochloric acid, nitric acid, phosphoric acid, ether, plastics and metal sulphates. It is also used in the manufacturing of dyes, drugs, perfumes, disinfectants and glue.

4. Give answers.

Question a.
Which acid is used for getting chloride salt?
Answer:
Hydrochloric acid is used for getting chloride salt.

Question b.
By squeezzing lemon on a piece of rock the gas liberated turned lime water milky. Which compound is present in the rock?
Answer:
Metal carbonate is present in the rock.

Question c.
The label on the bottle of chemical is spoiled. How will you find whether the chemical is acidic or not?
Answer:
The chemical is tested with blue litmus paper. If it turns red it is an acidic otherwise tested with red litmus paper, if it turns blue, it is an alkaline.

5. Answer the following questions.

Question a.
Explain the difference between acid and base.
Answer:
Acids:

Acids have sour taste.
Acids turn blue litmus red.

Bases:

Bases have bitter taste.
Bases turn red litmus blue.

Question b.
Why indicator does not affect by salt?
Answer:
Mostly indicators are organic compounds which do not react with a salt.

Question c.
Which substances are produced i by neutralization process?
Answer:
Salt and water are produced in the f neutralization process.

Question d.
Which are the industrial uses of acids?
Answer:
Acids which are used in the industry are:

Sulphuric acid
Hydrochloric acid
Nitric acid.;

1. Sulphuric acid: Sulphuric acid is 5 used (a) in the manufacture of chemical? fertilizers like ammonium sulphate, (b) for cleaning gold and silver articles and (c) in car batteries.

2. Hydrochloric acid: Hydrochloric acid is used (a) to clean toilets and (b) to obtain glucose from starch and also for producing gelatine.

3. Nitric acid: Nitric acid is used (a) in the manufacture of perfumes (b) for engraving on copper, brass or silver and (c) in the manufacture of paints and explosives.

6. Select proper word given in bracket and fill in the blanks.

Question a.
Main constituent of acid is ……………. .
Answer:
Main constituent of acid is H⁺ ion.

Question b.
Main constituent of alkali is …………….. .
Answer:
Main constituent of alkali is OH^– ion.

Question c.
Tartaric acid is a …………… acid.
Answer:
Tartaric acid is a weak acid.

7. Match the pairs.

Question a.

Group A	Group B
1. Tamarind	a. Acetic acid
2. Curd	b. Citric acid
3. Lemon	c. Tartaric acid
4. Vinegar	d. Lactic acid

Answer:

Group A	Group B
1. Tamarind	c. Tartaric acid
2. Curd	d. Lactic acid
3. Lemon	b. Citric acid
4. Vinegar	a. Acetic acid

8. State true or false.

Question a.
Oxides of metals are alkaline in nature.
Answer:
True.

Question b.
Salt is acidic.
Answer:
False. (Salt is neutral)

Question c.
Metal corrodes due to salts.
Answer:
False. (Acids and bases corrode metals)

Question d.
Salts are neutral.
Answer:
True. (Not all salts neutral)

9. Classify the following substances into acidic, basic and neutral group:
HCl, NaCl, MgO, KCl, CaO, H₂SO₄, HNO₃, H₂O and Na₂CO₃.

Question a.
Classify the following substances into acidic, basic and neutral group:
HCl, NaCl, MgO, KCl, CaO, H₂SO₄, HNO₃, H₂O and Na₂CO₃.
Answer:

Group	Substances
Acid	HCl, H₂SO₄, HNO₃
Base	CaO, MgO, Na₂CO₃
Neutral	H₂O, NaCl, KCl.

Project:

Question a.
Write in your own language the uses and importance of neutralization reaction in daily life.

Class 8 Science Chapter 12 Introduction to Acid and Base Important Questions and Answers

Fill in the blanks:

Question 1.
Acid reacts with metal to form …………. gas.
Answer:
Acid reacts with metal to form hydrogen gas.

Question 2.
DNA is an acid present in our body, it decides …………. properties.
Answer:
DNA is an acid present in our body, it decides heredity properties.

Question 3.
The chemical formula of milk of magnesia is ………….
Answer:
The chemical formula of milk of magnesia is Mg (OH)₂.

Question 4.
…………. are used to control hyperacidity.
Answer:
Antacids are used to control hyperacidity.

Question 5.
Alkali has …………. taste.
Answer:
Alkali has bitter taste.

Question 6.
Proteins are made up of ………….
Answer:
Proteins are made up of amino acids.

Question 7.
…………. is used in batteries.
Answer:
Dil. H₂SO₄ is used in batteries.

Rewrite the following statements by selecting the correct options:

Question 1.
The colour of phenolphthalein indicator in alkaline solution is ………….
(a) yellow
(b) green
(c) orange
(d) pink
Answer:
The colour of phenolphthalein indicator in alkaline solution is pink.

Question 2.
…………. is sour to taste.
(a) An acid
(b) An alkali
(c) A salt
(d) Alcohol
Answer:
An acid is sour to taste.

Question 3.
When phenolphthalein is added to NaOH, the colour of the solution will become ……………… .
(a) colourless
(b) red
(c) pink
(d) yellow
Answer:
When phenolphthalein is added to 5 NaOH, the colour of the solution will become pink.

Question 4.
When phenolphthalein is added to HCl, the colour of the solution will be ………….. .
(a) red
(b) pink
(c) green
(d) colourless
Answer:
When phenolphthalein is added to HCl, the colour of the solution will be colourless.

Question 5.
…………. is a natural indicator.
(a) Phenolphthalein
(b) Methyl orange
(c) Litmus
(d) Methyl red
Answer:
Litmus is a natural indicator.

Question 6.
The litmus paper or the litmus solution is obtained from …………. plants.
(a) moss
(b) rose
(c) hibiscus
(d) lichen
Answer:
The litmus paper or the litmus solution is obtained from lichen plants.

Question 7.
…………. is not an alkali.
(a) Sodium hydroxide
(b) Potassium hydroxide
(c) Copper hydroxide
(d) Calcium hydroxide
Answer:
Copper hydroxide is not an alkali.

Question 8.
…………. is a weak acid.
(a) Hydrochloric acid
(b) Nitric acid
(c) Carbonic acid
(d) Sulphuric acid
Answer:
Carbonic acid is a weak acid.

Question 9.
When methyl orange is added to HCl, the colour of the solution will be …………… .
(a) red
(b) pink
(c) yellow
(d) colourless
Answer:
When methyl orange is added to HCl, the colour of the solution will be pink.

Question 10.
When blue litmus paper is added to NaOH, the colour of the litmus paper will be ……………. .
(a) blue
(b) red
(c) pink
(d) yellow
Answer:
When blue litmus paper is added to NaOH, the colour of the litmus paper will be blue.

State whether the following statements are true or false. If a statement is false, correct it and rewrite:

Question 1.
Red cabbage is a natural indicator.
Answer:
True

Question 2.
Fats of our body are formed by fatty acids.
Answer:
True.

Question 3.
Ammonium hydroxide is used in the production of fertilizers.
Answer:
True.

Question 4.
Lime water is a weak acid.
Answer:
False. (Limewater is a weak base)

Question 5.
Orange colour of methyl orange turns yellow in acid.
Answer:
False. (Orange colour of methyl orange turns pink in acid)

Question 6.
Methyl red turns yellow in alkali.
Answer:
True.

Question 7.
Oxalic acid is used in aerated cold drinks.
Answer:
False. (Carbonic acid is used in aerated cold drinks).

Find the odd one out and justify:

Question 1.
Acetic acid, carbonic acid, hydrochloric acid, nitric acid.
Answer:
Acetic acid. (Others are mineral acids.)

Question 2.
Hydrogen chloride, sodium hydroxide, calcium oxide, ammonia.
Answer:
Hydrogen chloride. (Others are bases.)

Question 3.
HCl, CH₃COOH, H₂SO₄, HNO₃
Answer:
CH₃COOH. (Others are strong acids.)

Question 4.
NaOH, Ca(OH)₂, NH₄OH, Ba(OH)₂
Answer:
NaOH (Others are weak bases.)

Question 5.
H₂SO₄, H₂CO₃, HCl, HNO₃
Answer:
H₂CO₃ (Others are strong acids.)

Question 6.
Citric acid, formic acid, lactic acid, nitric acid.
Answer:
Nitric acid. (Others are organic acids.)

Question 7.
Lime, litmus, phenolphthalein, methyl orange.
Answer:
Lime. (Others are indicators.)

Match the following:

Question 1.

Column ‘A’	Column ‘B’
1. Strong acid	a. Magnesium hydroxide
2. Weak alkali	b. Carbonic acid
3. Weak acid	c. NaOH
4. Strong alkali	d. Nitric acid

Answer:

Column ‘A’	Column ‘B’
1. Strong acid	d. Nitric acid
2. Weak alkali	a. Magnesium hydroxide
3. Weak acid	b. Carbonic acid
4. Strong alkali	c. NaOH

Question 2.

Column ‘A’	Column ‘B’
1. Sodium hydroxide	a. Whitewashing
2. Magnesium hydroxide	b. Fertilizers
3. Calcium hydroxide	c. Washing soap
4. Ammonium hydroxide	d. Antacid

Answer:

Column ‘A’	Column ‘B’
1. Sodium hydroxide	c. Washing soap
2. Magnesium hydroxide	d. Antacid
3. Calcium hydroxide	a. Whitewashing
4. Ammonium hydroxide	b. Fertilizers

Define the following:

1. Acid: A substance which gives H⁺ ions in water is called an acid.

2. Alkali: A substance which gives OH^– ions in water is called an alkali.

3. Indicator: Substances which change their colours in presence of acid or base are called indicators.

4. Neutralization: The reaction between an acid and an alkali to form the r salt and water is termed as neutralization.

Answer the following questions in one sentence each:

Question 1.
What are natural acids?
Answer:
Acids present in foodstuffs are called natural acids.

Question 2.
State three vegetables from which natural indicators can be prepared.
Answer:
Natural indicators: Red cabbage, radish, tomato.

Question 3.
State names of any three strong acids.
Answer:

Hydrochloric acid
Sulphuric acid
Nitric acid.

Question 4.
State the names of the acids found in lemon juice, Amla, tamarind water and curd.
Answer:

Lemonuice – citric acid
Amla – ascorbic acid
tamarind water – tartaric acid
curd – lactic acid.

Question 5.
State names of any three alkalis.
Answer:

sodium hydroxide
potassium hydroxide
calcium hydroxide.

Question 6.
State the names of three indicators.
Answer:

Litmus paper
Methyl orange
Phenolphthalein.

Question 7.
State the names of three weak alkalis.
Answer:

Calcium hydroxide
ammonium hydroxide
magnesium hydroxide.

Question 8.
From which plant is litmus obtained?
Answer:
Litmus is obtained from plants called lichens.

Question 9.
Name the antacid which is used to control the hyper acidity.
Answer:
Milk of magnesia [Mg(OH)₂] is used to control the hyper acidity.

Question 10.
How will you neutralize the excess of acid present in the soil?
Answer:
Lime stone or lime water is mixed in the soil to neutralize the excess of acid.

Question 11.
When lemonuice falls on a marble kitchen counter, which is the gas that bubbled out?
Answer:
Carbon dioxide.

Answer the following questions:

Question 1.
What are indicators?
Answer:
Substances which change their colours in presence of acid or base are called indicators.

Question 2.
State two acid-base indicators and mention their colour change.
Answer:
Phenolphthalein and methyl orange are two acid-base indicators. Phenolphthalein is colourless in an acidic solution while it turns pink in a basic solution. Methyl orange gives orange colour with an acidic solution and yellow colour with a basic solution.

Question 3.
State the colour change for each of the following solutions with red litmus, blue litmus, phenolphthalein and methyl orange solutions.
Answer:

Question 4.
Name the acid present in (1) Orange (2) Vinegar (3) Tamarind (4) Curd (5) Tomato (6) Lemon.
Answer:

Substance	Acid
Orange	Citric acid
Vinegar	Acetic acid
Tamarind	Tartaric acid
Curd	Lactic acid
Tomato	Oxalic acid
Lemon	Citric acid

Question 5.
Classify the following into acidic substances, basic substances and salts.
(1) Lime water, (2) soda water, (3) soap water, (4) sea water, (5) sweet limeuice, (6) sugar caneuice, (7) buttermilk, (8) a mixture of ash in water, (9) tamarind water.
Answer:
a. Acidic substances: (1) Soda water, (2) sweet limeuice, (3) buttermilk, (4) tamarind water.
b. Basic substances: (1) Lime water, (2) Soap water, (3) a mixture of ash in water.
c. Salts: (1) Sea water, (2) sugar caneuice.

Question 6.
What happens when sour substances like limeuice, tamarind water falls on shahabad stones or kitchen platform? Why?
Answer:
When sour substances like limeuice, tamarind water falls on shahabad stones or kitchen platform, citric acid present in limeuice and tartaric acid in tamarind water reacts with metal carbonates present in shahabad stones or kitchen platform, carbon dioxide gas is evolved resulting in the formation of uneven surface.

Question 7.
Collect soil samples from your surroundings and find out whether it is acidic or alkaline or neutral?
Answer:
Soil samples collected from the surroundings are acidic in nature.

Question 8.
Which substances are used to clean greenish stains on copper vessels and to shine blackish silver utensils?
Answer:
Tamarind pulp is used to clean greenish stains on copper vessels. To shine blackish silver utensils, ammoniacal solution or limeuice or detergent is used.

Question 9.
Why toothpaste is used for brushing teeth?
Answer:

Toothpaste contains fluorides and alkali to neutralize the mouth acid.
Hence, the tooth paste, which is generally alkaline, is used for cleaning the teeth as it can neutralize the excess acid in i the mouth and prevent tooth decay.

Question 10.
State the properties of acids.
Answer:

Acids are sour in taste.
Acid molecules contain hydrogen ion (H⁺) as a main constituent.
Acid reacts with metal to form hydrogen gas.
Acid reacts with carbonates and liberates CO₂ gas.
Blue litmus turns red in acid.

Question 11.
State the uses of acids.
Answer:

Acids are used in the production s of chemical fertilizers.
Acids are used in the production of explosives, oil purification, medicines, dyes and paints.
Hydrochloric acid is used for the preparation of different types of chloride salts.
Dil. H₂SO₄ acid is used in the batteries (electric cell).
Dil. HCl is used for sterilization of water.
Acid is used for making of white paper from wood pulp.

Question 12.
The iron knife shines better after cutting the sour fruits like lemon, raw mangoes. Why?
Answer:
Acids present in sour fruits clean and dissolves the salts present on the surface of iron knife as a result iron knife shines better after cutting the sour fruits.

Question 13.
What is meant by neutralization? Give example.
Answer:
When an acid reacts with an alkali to form a salt and water, it is called neutralization.

Give scientific reasons:

Question 1.
When we have stomachache, doctors prescribe medicine containing magnesium hydroxide.
Answer:

There is hydrochloric acid in our stomach which helps in the digestion of food.
Sometimes in the stomach, there is more hydrochloric acid than we need.
This excess acid causes acidity and indigestion resulting in stomachache.
When magnesium hydroxide is administered it neutralizes the extra acid in the stomach.
Therefore, magnesium hydroxide is the best cure for stomachache.
So, when we have stomachache, doctors prescribe medicine containing magnesium hydroxide.

Question 2.
Quicklime or slaked lime is added to the soil.
Answer:

When chemical fertilizers are added to the soil, the soil becomes acidic.
To reduce its acidity quicklime or slaked lime is added to the soil.

Question 3.
Tarnished and stained copper vessels are brought to a shine by using tamarind pulp.
Answer:
In due course, unus6d copper vessels
are covered with a coating of black copper oxide and other compounds of copper which tarnish the vessel. Tamarind contains tartaric acid. When the vessel is rubbed with tamarind pulp, tartaric acid reacts with copper oxide and removes the layer. Thus, the copper vessel regains its shine.

Question 4.
Copper and brass utensils are tinned.
Answer:
Copper and brass reacts with i organic acids present in food materials and poisonous salts are formed. Tin does not react with organic acids present in food materials. Therefore, copper or brass vessels are tinned.

Distinguish between acid and alkali. OR Distinguish between the following:

Question 1.
Acid and Alkali:
Answer:

Acid	Alkali
1. Acid has sour taste.	1. Alkali has bitter taste.
2. Acid turns blue litmus red.	2. Alkali turns red litmus blue.
3. An acid in an aqueous solution gives H⁺ ions.	3. An alkali in an aqueous solution gives OH⁺ ions.
4. Oxides of non – metals form acids.	4. Oxides of metals form bases.

Activity-based questions:

Activity 1:
Apparatus: Hibiscus, rose, turmeric, red cabbage leaves, filter paper, etc.
Activity: Rub red petals of hibiscus flower on the white filter paper. This gives hibiscus indicator paper. Similarly rub, rose petals on the white filter paper. Cut strips of this paper, it is a rose indicator paper. Take turmeric powder, add a little water in it. Dip filter paper or ordinary paper in the turmeric water for some time.

After drying make strips of that paper. Prepare turmeric indicator paper in this way. Put leaves of red cabbage in small quantity of water and heat it. Once solution of cabbage leaves cool down, dip papers in it and dry it. Make strips of dried paper. In this way prepare red cabbage indicator paper. Put some drops of following substances on the indicator papers prepared by the above method and write the effect in the following table:

Substance	Effect on turmeric paper	Acidic/basic
1. Lime juice	Yellow	Acidic
2. Lime water (calcium hydroxide)	Red	Basic
3.

Activity 2:
Take baking powder. Add a little water to it. Add this solution on to limeuice, vinegar, orangeuice, appleuice, etc. and note the findings.
What do you observe on addition of baking soda solution in the fruituice? Whether bubbles formed or effervescence came out of fruituice?
From the above first activity we came to know that yellow turmeric indicator paper’s turns red in certain solutions. Similarly on addition of baking soda solution in the acidic solution bubbles come out or effervescence is produced.
By these simple and easy activity we can identify acidic or alkaline substance:
[Note for Activity 1 and Activity 2: Students should perform the experiments under the guidance of school teachers and record their observations.]

Activity 3:
Under the guidance of teacher take limeuice, ammonium hydroxide (NH₄OH), dil. hydrochloric acid (dil. HCl) and nitric acid (HNOs) in different test-tubes. Add drops of following indicators in them. Also dip litmus papers in the solutions. Observe and record in the following table.

8th Std Science Questions And Answers:

Metals and Nonmetals Class 8 Science Chapter 7 Questions And Answers Maharashtra Board

February 6, 2025February 5, 2025 by Bhagya

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 7 Metals and Nonmetals Notes, Textbook Exercise Important Questions and Answers.

Std 8 Science Chapter 7 Metals and Nonmetals Question Answer Maharashtra Board

Class 8 Science Chapter 7 Metals and Nonmetals Question Answer Maharashtra Board

1. Complete the table:

Question a.

Answer:

Property of metal	Use in everyday life
i. Ductility	i. Gold, silver ornaments
ii. Malleability	ii. Aluminium sheets, galvanised sheets
iii. Conduction of heat	iii. Stainless steel vessels, copper vessels, boilers
iv. Conduction of electricity	iv. Copper wires
v. Sonority	v. Brass articles

2. Identify the odd term.

Question a.
Gold, Silver, Iron, Diamond.
Answer:
Diamond. (Others are metals.)

Question b.
Ductility, Brittleness, Sonority, Malleability.
Answer:
Brittleness. (Other properties are metallic properties.)

Question c.
Carbon, Bromine, Sulphur, Phosphorus.
Answer:
Bromine. (Others are solids.)

Question d.
Brass, Bronze, Iron, Steel.
Answer:
Iron. (Others are alloys.)

3. Give scientific reasons:

Question a.
The stainless steel vessels in kitchen have copper coating on the bottom.
Answer:

Stainless steel is an alloy of iron ; with carbon, chromium and nickel.
The conductivity of copper is higher than that of iron in steel. Copper heats uniformly and faster. The time for cooking is reduced, as a result it saves fuel. Hence, the stainless steel vessels in kitchen have copper coating on the bottom.

Question b.
Copper and brass vessels are cleaned with lemon.
Answer:

Copper undergoes oxidation in air to form black copper oxide. Copper oxide reacts slowly with carbon dioxide in air and gains a green coat. This green substance is copper carbonate.
Lemon contains acid. The acid dissolves the green coating of basic copper carbonate present on the surface of a tarnished copper and brass vessels and makes them shiny again.

Question c.
Sodium metal is kept in kerosene.
Answer:

Sodium reacts so vigorously with atmospheric oxygen and water that it catches fire if kept in the open.
It does not react with kerosene and sinks in it. Hence, to protect sodium and to prevent accidental fires it is always kept in kerosene.

4. Answer the following:

Question a.
What is done to prevent corrosion of metals?
Answer:
By applying a layer of paint, oil, grease or varnish on the surface of a metal to prevent corrosion. Also plating with noncorroding metal is done. Iron is coated with thin layer of zinc. Due to these processes the contact of metal surface with air is lost and corrosion is prevented.

Question b.
What are the metals that make the alloys brass and bronze?
Answer:
The alloy brass is formed from copper and zinc and the alloy bronze is formed from copper and tin.

Question c.
What are the adverse effects of i corrosion?
Answer:

A reddish coloured deposit (rust) is formed on iron by reaction with oxygen gas.
A greenish coloured deposit (copper carbonate) is formed on copper by reaction with carbon dioxide.
A blackish coloured deposit is formed (silver sulphide) on silver.
Corrosion causes damages to car bodies, bridges, iron railings, ships specially those of iron, silver articles and copper vessels.

Question c.
What are the uses of noble metals?
Answer:
Uses of Noble Metals:

Gold, silver and platinum are used to prepare ornaments.
Silver is used in medicines. (It has antibacterial property).
Gold and silver are also used to make metals and few electronic devices.
Platinum, palladium metals are used as catalyst.

5. Three experiments to study the process of rusting are given below. Observe the three test tubes and answer the following questions.

Question a.
Why the nail in the test tube 2 is not rusted?
Answer:
In the test tube 2, oil cuts the supply of air to nail due to which oxidation of nail is prevented and boiled water is free from gases. Hence, the nail in the test tube 2 is not rusted.

Question b.
Why is the nail in the test tube 1 is rusted highly?
Answer:
The nail in the test tube 1 is highly rusted because nail is in contact with water and air. The oxidation process is fast.

Question c.
Would the nail in the test tube 3 get rusted?
Answer:
No change is observed in the test tube 3. Nail remains as it is because the calcium chloride absorbs moisture, making the air dry, thus preventing rusting of the nail.

Project:

Question a.
How is the Varkha or silver foil used in sweets made? Collect the information about which metals are used to make ‘Varkha’.

Class 8 Science Chapter 7 Metals and Nonmetals Additional Important Questions and Answers

Rewrite the sentences after filling the blanks:

Question 1.
Gold of 100% purity is …………… carat gold.
Answer:
Gold of 100% purity is 24 carat gold.

Question 2.
The stainless steel utensils used at home are made of an alloy of iron with carbon, …………… and ……….. .
Answer:
The stainless steel utensils used at home are made of an alloy of iron with carbon, nickel and chromium.

Question 3.
…………….. is used in medicines.
Answer:
Silver is used in medicines.

Question 4.
To prepare ornaments ………… carat gold is used.
Answer:
To prepare ornaments 22 carat gold is used.

Question 5.
Non-metals are ………… conductors of heat and electricity.
Answer:
Non-metals are bad conductors of heat and electricity.

Question 6.
Non-metals form ………….. oxides.
Answer:
Non-metals form acidic oxides.

Question 7.
Some element can be hammered into thin sheets. This property is called …………….. .
Answer:
Some element can be hammered into thin sheets. This property is called malleability.

Question 8.
Iodine and ……………. are the two non – metals having typical metallic lustre.
Answer:
Iodine and diamond are the two non¬metals having typical metallic lustre.

Question 9.
Non-metals form ………. ions by gain of electrons.
Answer:
Non-metals form negative ions by gain of electrons.

Question 10.
During formation of positively charged ion, atom of metal ………….. .
Answer:
During formation of positively charged ion, atom of metal lose electrons.

Rewrite the following statements by selecting the correct options:

Question 1.
Metalloids have properties of …………. .
(a) metals
(b) non-metals
(c) both metals and non-metals
(d) neither metals nor non-metals
Answer:
(c) both metals and non-metals

Question 2.
………….. is a metal.
(a) Hg
(b) S
(c) P
(d) Br
Answer:
(a) Hg

Question 3.
…………… is a non-metal.
(a) Aug
(b) Ag
(c) Br
(d) Cu
Answer:
(c) Br

Question 4.
……………. is a metalloid.
(a) Aluminium
(b) Antimony
(c) Zinc
(d) Mercury
Answer:
(b) Antimony

Question 5.
……………. is a metal which is in liquid form at ordinary temperature.
(a) Gallium
(b) Magnesium
(c) Sodium
(d) Scandium
Answer:
(a) Gallium

Question 6.
…………….. is an acidic oxide.
(a) Na₂O
(b) CO₂
(c) FeOs
(d) H₂O
Answer:
(b) CO₂

Question 7.
The valence electron in …………… atom is 1.
(a) magnesium
(b) sodium
(c) silicon
(d) aluminium
Answer:
(b) sodium

Question 8.
The electronic configuration of oxygen is …………….. .
(a) 2, 5
(b) 2, 6
(c) 2, 4
(d) 2, 8, 6
Answer:
(b) 2, 6

Question 9.
Pure ………… is soft.
(a) aluminium
(b) silver
(c) gold
(d) platinum
Answer:
(c) gold

Question 10.
…………… is a highly malleable metal.
(a) Iron
(b) Nickel
(c) Manganese
(d) Aluminium
Answer:
(d) Aluminium

Question 11.
22 carat gold is gold of …………… purity.
(a) 100%
(b) 91.66%
(c) 75%
(d) 44%
Answer:
(b) 91.66%

State whether the following statements are True or False:

Question 1.
Metals are sonorous.
Answer:
True.

Question 2.
Diamond is the softest natural substance.
Answer:
False. (Diamond is the hardest natural substance.)

Question 3.
The density of lithium is lower than water.
Answer:
True.

Question 4.
Sulphur is brown in colour.
Answer:
False. (Sulphur is yellow in colour.)

Question 5.
Germanium is a metalloid.
Answer:
True.

Question 6.
Ornaments are made from 24 carat gold.
Answer:
False. (Ornaments are made from 22 carat gold.)

Question 7.
A reddish coloured deposit is formed on iron by reaction with oxygen.
Answer:
True.

Question 8.
Paladium and rhodium are noble metals.
Answer:
True.

Question 9.
The metal oxides are acidic in nature.
Answer:
False. (The metal oxides are basic in nature.)

Question 10.
The metal reacts with dilute acids to form a metal salt.
Answer:
True.

Identify the odd term:

Question 1.
Magnesium, Mercury, Sodium, Iron.
Answer:
Mercury. (Others metals are in solid state at normal temperature.)

Question 2.
Magnesium, Aluminium, Sulphur, Copper.
Answer:
Sulphur. (Others are metals.)

Question 3.
Iron, Copper, Graphite, Phosphorus.
Answer:
Phosphorus. (Others are good conductors of electricity.)

Question 4.
Tin, Bronze, Steel, Stainless steel.
Answer:
Tin. (Others are alloys.)

Consider the relation between the items in the first pair and write the correlation for second pair:

Question 1.
Mercury : Metal : : Carbon : …………. .
Answer:
Non-metal

Question 2.
Wood : Bad conductor of electricity : : Copper : ………………… .
Answer:
Good conductor or electricity

Question 3.
Gold : Noble metal : : Copper: ……………. .
Answer:
Metal

Question 4.
Iron and carbon : Steel : : Copper and Tin : ……….. .
Answer:
Bronze

Question 5.
0 : 2, 6 : : Mg : …………….. .
Answer:
2, 8, 2.

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
1. Copper	a. Low melting point
2. Sodium	b. Liquid
3. Magnesium	c. High melting point
4. Boron	d. Conduction of heat
	e. 2, 8, 2

Answer:

Column ‘A’	Column ‘B’
1. Copper	d. Conduction of heat
2. Sodium	a. Low melting point
3. Magnesium	e. 2, 8, 2
4. Boron	c. High melting point

Question 2.

Column ‘A’	Column ‘B’
1. Silver	a. Copper + tin
2. Mercury	b. Medicines
3. Platinum	c. Thermometer
4. Brass	d. Catalyst

Answer:

Column ‘A’	Column ‘B’
1. Silver	b. Medicines
2. Mercury	c. Thermometer
3.Platinum	d. Catalyst
4. Brass	a. Copper + tin

Define the following:

Ductility: The property due to which a substance can be drawn into a thin wire is called ductility.
Malleability: The property due to which a substance can be hammered into a thin sheet is called malleability.
Metalloids: The element which shows the properties of metals as well as those of non-metals is called a metalloid.
Corrosion: Gases in the air react with metals in presence of moisture to form metal compounds on its surface, this destroys the metal gradually and is called corrosion.
Alloy: A homogeneous mixture of two or more metals or a homogeneous mixture of metal with non-metals is called alloy.

Answer the following questions in one sentence:

Question 1.
Name an alloy of copper and tin.
Answer:
An alloy of copper and tin is termed as bronze.

Question 2.
Name a metal which is in liquid state at ordinary temperature.
Answer:
Mercury is in liquid state at ordinary temperature.

Question 3.
Name two metals which are malleable.
Answer:
Iron and aluminium are malleable metals.

Question 4.
Name two metals which are ductile.
Answer:
Gold and silver are ductile metals.

Question 5.
Name two metals which are good conductors of heat.
Answer:
Silver and copper are good conductors of heat.

Question 6.
Name two metals which are good conductors of electricity.
Answer:
Copper and aluminium are good conductors of electricity.

Question 7.
Name two non-metals which are in solid state at room temperature.
Answer:
Carbon and sulphur are solids at room temperature.

Question 8.
Name two non-metals which are in gaseous state at room temperature.
Answer:
Hydrogen and oxygen are in gaseous state at room temperature.

Question 9.
Name the non-metal having electrical conductivity.
Answer:
Graphite has electrical conductivity.

Question 10.
Name two non-metals which are lustrous.
Answer:
Iodine and diamond are lustrous in nature.

Question 11.
Name two non-metals having high melting points.
Answer:
Carbon and boron melt at high temperature.

Question 12.
State two metals which can be cut easily with a knife.
Answer:
Sodium and potassium are soft metals and can be cut easily with a knife.

Question 13.
Which is the hardest natural substance?
Answer:
Diamond, which is a form of carbon is the hardest natural substance.

Question 14.
State the property of the metals for which they can be drawn into wires.
Answer:
The property of the metals due to which they can be drawn into wires is called ductility.

Question 15.
State the property of the metals due to which they can be beaten into thin sheets.
Answer:
The property of the metals due to which they can be beaten into thin sheets is called malleability.

Question 16.
Which of the following metals react with cold water? Sodium, iron, copper, potassium.
Answer:
Sodium and potassium metals react with cold water.

Question 17.
Which of the following metals do not react with cold water or hot water?
Answer:
Aluminium and iron do not react with cold water or hot water.

Question 18.
What are the constituents of stainless steel?
Answer:
Iron with carbon, chromium and nickel are the constituents of stainless steel.

Question 19.
State the term used to express the purity of gold.
Answer:
The purity of gold is expressed in carat.

Question 20.
Name two metals having low melting points and boiling points.
Answer:
Sodium and potassium having low melting points and boiling points.

Question 21.
Name a non-metal which is in liquid state at room temperature.
Answer:
Bromine is in liquid state at room temperature.

Question 22.
State the atomic number and electronic configuration of sodium.
Answer:
Atomic number of sodium: 11.
Electronic configuration of sodium (Na): 2, 8, 1.

Question 23.
State the atomic number and electronic configuration of aluminium.
Answer:
Atomic number of aluminium: 13.
Electronic configuration of aluminium (Al): 2, 8, 3.

Question 24.
Give two example of metalloids.
Answer:
Metalloids: Arsenic (As),
germanium (Ge), antimony (Sb).

Question 25.
State the atomic number and electronic configuration of nitrogen.
Answer:
Atomic number of nitrogen: 7.
Electronic configuration of nitrogen (N): 2, 5.

Answer the following questions:

Question 1.
A metal can be drawn into a wire. Explain why.
Answer:

The property due to which a substance can be draw into a thin wire is called ductility.
Metals are ductile. Thus, a metal can be draw into a wire.

Question 2.
A metal can be hammered into a i thin sheet. Explain why.
Answer:

The property due to which a substance can be hammered (or rolled) into a thin sheet without cracking is called malleability.
Metals are malleable. Thus, a metal can be hammered to form a thin sheet.

Question 3.
State the properties of metals.
Answer:

Metals have a lustre.
Metals are malleable. They can be beaten into thin sheets.
Metals are ductile. They can be drawn into wires.
They are good conductors of heat and electricity.
At ordinary temperature, metals are generally solid. (Exception: Mercury is liquid.)
Metals usually have high density.

Question 4.
State the properties of non-metals.
Answer:

Non-metals lack lustre.
As non-metals are brittle, they are not malleable.
They are not ductile.
Non-metals are poor conductors of heat and electricity.
At ordinary temperature, non-metals are in the solid or gaseous state. (Exception: Bromine is liquid.)
Non-metals have low density in the solid state.

Question 5.
How are metal ions formed? Give two examples.
Answer:
Metals have a tendency to lose their valence electrons to form positively charged ions, called cations.
Examples:

Question 6.
Classify the following elements into metals and non-metals :
Silicon, gold, silver, sulphur, carbon, aluminium, copper and phosphorus.
Answer:
Metals: Gold, silver, aluminium and copper.
Non-metals: Silicon, sulphur, carbon and phosphorus.

Question 7.
How are metal oxides formed? Explain with an example.
Answer:
Metals combine with oxygen in the ’ air to form their oxides.
Metal + Oxygen → Metal oxide
[Note: Reaction/explanation given in the screen are for better understanding of students. The same are not given in the textbook.]
When magnesium burns in air, it combines with oxygen to form magnesium oxide.
2Mg + O₂ → 2MgO
Magnesium Oxygen Magnesium oxide

Question 8.
How will you show that metal oxides are basic in nature?
Answer:
1. Take magnesium oxide in a test S tube. Add water in the test-tube. Shake the test-tube. Test the solution with red and blue litmus paper. Blue litmus paper remains as it is while red litmus paper turns blue. This shows that metal oxides are basic in nature.

2. Metal oxides react with an acid to form salt and water. Therefore, metal oxides are basic in nature.
Metal oxide + Acid → + Water

Question 9.
How do metals react with acid? Explain with an example.
Answer:
The metals react with dilute acids to form metal salts. Metals liberate hydrogen gas from dilute acids.
Metal + Dilute acid → Metal salt + Hydrogen gas.
Magnesium reacts with dilute HCl to form magnesium chloride and hydrogen gas.

Question 10.
How do metals react with water? Explain with an example.
Answer:
Most metals do not react with cold water. But some metals like sodium and potassium react with cold water to form their hydroxides and hydrogen gas.
Sodium reacts with water to form sodium hydroxide.

Question 11.
How do non-metals react with oxygen? Explain with an example.
Answer:
Non-metals combine with oxyen to form their oxides.
Non-metal + Oxygen → Non-metal oxide
When carbon burns in air, it combines with oxygen to form carbon dioxide.

Question 12.
How will you show that non- metal oxides are acidic in nature?
Answer:
1. Take non-metal oxide in a test tube. Add water in the test tube. Test the solution with blue and red litmus paper. Red litmus paper remains as it is while blue litmus paper turns red. This shows that non¬metal oxides are acidic in nature.

2. The oxides of non-metals are acidic in nature. They react with bases to form soluble salt and water. Therefore, non-metal oxides are acidic in nature.
C + O₂ → CO₂
CO₂ + 2NaOH → Na2CO₃ + H₂O

Question 13.
How are non-metal ions formed? Give two examples.
Answer: Non-metals have a tendency to accept electrons in their valence shell to form negatively charged ions called anions.
Examples:

Question 14.
What is meant by noble metals? Give two examples.
Answer:
Some metals like gold, silver, platinum, paladium and rhodium are found in nature in the form of elements. They are not affected by air, water, acids and heat etc. Hence, they are called noble metals.

Give scientific reasons:

Question 1.
Ornaments are generally not made from 24-carat gold.
Answer:

24-carat gold is considered as gold of 100% purity.
24-carat pure gold is very soft. 100% pure gold breaks due to pressure or gets bent easily. Therefore, ornaments are generally not made from 24-carat gold.

Question 2.
Ships are painted at frequent intervals.
Answer:
1. The metal sheets of ships are made from iron.
2. Due to salty seawater, the metal sheets of ships get rusted and corroded. Paints contain metals like zinc or magnesium. This prevents the metal surface of the ship coming into direct contact with salty seawater. Therefore, ships are painted at frequent intervals.

Question 3.
Gold and platinum are called noble elements.
Answer:

The metals such as gold and platinum are found in nature in the form of elements.
They are not affected by water, air, acids, heat and also do not take part in chemical reactions. Hence, they are called noble metals.

Explain the following reactions with the help of balanced equations:

Question 1.
Magnesium combines with oxygen.
Answer:
Magnesium combines with oxygen to form magnesium oxide.

Question 2.
Magnesium oxide reacts with dilute HCl.
Answer:
When magnesium oxide reacts with dilute HCl, magnesium chloride (salt) and water are formed.

Question 3.
Magnesium reacts with dilute HCl.
Answer:
When magnesium reacts with dil.
hydrochloric acid, magnesium chloride is formed and hydrogen gas is evolved.

Question 4.
Sodium reacts with water.
Answer:
When sodium reacts with water, sodium hydroxide and hydrogen gas are formed.

Question 5.
Carbon burns in air.
Answer:
When carbon burns in air, carbon dioxide is formed.

Question 6.
Carbon dioxide reacts with sodium hydroxide.
Answer:
When carbon dioxide reacts with sodium hydroxide, soluble salt sodium ; carbonate and water are formed.

Question 7.
Carbon dioxide reacts with water.
Answer:
When carbon dioxide reacts with water, carbonic acid is formed.

Question 8.
Sulphur dioxide reacts with water.
Answer:
When sulphur dioxide reacts with water, sulphurous acid is formed.

Question 9.
Sulphur trioxide reacts with water.
Answer:
When sulphur trioxide reacts with water, sulphuric acid is formed.

Write short notes:

Question 1.
The noble metals.
Answer:
Some metals like gold, silver, platinum, paladium and rhodium are found in nature in the form of elements. They are not affected by air, water, acids and heat etc. Hence, they are called noble metals.

Uses of Nobel Metals:

Gold, silver and platinum are used to prepare ornaments.
Silver is used in medicines. (It has antibacterial property).
Gold and silver are also used to make metals and few electronic devices.
Platinum, palladium metals are used as catalyst. .

Question 2.
The purity of gold.
Answer:
1. The purity of gold is measured in carats.
2. Twenty-four carat gold is considered as gold of 100% purity.
3. 24-carat pure gold is very soft. 100% pure gold bends easily or breaks due to pressure. Therefore, copper or silver is added to gold in the necessary proportion (while making ornaments).
4. Generally, 22-carat gold is used in making ornaments.

Percentage of gold	Carat
100%	24
91.66%	22
75%	18
58.33%	14
50%	12
41.66%	10

Question 3.
Corrosion.
Answer:
Corrosion: Gases in the air react with metals in presence of moisture to form metal compounds on its surface, this destroys the metal gradually and is called corrosion.

By applying a layer of paint, oil, grease or varnish on the surface of a metal to prevent corrosion. Also plating with noncorroding metal is done. Iron is coated with thin layer of zinc. Due to these processes, the contact of a metal surface with air is lost and corrosion is prevented.

A reddish coloured deposit (rust) is formed on iron by reaction with oxygen gas.
A greenish coloured deposit (copper carbonate) is formed on copper by reaction with carbon dioxide.
A blackish coloured deposit is formed (silver sulphide) on silver.
Corrosion causes damages to car bodies, bridges, iron railings, ships specially those of iron, silver articles and copper vessels.

Question 4.
Alloys.
Answer:

A homogeneous mixture of two or more metals or of metals and non-metals is called an alloy.
They contain metals in specific proportions.
The physical properties of an alloy are different from those of its constituents, but chemical properties remain the same.
Copper and tin are used to make an alloy called bronze. It is hard and corrosion resistant.
When iron and carbon are mixed, an alloy steel is formed. It is a stronger material.
The alloy, stainless steel is made from iron, carbon, nickel and chromium. It is more durable, clean and does not rust.

Distinguish between the following:

Question 1.
Metals and Non-metals
Answer:

Metals	Non-metals
1. Metals have lustre.	1. Non-metals do not have lustre.
2. Metals are malleable.	2. Non-metals are not malleable.
3. Metals are ductile.	3. Non-metals are not ductile.
4. Metals are good conductors of heat and electricity.	4. Non-metals are poor conductors of heat and electricity.
5. At room temperature, metals are in the solid state. (Exception : Mercury is liquid.)	5. At room temperature, non-metals are in the solid, or gaseous state. (Exception Bromine. It is in liquid state.)
6. Generally, metals have high densities.	6. Generally, non-metals have lower densities.

8th Std Science Questions And Answers:

Disaster Management Class 8 Science Chapter 9 Questions And Answers Maharashtra Board

February 6, 2025February 5, 2025 by Bhagya

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 9 Disaster Management Notes, Textbook Exercise Important Questions and Answers.

Std 8 Science Chapter 9 Disaster Management Question Answer Maharashtra Board

Class 8 Science Chapter 9 Disaster Management Question Answer Maharashtra Board

1. Answer the following in your own words.

Question a.
Explain the relation between continuous rains and landslide. Give reasons.
Answer:
Before the actual landslide, many changes occur in the surrounding hilly ground. The hard rocks develop cracks and crevices. These are natural changes but due to man-made activities, the cracks are widened due to erosion. These cracks make the big rocks to break into smaller stones. The cracks widen further due to excessive rainfall. These rocks further get eroded and they fall down along with soil from the slopes. The entire process is speeded up due to rainwater.

Question b.
Prepare a chart showing ‘Dos’ and ‘don’ts’ at the time of earthquake.
Answer:
At the time of earthquake

Dos	Don’ts
1. Go in the open grounds.	1. Don’t wait in the multi-storeyed buildings. Do not use lifts. Use stairs to descend.
2. Keep the electrical appliances and cooking gas closed.	2. Do not stand near buildings, trees or electric wires and poles.
3. Use battery or torch.	3. Do not light candles, lantern or match- sticks.
4. Stand silently at one place. Do not panic or get scared.	4. Do not sit in uncomfortable posture for a long time.
5. Take protection under some hard covering, especially to protect the head and face. Cover the face.
6. If, in vehicle, find a safe place and stop the vehicle, sit in the vehicle than coming out in open.

Question c.
What are the specifications of an earthquake-proof building?
Answer:
The earthquake-proof building is such that even if the earthquake is caused, it should not cause damage to the buildings due to these earth movements. There are some codes of conduct while constructing such buildings. Advanced technology is used for earthquake resistant construction. The foundation of earthquake-proof building is separated from lower land. The walls are of less weight or they are wooden. The house constructed with special light materials are preferred in earthquake-prone regions.

Question d.
Explain the effects of landslide.
Answer:
1. Mostly rivers originate in the hills and mountains. When there is landslide, the rivers naturally get flooded.
2. The paths of the riverine water changes due to landslide.
3. Waterfalls are displaced from their original positions.
4. New and artificial water reservoirs are created.
5. The falling debris, soil and rocks make the trees at the base of hillside uprooted. All the plant life is lost.
6. The constructions done by the villagers on the slope can be totally damaged due to landslide. There is large scale damage to property and life. In few cases like Malin the entire village was buried due to landslide and accompanied rainfall.
7. Transportation is affected as the roads and railway tracks are blocked due to debris.

Question e.
Is there any relation between dam and earthquake? Explain.
Answer:
There is abundant water stored in the dams. This water column puts additional weight on the ground. Initially there may not be any weight, but later due to construction of dam, suddenly the pressure of this weight is so high that this ground experiences the tension. If such area is already earthquake-prone, then there can be chances of earthquake. According to theory of plate tectonics, there are continuous movements in the earth’s surface. If over such fragile plates, the dams are constructed then the chances of earthquake are enhanced.

2. Give Scientific reasons.

Question a.
It is safer to find shelter under things like a bed, table at the time of earthquake.
Answer:
When earthquake takes place, due to the vibrations in the earth’s surface, there is possibility of the roof and walls of the house to fall. This collapse can cause severe head injury which can be fatal. Thus, one must take shelter below the hard-supporting structures such as bed or table. This precaution can save one’s life.

Question b.
In monsoon, don’t take shelter near hillside.
Answer:
The excessive rainfall can cause landslides. The soil and rocks from the hillside can be pushed down along with the flow of rainwater. This debris slides to the lower heights from the hills. This explains us that taking shelter near the base of the hillside can be disastrous as one can be buried in the debris due to sudden landslide. Therefore, in monsoon, one should not take shelter near hillside.

Question c.
Don’t use lifts at the time of earthquake.
Answer:
Lifts or elevators run on electricity. The electricity supply can be hindered due to earthquake. There may be chances of fire due to short circuit. We may get trapped in the elevator at such times. The building may also collapse due to earthquake. It is always better to use stairs at the time of such calamities, so that one can safely come out of the building. Therefore, it is said that lifts should not be used at the time of earthquakes.

Question d.
The foundation of earthquake- proof building is separated from lower land.
Answer:
The surface of the earth trembles at the time of earthquake. These tremors cause seismic waves which are responsible for the movements of the earth’s surface. The ground thus shakes or it goes up-down. These shocks and waves formed in the interior of the earth spread on the surface in all directions. This causes collapse of the building and other structures on the land.
To prevent such disasters the foundation of earth-quake proof building is separated from lower land.

3. If a crowd gathers at the place of earthquake, what would be the difficulties in relief work?

Question a.
If a crowd gathers at the place of earthquake, what would be the difficulties in relief work?
Answer:
If people flock in crowd, the rescue work will not be possible. The ambulances and the fire engines will not reach the spot where the help is needed. The personnel from disaster management cells cannot thus act in time. It will be difficult to manage the situation and thus such crowding should never be done.

4. Make a list of the institutes and organizations who provide help for disaster managment. Collect more information about their work.

Question a.
Make a list of the institutes and organizations who provide help for disaster management. Collect more information about their work.
Answer:
International government organisations working for disaster management are:
a. The United Nations and its organisations:
1. The Food and Agricultural Organisation of the UN (FAO): It gives early warning of impending food crises, and keep track of global food supply problems.
2. The United Nations Development Programme (UNDP): It helps disaster-prone countries with disaster mitigation, prevention and preparedness measures.
3. The World Food Programme (WFP): It is the main supplier of relief food aid.
4. The World Health Organisation (WHO): It gives global public health leadership by setting standards, monitoring health trends, and providing direction on emergency health issues. WHO’s role is to reduce avoidable loss of life and the burden of disease and disability.

b. The International Committee of the Red Cross ( ICRC): It gives physical rehabilitation to people injured by explosive weapons or other types of incident.

c. The International Federation of Red Cross and Red Crescent Societies ( IFRC): It coordinates and gives international help to victims of natural and technological disasters, to refugees and in health emergencies.

International non-governmental agencies working for disaster management are:
a. International Rescue Committee (IRC): It provides lifesaving care and life-changing help to refugees forced to flee from war or disaster.

b. IMA World Health: It, in collaboration with USAID, the World Bank and many other organisations, builds sustainable health care systems.

c. CARE: It is an organisation fighting global poverty. It works for women and puts efforts to improve their basic education, prevent the spread of HIV by providing awareness among them, give them increase access to clean water and sanitation, expand economic opportunity for them. It provides emergency aid to survivors of war and natural disasters, and helps people rebuild their lives.

Indian organisations and institutes working for disaster management are:
a. National Disaster Response Force (NDRF): The multi-disciplinary, multi-skilled, high-tech force of the NDMA are capable of dealing with all types of natural and man-made disasters.

b. National Disaster Management Authority (NDMA): It lay down the policies, plans and guidelines for Disaster Management to ensure timely and effective response to disasters.

c. National Institute of Disaster Management (NIDM): It has been given the responsibilities for human resource development, capacity building, training, research, documentation and policy advocacy in the field of disaster management.

5. Make a survey of your school according to the plan of disaster management an write the pointwise information.

Question a.
Make a survey of your school according to the plan of disaster managment an write the pointwise information.
Answer:

This an activity based questions. Kindly do it yourself. But make sure to involve the following points in your survey:

Primary information of the school: It should include information such as name and address of the school and Head Master, total number of school staff and name and phone numbers of school management members.
School disaster management committee: Get the information of the members involved in disaster management committee.
Detailed information about school building: Note the number of rooms, classroom, age of the building, types of roofs under this point.
Information about school ground: It should include information like distance of ground from the main road, types of play grounds.
Daily routine of the school: It should include information like working time of the school, lunch break time for the school.
Possible hazards in the school: It should information such as record of past disaster happened in school, current planning for overcoming disasters.
Disaster management map of the school: It should have information regarding all the buildings of the school, entrances and exit gates, place of probable danger, safer place at the time of disaster.

6. Are there any possible places of landslide in your area? Collect information from experts.

Question a.
Are there any possible places of landslide in your area? Collect information from experts.
Answer:
This is an activity based question. kindly do it yourself.

7. With the help of the following pictures, explain your role in disaster management.

Question a.
With the help of following pictures, explain your role in the disaster management.
Answer:

The picture given is not very clear. It does not indicate the condition of disaster. Therefore, there are two alternatives for this answer.
Option 1 : The boy holds a paper on which is written, ‘I am at risk’! The boy is shocked to read this. Someone has given message to him. He must search that person and help him or her. He should therefore take help from some elder or from police force in such matter.

Option 2 : The boy shown in the picture is in danger. So, he is typing in his I – pad, “I am at Risk”. After receiving this message, someone will help him. It depends upon, to whom is he sending this message. If he sends this message to us, we can immediately try to help him. His message “I am at Risk”, shows that he is in danger and has to be saved.
It is not clear about which disaster is shown in the picture.

Project:

Question 1.
Make a collection of news, photos. and cuttings about landslides and rift collapse.

Question 2.
With the help of Internet, collect information about the latest gadgets and technology to forecast earthquake.

Question 3.
Collect information about NDRF, RPF, CRPF, NCC from Internet.

Question 4.
Discuss- Need of CCTV.

Class 8 Science Chapter 9 Disaster Management Important Questions and Answers

Rewrite the sentences after filling the blanks:

Question 1.
Earthquakes cause ……………. waves leading to movements of the earth’s surface.
Answer:
Earthquakes cause seismic waves leading to movements of the earth’s surface.

Question 2.
The central point of earthquake is the point above the ……………. on the earth’s surface.
Answer:
The central point of earthquake is the point above the epicentre on the earth’s surface.

Question 3.
The accentuation of earthquake is measured in …………… .
Answer:
The accentuation of earthquake is measured in ‘Richter Scale’.

Question 4.
If there is earthquake at the bottom of ocean, it may create ……………… waves.
Answer:
If there is earthquake at the bottom of ocean, it may create tsunami waves.

Question 5.
…………….. is the best device to put off small fires.
Answer:
Stirrup pump is the best device to put off small fires.

Question 6.
………………. of waterfalls occurs due to landslides.
Answer:
Displacement of waterfalls occurs due to landslides.

State whether the following statements are True or False:

Question 1.
Every year nearly 2,400 to 4,000 earthquakes occur on the earth.
Answer:
False. (Every year nearly 12,400 to 14,000 earthquakes occur on the earth.)

Question 2.
Potassium, sodium and calcium are the metals that react with water at high room temperature.
Answer:
False. (Potassium, sodium and calcium are the metals that react with water at normal room temperature.)

Question 3.
A fire caused due to electrical components is extinguished by fire extinguishers like carbon dioxide are used.
Answer:
True.

Question 4.
Indiscriminate cutting of the trees results in improvement of soil quality.
Answer:
False. (Indiscriminate cutting of the trees results in soil erosion.)

Question 5.
Landslide results in loss of plant life.
Answer:
True.

Match the column:

Question 1.

Column ‘A’	Column ‘B’
1. Class A fire	a. Electrical components
2. Class B fire	b. Gaseous substances
3. Class C fire	c. Chemical substances
4. Class D fire	d. Liquid substances
5. Class E fire	e. Solid substances

Answer:

Column ‘A’	Column ‘B’
1. Class A fire	e. Solid substances
2. Class B fire	d. Liquid substances
3. Class C fire	b. Gaseous substances
4. Class D fire	c. Chemical substances
5. Class E fire	a. Electrical components

Question 2.

Column ‘A’	Column ‘B’
1. Earthquake	a. Formation of artificial water reservoir
2. Tsunami	b. Wildlife lost
3. Forest fire	c. Loss of coastal regions
4. Landslide	d. Change in the level of groundwater-table

Answer:

Column ‘A’	Column ‘B’
1. Earthquake	d. Change in the level of groundwater-table
2. Tsunami	c. Loss of coastal regions
3. Forest fire	b. Wildlife lost
4. Landslide	a. Formation of artificial water reservoir

Name the following:

Question 1.
Modern equipment to get prior intimation about earthquake:
Answer:

Laser ranging
Very long baseline
Geiger counter
Creep meter
Strain meter
Tide gauge
Tilt meter
Volumetric strain gauge.

Question 2.
Some code of conduct made by Indian Standard Institute for construction of buildings:
Answer:

IS 456
IS 1893
IS 13920

Question 3.
The subcommittees of School Disaster Management.
Answer:

Fire extinguisher
Awareness
Instructions
Traffic management
Safety
Communication committee.

Answer the following questions in one sentence:

Question 1.
Which is the instrument or machine that records the intensity of earthquake?
Answer:
The machine/Instrument which records the earthquakes is called ‘Seismograph’ or ‘Seismometer’.

Question 2.
Which is the most common and effective solution for extinguishing fire ?
Answer:
Spraying water is the most common and effective solution for extinguishing fire.:

Question 3.
Which type of fires can be extinguished by the method of suppressing?
Answer:
To extinguish the fires caused due to electricity or oil, the method of suppressing the fire can be used.

Question 4.
Which metals react with water at normal room temperature?
Answer:
Combustible metals like potassium, sodium and calcium, react with water at normal room temperature.

Question 5.
Which metals react with water at higher temperatures?
Answer:
Magnesium, aluminum and zinc react with water at high temperatures.

Question 6.
Which institutes have launched a program to forecast the landslides and its effects?
Answer:
The Government of India in collaboration with Indian Mountaineering Institute and International Centre for Integrated Mountain Development has launched a program to forecast the landslides and its effects.

Give scientific reasons:

Question 1.
The electric mains are shut off immediately after the earthquake.
Answer:
There is increased possibility of short circuit after the earthquake. This may result in fire. The earthquake has already – brought the disaster. To prevent further destruction, the electric mains are shut off immediately after the earthquake.

Write short notes:

Question 1.
Types of fire:
Answer:
There are five types of fire. This division is based on two criteria, viz.
(i) Which substance is being burnt, (ii) What is the method of extinguishing it.
1. Class A Fire: Commonly inflammable solid things such as wood, clothes, coal, papers can be burnt by this type of fire. This fire is extinguished by spraying water over it. This is also called cooling out. Water is effectively used to put off class A fire.

2. Class B Fire: Flammable liquid substances such as petrol, oil, varnish, solvents, cooking oil, paints, etc. catch fire and it is called class B fire. Since these substances are lighter than water, they can be extinguished only by foaming fire extinguishers.

3. Class C Fire: The fire caused due to gaseous substances is called class C fire. Domestic gas (L.P.G.) and acetylene can cause such kind of fire.

4. Class D Fire: Combustible metals catch class D fire. Metals such as potassium, sodium and calcium, can react with water at normal room temperature whereas magnesium, aluminium and zinc react with water at high temperature. When both these groups combine with water, it causes explosion.

5. Class E Fire: When electric components are subjected to fire, they form class C fire. Such fires can be caused by short circuit or due to problems in electric fittings. Such fire is extinguished with the help of carbon dioxide and non-conductive fire extinguishers.

Question 2.
Disaster relief – planning.
Answer:
Anyone can face disaster at any time. The only way to tackle with such disasters is to keep preparedness to deal with any calamity. Schools, colleges and various offices need to chalk out a detailed planning in case of possible disasters. With this purpose in mind, disaster relief planning is done.

E.g. In the disaster relief planning for school, primary information of the school, the structure of School Disaster Management Committee, detailed information about school building and information about school ground, daily routine of the school such as at what time the school starts and what time does it end, the possible hazards in the school, and disaster management map of the school is included.

Answer the following questions:

Question 1.
What are the different ways to extinguish fire? Write briefly about them.
Answer:
There are three main methods to extinguish the fire. These methods are used to stop the spread of fire and to avoid the financial and other losses.
1. Cooling out by use of water: Water is easily available and can be used for putting off fire instantly. Due to spraying of water, there is cooling effect produced which helps in reducing the loss by fire. Fire can be easily controlled by water.

2. Suppressing the fire by covering it: When there is a fire due to electricity or oil it has to be controlled by covering the fire by sand or soil. When the froth is spread on the fire, there is no contact between air and fire. This puts off the fire and stops the spread of fire caused due to oil.

3. Keep away Flammable Substances: Care is taken to keep away all flammable substances from the fire. Wooden articles and inflammable substances are kept in such as way the fire will not engulf it. Stirrup pumps are used to put off small fires by which the water is spread in all directions around the fire.

Question 2
What are the safety measures and precautions to stop the fire?
Answer:

Switching off the regulator of cooking gas cylinder when not in use. Put off the connections of all electrical appliances when not in use.
If there is fire, call others immediately for help. Take help of others by calling them. Also help others who are in need to save their lives from fire.
Get help from fire brigade by calling phone number 101.
Know details about working of the fire extinguishing apparatus.
Give first aid to the victim of fire. Seek immediate medical help,

Question 3.
What are the causes of landslide?
Answer:

Various types of natural disasters like earthquakes, tsunami, heavy rains, storms, floods can result into landslide.
The indiscriminate cutting down of the trees can result into soil erosion. Soil erosion in turn results into landslide.
The construction of roads, bridges, railway tracks, etc. on the mountain slopes result into lot of digging. Such activities make soil cover loose. From the slopes the soil and rocks then can slide easily. This results into landslides.

Draw a well labelled diagrams:

Question 1
Seismometer/Secismograph.
Answer:

Question 2.
Focal point and epicenter or earthquake.
Answer:

Open-Ended Questions:

Question 1.
Have you at any time faced with any disaster? What were your experiences during such condition? How did you get rescued?
Answer:
Students should write their own experiences about such incidents if any.

Question 2.
In Maharashtra where do the traffic jams occur due to landslides? Make a list of such places. Why does the landslide occur at those places only? Discuss in the classroom and suggest preventive measures.
Answer:
In Maharashtra, the landslides are very common in the hilly regions. The traffic is suspended often during rainy season when such calamity strikes. Malshej, Khandala, Kasara are some of the Ghats which are very prone to land-slide. On the tracks of Konkan railway, the landslides are very common during heavy downpour.

The regions where more landslides occur have many constructions and large scale deforestation. The traffic of Konkan railway comes to standstill after such landslide. Moreover, during heavy monsoon days, the speed of the running trains is kept very slow. The soil structure is also responsible for such landslides.

Preventive measures: There should be wire meshing done across the sides of the roads and railway tracks so that the collapsed rocks and other debris does not obstruct the traffic. Tree plantation should be carried out to prevent loosening of the soil and rock. It will also help in preventing the soil erosion.

8th Std Science Questions And Answers:

Inside the Atom Class 8 Science Chapter 5 Questions And Answers Maharashtra Board

February 6, 2025February 5, 2025 by Bhagya

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 5 Inside the Atom Notes, Textbook Exercise Important Questions and Answers.

Std 8 Science Chapter 5 Inside the Atom Question Answer Maharashtra Board

Class 8 Science Chapter 5 Inside the Atom Question Answer Maharashtra Board

1. Answer the following.

Question a.
What is the difference in the atomic models of Thomson and Rutherford?
Answer:

Thomson’s atomic model	Rutherford’s atomic model
1. According to Thomson’s atomic model, the negatively charged electrons are embedded in a gel of positive charge.	1. According to Rutherford’s atomic model the negatively charged electrons revolve around the nucleus.
2. Atom is homogenous sphere of positive charge.	2. The positive charge is in the nucleus of the atom.

Question b.
What is meant by valency of an element? What is the relationship between the number of valence electron and valency?
Answer:
Valency: The capacity of an ; element to combine with another element is known as valency.
Valence electrons: The electrons in the outermost shell of an atom of an element are called valence electrons.
Helium and neon, atoms of both these gaseous element do not combine with any other atom. These elements are chemically inert, i.e. their valency is zero.

Helium atom contains two electrons, indicates that the outermost shell of helium has an electron duplet. The valence shell of neon is completely filled, i.e. neon has an electron octet. Similarly argon contains eight electrons in the valence shell, i.e. argon has an electron octet. It is confirmed that the valency is zero when electron octet (or duplet) is complete.

Atoms of all the elements except inert gases have tendency to combine with other atoms, i.e. they have a non zero valency. The molecules formed by combination with hydrogen (E.g. H₂, HCl) that valency of hydrogen is one. The electronic configuration of hydrogen shows that there is one electron less than the complete duplet state. This number ‘one’ matches with the valency of hydrogen which is also one.

It means that there is relationship between the valency of an element and the number of electrons in its valence shell.

Question c.
What is meant by atomic mass i number? Explain how the atomic number and mass number of carbon are 6 and 12 respectively.
Answer:
The total number of protons and neutrons in the nucleus of the atom is called the atomic mass number. The atomic number, i.e. the proton number of carbon is 6 and the mass number is total number of protons and neutrons in the carbon, i.e. 6 protons + 6 neutrons = 12. Therefore, the atomic number and mass number of carbon are 6 and 12 respectively.

Question d.
What is meant by subatomic particle? Give brief information of three subatomic particles with reference to electrical charge, mass and location.
Answer:
A particle which is a constituent of an atom hence smaller than the atom is called subatomic particle.
An atom is formed from the nucleus and the extranuclear part. These contain three types of subatomic particles.
The nucleus contains two types of subatomic particles together called nucleons. Protons and neutrons are the two types of nucleons or subatomic particles and electrons are subatomic particles in the extra nuclear part.

1. Proton (p): Proton is a positively charged subatomic particle in the atomic nucleus. The positive charge on the nucleus is due to the proton in it. A proton is represented by the symbol ‘p’. Each proton carries a positive charge of +1e. (1e = 1.6 × 10^-19 coulomb). When total positive charge on the nucleus is expressed in the unit ‘e’, its magnitude is equal to the number of proton in the nucleus.
The mass of one proton is approximately lu (1 Dalton).
(1u = 1.66 × 10^-27g) (The mass of one hydrogen atom is also approximately lu.)

2. Neutron (n): Neutron is an electrically neutral subatomic particle and is denoted by the symbol ‘n’. The number of neutron in the nucleus is denoted by the symbol ‘N’ Atomic nuclei of all the elements except hydrogen with atomic mass lu, contain neutrons. The mass of a neutron is approximately lu, which is almost equal to that of a proton.

3. Electron (e^–): Electron is a negatively charged subatomic particle and is denoted by the symbol ‘e-’. Each electron carries one unit of negative charge (-1e). Mass of an electron is 1800 times less than that of a hydrogen atom. Therefore the mass of an electron can be treated as negligible. Electron in the extranuclear part revolve in the discrete orbits around the nucleus. The energy of an electron is determined by the shell in which it is present.

2. Give scientific reasons:

Question a.
All the mass of an atom is concentrated in the nucleus.
Answer:

The nucleus of an atom contains protons and neutrons.
The electrons revolve around the nucleus.
The mass of an electron is negligible compared to that of a proton or a neutron.
Hence, the mass of an atom depends mainly on the number of protons and neutrons. Therefore, practically all the mass of an atom is concentrated in the nucleus.

Question b.
Atom is electrically neutral.
Answer:

An atom is made of two parts, viz. the nucleus and the extranuclear part.
The nucleus is positively charged. The positive charge on the nucleus is due to protons.
The extranuclear part of an atom is made of negatively charged electrons.
In an atom, the number of protons is equal to the number of extranuclear electrons.
The magnitude of the positive charge on the nucleus equals the magnitude of the negative charge on the electrons. As the opposite charges are balanced, the atom is electrically neutral.

Question c.
Atomic mass number is a whole number.
Answer:

The total number of protons and neutrons in the nucleus of the atom is called the atomic mass number (A).
As protons and neutrons are whole numbers, the atomic mass number is also a whole number.

Question d.
Atoms are stable though negatively charged electron are revolving within it.
Answer:

The entire mass of the atom is concentrated in the nucleus and the positively charged nucleus at centre of an atom.
The negatively charged electrons revolve around the nucleus.
The total negative charge on all the electron is equal to positive charge on the nucleus. As the opposite charges are balanced, the atom is stable.

3. Define the following terms.

Question a.
Atom:
Answer:
An atom is the smallest particle of an element which retains its chemical identity in all physical and chemical changes.

Question b.
Isotope
Answer:
Atoms of the same element having the same atomic number, but different atomic mass numbers are called isotopes.

Question c.
Atomic number
Answer:
The number of electrons or protons in an atom is called the atomic number. It is denoted by Z.

Question d.
Atomic mass number
Answer:
The total number of protons and neutrons in the nucleus of the atom is called the atomic mass number. It is denoted by A.

Question e.
Moderator in nuclear reactor
Answer:
The substance which reduces the speed of fast-moving neutrons produced in a fission is called a moderator.

4. Draw a neal labelled diagram.

Question a.
Explain Rutherford’s scattering experiment.
Answer:

Alpha particles emitted by radioactive element bear a positive charge. Rutherford bombarded alpha particles through a very thin gold foil. He observed the path of α – particles by means of a fluorescent screen around the gold foil. It was expected that

Most of the alpha particles passed through the gold foil without any deviation.
Some alpha particles were deflected from their path through small angles.
A few alpha particles were scattered at large angles.
A still smaller number of same sign particles get deflected through a larger angle and one a-particle out of 20000 bounced back in the direction opposite to the original path.

Question b.
Thomson’s atomic model.
Answer:
Thomson’s plum pudding model of atom:

According to Thomson’s model the positive charge is distributed throughout the atom and the negatively charged electron: are embedded in a gel of positive charge (a plum pudding model).
The distributed positive charge is balanced by the negative charge on the electrons. Therefore the atom becomes electrically neutral.

Question c.
Diagrammatic sketch of electronic configuration of magnesium (Atomic number 12).
Answer:

Question d.
Diagrammatic sketch of electronic configuration of argon (Atomic number 18).
Answer:

5. Fill in the blanks.

Question 1.
Electron, proton, neutron are the types of ………… in an atom.
Answer:
Electron, proton, neutron are the types of subatomic particles in an atom.

Question 2.
An electron carries a ……………. charge.
Answer:
An electron carries a negative charge.

Question 3.
The electron shell ………….. is nearest to the nucleus.
Answer:
The electron shell K is nearest to the nucleus.

Question 4.
The electronic configuration of magnesium is 2, 8, 2. From this it is understood that the valence shell of Magnesium is …………….. .
Answer:
The electronic configuration of magnesium is 2, 8, 2. From this it is understood that the valence shell of Magnesium is M.

Question 5.
The valency of hydrogen is one as per the molecular formula H₂O. Therefore valency of ‘Fe’ turns out to be ………….. as per the formula Fe₂O₃.
Answer:
The valency of hydrogen is ‘one’ as per the molecular formula H₂O. Therefore valency of ‘Fe’ turns out to be 3 as per the formula Fe₂O₃.

6. Match the pairs.

Question 1.

Column I	Column II
1. Proton	a. Negatively charged
2. Electron	b. Neutral
3. Neutron	c. Positively charged

Answer:

Column I	Column II
1. Proton	c. Positively charged
2. Electron	a. Negatively charged
3. Neutron	b. Neutral

7. Deduce from the datum provided.

Question 1.

Answer:
1. There are 12 neutrons in the sodium $\left({ }_{11}^{23} \mathrm{Na}\right)$.
(N = A – Z) 23 – 11 = 12
2. Atomic mass number of ${ }_{6}^{14} \mathrm{C}$ is 14.
3. There are 17 protons in chlorine $\left({ }_{37}^{17} \mathrm{Cl}\right)$

Project:

Explain the atomic models using the material such as old C.D., balloon, thread, marbles, etc.

Class 8 Science Chapter 5 Inside the Atom Additional Important Questions and Answers

Rewrite the sentences after filling the blanks:

Question 1.
An atom is electrically ……………. .
Answer:
An atom is electrically neutral.

Question 2.
Except hydrogen, the nuclei of all atoms contain ………….. .
Answer:
Except hydrogen, the nuclei of all atoms contain neutrons.

Question 3.
${ }_{6}^{12} \mathrm{C}$, …………… and …………. are isotopes of carbon.
Answer:
${ }_{6}^{12} \mathrm{C}$, ${ }_{6}^{13} \mathrm{C}$ and ${ }_{6}^{14} \mathrm{C}$ are isotopes of carbon.

Question 4.
An atom has 11 protons and …………. neutrons and hence its atomic mass number is 23.
Answer:
An atom has 11 protons and 12 neutrons and hence its atomic mass number is 23.

Question 5.
The element ………….. has two electrons in the K shell, but it is a noble gas.
Answer:
The element helium has two electrons in the K shell, but it is a noble gas.

Question 6.
Isotopes of the element have the same ……….. properties.
Answer:
Isotopes of the element have the same chemical properties.

Question 7.
Electrons must absorb …………….. to transit between orbits.
Answer:
Electrons must absorb energy to transit between orbits.

Question 8.
……….. discovered the electron.
Answer:
J. J. Thomson discovered the electron.

Question 9.
∝ – particles have ………….. charge.
Answer:
∝ – particles have positive charge.

Question 10.
Electrons revolve around the …………….. in certain discrete orbits.
Answer:
Electrons revolve around the nucleus in certain discrete orbits.

Question 11.
The shell-wise distribution of electrons is called the ………………… .
Answer:
The shell-wise distribution of electrons is called the electronic configuration.

Question 12.
Democritus termed the smallest particles of matter as …………… .
Answer:
Democritus termed the smallest particles of matter as atoms.

Question 13.
………………. discovered neutron.
Answer:
James Chadwick discovered neutron.

Question 14.
Electrons revolve around the nucleus in paths called ………….. .
Answer:
Electrons revolve around the nucleus in paths called orbits.

Question 15.
The second shell has the capacity of ……………… .
Answer:
The second shell has the capacity of 8 electrons.

Question 16.
Electrons in the ………….. shell have minimum energy.
Answer:
Electrons in the K or first shell have minimum energy.

Question 17.
Electrons in an atom occupy shells in increasing order of …………… .
Answer:
Electrons in an atom occupy shells in increasing order of energy.

Question 18.
Atomic masses are measured in a unit called …………… .
Answer:
Atomic masses are measured in a unit called dalton.

Question 19.
According to the atomic model of …………….., electrons are embedded in a gel of positive charge.
Answer:
According to the atomic model of Thomson, electrons are embedded in a gel of positive charge.

Question 20.
All atoms, except ………….. contain neutrons in their nuclei.
Answer:
All atoms, except normal hydrogen contain neutrons in their nuclei.

Question 21.
The maximum capacity of the M shell is ………………… electrons.
Answer:
The maximum capacity of the M shell is 18 electrons.

Question 22.
The atom of the element ……………. has eight electrons in the outermost shell.
Answer:
The atom of the element neon has eight electrons in the outermost shell.

Rewrite the following statements selecting the correct options:

Question 1.
The symbol A is used to denote the …………. .
(a) atomic number
(b) atomic radius
(c) atomic mass number
(d) atomic mass
Answer:
(c) atomic mass number

Question 2.
The existence of isotopes is due to the presence of different number of …………….. .
(a) electrons
(b) protons
(c) neutrons
(d) positrons
Answer:
(c) neutrons

Question 3.
In the nucleus of a sodium atom (${ }_{11}^{23} \mathrm{Na}$), there are ……………… neutrons.
(a) 11
(b) 12
(c) 10
(d) 9
Answer:
(b) 12

Question 4.
Isotopes of an element have the same number of …………….. .
(a) neutrons
(b) nucleons
(c) electrons
(d) atoms
Answer:
(c) electrons

Question 5.
The great Indian philosopher ………….. proposed that matter is made up of invisible tiny particles.
(a) Aryabhatta
(b) Kanad
(c) Bhaskaracharya
(d) Chanakya
Answer:
(b) Kanad

Question 6.
The maximum capacity of the M shell is …………… electrons.
(a) 2
(b) 8
(c) 18
(d) 32
Answer:
(c) 18

Question 7.
The mass of the electron is …………….. times less than that of a hydrogen atom.
(a) 1800
(b) 8100
(c) 1550
(d) 1600
Answer:
(a) 1800

Question 8.
The L shell is the valence shell in …………. .
(a) hydrogen
(b) chlorine
(c) oxygen
(d) sodium
Answer:
(c) oxygen

Question 9.
The M shell is the valence shell in ……………….. .
(a) fluorine
(b) neon
(c) carbon
(d) chlorine
Answer:
(d) chlorine

Question 10.
The N shell is the valence shell in ………….. .
(a) fluorine
(b) chlorine
(c) bromine
(d) helium
Answer:
(c) bromine

Question 11.
The maximum capacity of the N shell is ……………. electrons.
(a) 2
(b) 32
(c) 18
(d) 8
Answer:
(b) 32

Question 12.
The maximum number of electrons that can be accommodated in the third orbit is ………… .
(a) 3
(b) 8
(c) 32
(d) 18
Answer:
(d) 18

Question 13.
Rutherford alpha-particle scattering experiment was responsible for the discovery of the ………………. .
(a) atomic nucleus
(b) proton
(c) electron
(d) atomic mass
Answer:
(d) atomic mass

Question 14.
Isotopes of element have …………….. .
(a) different atomic numbers and different atomic mass
(b) different atomic numbers but the same atomic mass number
(c) the same atomic number but different atomic mass numbers
(d) the same atomic number and the same atomic mass number
Answer:
(c) the same atomic number but different atomic mass numbers

Question 15.
The nucleus of an atom contains 19 protons and 21 neutrons. The atomic mass number of the element is ………….. .
(a) 19
(b) 21
(c) 40
(d) 39
Answer:
(c) 40

Question 16.
The nucleus of an atom contains 18 protons and 22 neutrons. The atomic number of the element is ……………… .
(a) 18
(b) 40
(c) 22
(d) 4
Answer:
(a) 18

Question 17.
When writing the symbol of its …………… and ………….. are written.
(a) atomic number, atomic mass number
(b) protons, electrons
(c) protons, neutrons
(d) atomic number, electrons
Answer:
(a) atomic number, atomic mass number

Question 18.
The particles in the atomic nucleus are …………….. .
(a) protons and electrons
(b) electrons
(c) electrons and neutrons
(d) protons and neutrons
Answer:
(d) protons and neutrons

State whether the following statements are True or False:

Question 1.
An atom as a whole is electrically neutral
Answer:
True.

Question 2.
The mass of an atom is distributed evenly within it.
Answer:
False. (The mass of atom is not distributed evenly, practically all the mass is concentrated in the nucleus.)

Question 3.
The electron has the same mass as that of the proton.
Answer:
False. (The mass of the electron is much less than that of the proton.)

Question 4.
The electron in the K shell has maximum energy.
Answer:
False. (The electrons in the K shell has minimum energy.)

Question 5.
Isotopes have same atomic number but different atomic mass number.
Answer:
True.

Question 6.
Matter is composed of molecules and molecules are made of atoms.
Answer:
True.

Question 7.
In India, total 22 nuclear reactors in eight places are functioning.
Answer:
True.

Question 8.
The number of electrons in a given orbit is given by the formula n
Answer:
False. (The number of electrons in a given orbit is given by the formula 2n2)

Question 9.
Atomic masses are measured in a unit called the dalton (u).
Answer:
True.

Question 10.
The chemical properties of isotopes are different.
Answer:
False. (The chemical properties of isotopes are the same.)

Question 11.
The maximum capacity of the N shell is 18 electrons.
Answer:
False. (The maximum capacity of the N shell is 32 electrons.)

Question 12.
Deuterium is an isotope of hydrogen.
Answer:
True.

Question 13.
Isotopes are used in the treatment of cancer.
Answer:
True.

Question 14.
Atoms of all elements, except normal hydrogen contain neutrons.
Answer:
True.

Question 15.
Electrons moving in different orbits possess the same amount of energy.
Answer:
False. (Electrons moving in different orbits possess different amounts of energy.

Question 16.
Rutherford discovered the neutron.
Answer:
False. (Chadwick discovered the neutron.)

Question 17.
The nth orbit contains at the most 2n² electrons.
Answer:
True.

Question 18.
Electrons have different energies according to their orbits.
Answer:
True.

Question 19.
The capacity of the second orbit is 18 electrons.
Answer:
False. (The capacity of the second orbit is 8 electrons.)

Question 20.
The radioactive isotope Sodium-24 is used in the medical treatment of cancer.
Answer:
False. (The radioactive isotope Sodium-24 is used for detection of cracks in the underground pipes.)

Question 21.
Uranium-235 is used in the production of electricity.
Answer:
True.

Consider the relation between I the items in the first pair and write the correlation for second pair:

Question 1.
K : 2 : M : …………. .
Answer:
18

Question 2.
Carbon : 2, 4 : : Fluorine : …………….. .
Answer:
2, 7

Question 3.
Nitrogen : Valency three : : Fluorine : …………….. .
Answer:
valency one

Question 4.
Atomic radius : pm : Atomic mass : ……………. .
Answer:
u

Question 5.
NaH : Valency of Na : 1 : : MgCl₂ : Valency of Mg …………… .
Answer:
2

Question 6.
$35 \mathrm{Cl}$ : number of neutrons 18 : : \({ }^{37} \mathrm{Cl}/latex] : …………….. .
Answer:
number of neutrons 20

Question 7.
Protons : Positive : : ……………. : Neutral.
Answer:
Neutrons.

Match the following:

Question 1.

Column I	Column II
1. Thomson	a. Well defined orbits
2. Rutherford	b. Neutron
3. Chadwick	c. Scattering experiment
4. Bohr	d. Electron

Answer:

Column I	Column II
1. Thomson	d. Electron
2. Rutherford	c. Scattering experiment
3. Chadwick	b. Neutron
4. Bohr	a. Well defined orbits

Question 2.

Column I	Column II
1. Atom	a. Treatment of goitre
2. Isotopes of iodine	b. Protons + Neutrons
3. Atomic mass number	c. Different number of neutrons
4. Isotopes	d. Electrically neutral

Answer:

Column I	Column II
1. Atom	d. Electrically neutral
2. Isotopes of iodine	a. Treatment of goitre
3. Atomic mass number	b. Protons + Neutrons
4. Isotopes	c. Different number of neutrons

Question 3.

Column I	Column II
1. Alpha particles	a. Inert element
2. Uranium-235	b. Negatively charged particles
3. Helium	c. Positively charged particles
4. Isotopes	d. Krypton – 92, Barium 141
	e. U-233, Th-232
	f. ¹²C, ¹³C, ¹⁴C

Answer:

Column I	Column II
1. Alpha particles	c. Positively charged particles
2. Uranium-235	d. Krypton – 92, Barium 141
3. Helium	a. Inert element
4. Isotopes	f. ¹²C, ¹³C, ¹⁴C

Distinguish between the following:

Question 1.
Proton and Neutron:
Answer:

Proton	Neutron
1. The proton is positively charged particle	1. The neutron does not have any charge.
2. In an atom, the number of protons is always equal to the number of electrons.	2. In general, in an atom, the number of neutrons is not equal to the number of electrons.

Question 2.
Neutron and Electron:
Answer:

Neutron	Electron
1. The neutron is an electrically neutral particle.	1. The electron is a negatively charged particle.
2. Neutrons are present in the nucleus of an atom.	2. Electrons revolve around the nucleus of the atom in specific orbits.

Question 3.
Proton and Electron:
Answer:

Proton	Electron
1. The proton is a positively charged particle	1. The electron is a negatively charged particle.
2 Protons are present in the nucleus of an atom.	2. Electrons revolve around the nucleus of the atom in specific orbits.

Question 4.
Atomic number and Atomic mass number:
Answer:

Atomic number	Atomic mass number
1. The number of electrons or protons in an atom is called the atomic number.	1. The sum of the number of protons and neutrons in the nucleus of an atom is called the atomic mass number.
2 All the isotopes of an element have the same atomic number.	2. Different isotopes of the same element have different mass numbers.
3. The atomic number is represented by the letter Z.	3. The atomic mass number is represented by the letter A.

Answer the following questions in one sentence each:

Question 1.
Name the particles which are present in the nucleus of an atom.
Answer:
Protons and neutrons are present in the nucleus of an atom.

Question 2.
State the relation between the number of protons, the number of neutrons and the atomic mass number (A) of an element.
Answer:
Atomic mass = Number of + Number of number (A) protons (p) neutrons (n)

Question 3.
Chlorine contains 17 protons and 18 neutrons. What is its atomic mass number?
Answer:
The atomic mass number of chlorine is 35.

Question 4.
Carbon contains 6 protons and 6 neutrons. State its atomic number and atomic mass number.
Answer:
The atomic number of carbon is 6 and the atomic mass number is 12.

Question 5.
State one use of isotopes of cobalt.
Answer:
Isotopes of Cobalt-60 are used in the treatment of cancer.

Question 6.
State one use of isotopes of i uranium.
Answer:
Isotopes of uranium are used for production of electrical energy.

Question 7.
Write the electronic configuration of oxygen.
Answer:
Electronic configuration of oxygen is 2, 6.

Question 8.
Write the electronic configuration of chlorine.
Answer:
Electronic configuration of chlorine is 2, 8, 7.

Question 9.
State the number of electrons in the L shell of lithium.
Answer:
There is one electron in the L shell of lithium.

Question 10.
State the number of electrons in the M shell of argon.
Answer:
There are 8 electrons in the M shell of argon.

Question 11.
State the number of electrons in the K shell of helium.
Answer:
There are two electrons in the K shell of helium.

Question 12.
Name isotopes of hydrogen.
Answer:
Hydrogen, Deuterium and Tritium are the isotopes of hydrogen.

Question 13.
Name two isotopes of carbon.
Answer:
[latex]{ }_{6}^{12} \mathrm{C}\) and ${ }_{6}^{14} \mathrm{C}$ are the isotopes of carbon.

Question 14.
Name two elements in which the K and L shells of an atom are completely filled with electrons.
Answer:
The elements are neon and argon.

Question 15.
From the symbol ${ }_{8}^{16} \mathrm{O}$, state the electronic configuration of oxygen and the atomic mass number of isotope oxygen.
Answer:
Electronic configuration of oxygen : 2, 6. Atomic mass number of oxygen : 16.

Question 16.
The atomic mass number of an element is 18, and the element contains 8 electrons. What is the number of protons and neutrons in it?
Answer:
Number of protons : 8, Number of neutrons : 10.

Question 17.
An atom contains 2 protons, 2 electrons and 3 neutrons. State its atomic number and atomic mass number.
Answer:
Atomic number: 2, Atomic mass number: 5.

Question 18.
How many electrons could there be in the outermost orbit of an element whose valency is 3?
Answer:
If the valency of an element is 3 then there is a possibility of 3 or 5 electrons in the outermost orbit.

Question 19.
Which element is used as fuel in atomic reactors?
Answer:
Isotopes of uranium are used as fuel in atomic reactors.

Question 20.
Name the place and the first nuclear reactor in India.
Answer:
Apsara at Bhabha Atomic Research Centre in Mumbai is the first nuclear reactor in India.

Answer the following questions:

Question 1.
Explain Dalton’s atomic theory.
OR
Write the postulates of Dalton’s atomic theory.
Answer:
Dalton’s atomic theory:

According to Dalton’s atomic theory matter is made up of atoms and atoms are indivisible and indestructible.
All atoms of an element are alike while different element have different atom with different mass.

Try this:

Question a.
Take a solid ball and a Bundi Laddu. Press both these spheres with your palms. What did you find?
Answer:
Solid ball does not break and Bundi Laddu breaks into pieces if you press hard.

Question b.
Cut the solid ball with a sharp knife. What did you find?
Answer:
There is no cavity inside the ball.

Question 2.
How will you think about atomic mass distribution according to Thomson’s I model? Whether this distribution is uniform or non uniform as per Dalton’s atomic theory?
(Use your brainpower!
Answer:
In Thomson’s model the distribution of atomic mass is uniform. Dalton’s atomic theory does not say anything about atomic mass distribution.

Question 3.
If the striker flicked by you misses the coin that you aimed at, where would the striker go?
Can you tell?
Answer:
The striker will continue to move practically with the same velocity till it strikes some other coin or the edge of the board or enter the pocket.

Question 4.
If the striker hits the coin, in which direction would it go? Straight forward to a side or in the reverse direction?
Answer:
Striker may go straight forward or it may be deflected depending upon the exact direction of the motion of the striker.

Question 5.
Draw a neat labelled diagram of Thomson’s atomic model.
Answer:

Question 6.
What were the conclusions drawn from the alpha particle experiment performed hy Rutherford?
Answer:
On the basis of the alpha particle experiment the following conclusions were drawn by Rutherford:

An atom has tiny, dense positively charged nucleus at centre of an atom.
Most of the mass of the atom is concentrated in the nucleus.
Negatively charged particles called electrons revolve around the nucleus.
The total negative charge on all the ; electron is equal to the positive charge on ‘ the nucleus. As the opposite charges are balanced, the atom is electrically neutral.
There is an empty space between the i revolving electron and the atomic nucleus.

Question 7.
Explain Rutherford’s atomic model.
Answer:

An atom has tiny, dense, positively charged core called the nucleus.
Most of the mass of the atom is concentrated in the nucleus.
Electrons bear negative charge. They revolve around the nucleus in orbits.
The structure of an atom may be regarded as a miniature of the solar system, the nucleus as the sun and the electrons as the planets.

Question 8.
Which discovery did point out that an atom has internal structure?
(Use your brainpower!
Answer:
The discovery of radioactivity (1896) pointed out that an atom has internal structure.

Question 9.
What is the difference between the solid atom in Dalton’s atomic theory and Thomson’s atomic model?
(Use your brain power!
Answer:
The solid atom in Dalton’s atomic theory is a single particle it does not have any structure and also does not have any constituents. In Thomson’s model, atom is made of positive and negative charges. Thus it is not a single particle. It has constituents and has internal structure.

Question 10.
Explain the difference between the distribution of positive charge in Thomson’s atomic model and Rutherford’s atomic model.
(Use your brain power!
Answer:
According to Thomson’s atomic model, the atom is a homogeneous sphere of positive charge. According to Rutherford’s atomic model, the positive charge is concentrated in the nucleus.

Question 11.
What is the point difference between the place of electron in the atomic models of Thomson and Rutherford?
(Use your brain power!
Answer:
According to Thomson’s atomic model, the negatively charged electrons are embedded in a gel of positive charge and they are stationary. According to Rutherford’s atomic model, the negatively charged electrons revolve around the nucleus.

Question 12.
What is the thing which is present in Rutherford’s atomic model and not present in Dalton’s and Thomson’s atomic models?
(Use your brain power!
Answer:
1. Dalton’s atomic model:
Dalton’s atomic theory does not tell anything about the structure of the atom. There is no mention of electron in Dalton’s atomic theory.

Rutherford’s atomic model:
Rutherford’s atomic model tells about the structure of the atom, i.e. the electron revolving around the nucleus.

2. Thomson’s atomic model:
The electrons are embedded in a gel of positive charge. Here the electrons are stationary and there is no concept of nucleus.

Rutherford’s atomic model:
In Rutherford’s atomic model, the electrons are not stationary, they revolve around the nucleus which is positively charged.

Question 13.
Explain Niels Rohr’s atomic model.
OR
Write the postulates of Bohr’s atomic model.
Answer:
The important postulates of Bohr’s atomic model are as follows:

The electrons revolving around the atomic nucleus lie in the concentric circular orbits at certain distance from the nucleus.
Energy of an electron is constant while it is in a particular orbit.
When an electron jumps from an inner orbit to an outer orbit it absorbs specific amount of energy, and when it jumps from an outer orbit to an inner orbit it emits specific amount of energy.
The energy emitted or absorbed during these transitions is equal to energy difference between the initial state and the final state of the electron.

Question 14.
How many types of subatomic particles are found in atom?
Use your brainpower!
Answer:
There are three types of subatomic particles found in atom, viz. the proton, neutron and electron.

Question 15.
Which subatomic particles are electrically charged?
Use your brain power!
Answer:
The proton is a positively charged subatomic particle and the electron is a negatively charged particle.

Question 16.
Which subatomic particles are present in the nucleus?
Use your brain power!
Answer:
The proton and neutron are present in the nucleus.

Question 17.
Where are electrons revolving around the nucleus placed?
Use your brain power!
Answer:
Electrons revolve in the discrete orbits around the nucleus.

Question 18.
State the characteristics of the neutron.
Answer:

The neutron is electrically neutral and is denoted by the symbol ‘N’.
It is present in the nucleus along with the proton.
The mass of the neutron is almost equal to lu which is almost equal to that of the proton.

Question 19.
State the characteristics of protons.
Answer:

Protons are positively charged particles and are denoted by the symbol ‘P’.
They are present in the nucleus of an atom.
The mass of the proton is very nearly equal to lu which is almost equal to that of the hydrogen atom.
All the elements contain protons.

Question 20.
State the characteristics of electrons.
Answer:

Electrons are negatively charged particles and are denoted by the symbol ‘e’.
They have negligible mass.
They revolve around the nucleus in certain discrete orbits.
In an atom, the number of electrons is equal to the number of protons in its nucleus (Z).

Question 21.
The symbol used for oxygen is ‘O’. There are 8 protons and 8 neutrons in its nucleus. From this determine the 1 atomic number (Z) and mass number (A) of oxygen and arrange these in a 1 conventional symbol.
Use your brain power!
Answer:
Atomic mass number
= Protons + Neutrons
= 8 + 8
Atomic mass number = 16
Atomic number, i.e. the proton number = 8
The conventional symbol = $\mathrm{A} \mathrm{O}$
Z = Atomic number
i.e. number of protons is 8.
A = Atomic mass number = 16.
The conventional symbol = ${ }_{8}^{16} \mathrm{O}$.

Question 22.
Atomic number of carbon is 6. How many electrons are there in a carbon atom?
Use your brainpower!
Answer:
The atomic number of carbon, i.e. the proton number of carbon is 6.
The number of electron in the extranuclear part is equal to the number of protons in the nucleus.
∴ The number of electrons in a carbon atom = 6.

Question 23.
A sodium atom contains 11 electrons. What is the atomic number of sodium?
Use your brain power!
Answer:
The number of electron in the extranuclear part is equal to the number of protons, i.e. atomic number. The atomic number of sodium is 11.

Question 24.
The atomic number and mass number of magnesium are 12 and 24 respectively. How will you show this by the convention symbol?
Use your brainpower!
Answer:
The atomic number, atomic mass number and the symbol of an element are written as:

${ }_{12}^{24} \mathrm{Mg}$ the conventional symbol for magnesium.

Question 25.
The atomic number and mass number of calcium are 20 and 40 respectively. Deduce the number of neutron present in the calcium nucleus.
Use your brain power!
Answer:
There are 20 neutrons in the nucleus of calcium.
[Note: The number of neutrons N = A – Z = 40 – 20 = 20]

Question 26.
Write a note on distribution of electrons in orbits.
OR
What is the maximum number of ( electrons that can be accommodated in each of the orbits (shells) K, L, M, N, etc.?
Answer:
The number of maximum electrons in different orbits of the atom are fixed. The orbit (shell) closest to the nucleus is: given the number 1, the next orbit the ; number 2… etc. The orbits one are designated ; by letters K, L, M, N,… corresponding to the shell numbers n = 1, 2, 3, 4, … etc. The maximum number of electrons in a given orbit is 2n², when n is the number of orbit (shell), thus the first shell has the capacity of 2 electrons, the second 8, the third 18, the fourth 32 and so on. The electrons in the K shell have minimum energy. The electrons in the subsequent shells possess higher energy.

Question 27
There is a similarity in atomic structure and solar system. The planets revolve around the sun due to the gravitational force. Which force might be acting in the atomic structure?
Can you tell?
Answer:
The electric force might be acting in the atomic structure. In the atomic structure, electric force is much stronger than gravitational force.
[Note: Here the gravitational force is very very small compared to the electric force, therefore, the gravitational force can be ignored.]

Question 28.
Positively charged proton are together in the nucleus. What might be, one of the function of the neutrons in the nucleus?
Can you tell?
Answer:
One of the function of the neutrons in the nucleus is to keep the protons and neutrons together by nuclear force.

Question 29.
What do you understand by electronic configuration?
Answer:
The shellwise distribution of the electron in an atom of an element is called the electronic configuration.?

Question 30.
Write the electronic configuration of the following elements:
(1) Hydrogen, (2) Magnesium. (3) Aluminium, (4) Phosphorus, (5) Sulphur.
Answer:

Question 31.
Use the following molecular formulae to determine the valencies of H, Cl, O, S, N, C, Br, I, Na.
Molecular formulae – H₂, HCl, H₂O, H₂S, NH₃, CH₄, HBr, HI, NaH.
Can you recall?
Answer:

Question 32.
Draw suitable diagrams to show the electronic configuration of the atoms of the following elements: Hydrogen, helium, carbon, neon, sodium, chlorine.
Answer:

Question 33.
What are the symbols used for the shells which accommodate the electrons in various atoms?
Use your brain power!
Answer:
The symbols used for the shells which accommodate the electrons are K, L, M, N, … respectively.

Question 34
What is the symbol and ordinal number of the innermost shell?
(Use your brain power!
Answer:
The symbol of the innermost shell is K and ordinal number of the innermost shell is 1.

Question 35.
Write symbol of electron distribution in shell of fluorine atom?
Use your brain power!
Answer:
Symbol for fluorine atom = F,
Electronic configuration of fluorine $\begin{array}{l}\mathrm{K} \\2\end{array}$, $\begin{array}{l}\mathrm{L} \\7\end{array}$.

Question 36.
Which is the outermost shell of fluorine atom?
Use your brain power!
Answer:
The outermost shell of fluorine atom is L.

Question 37.
Which is the outermost shell of sodium atom?
Use your brain power!
Answer:
The outermost shell of sodium atom is M shell.

Question 38.
Which is the outermost shell of hydrogen atom?
Use your brain power!
Answer:
The outermost shell of hydrogen is K shell.

Question 39.
What is meant by the atomic number (Z) of an element?
(Use your brain power!
Answer:
Atomic number (Z): The number of electrons or protons in an atom is called the atomic number. It is denoted by Z.

Question 40.
Atomic numbers (Z) of some elements are given here. Write down the number of electron present in the outermost shell of each of them.
Use your brain power!
Answer:

Question 41.
The number of electrons of some elements is given here. By using it write the electronic configuration, number of valence electron and valency of the respective elements.
Use your brain power!
Answer:

Question 42.
Why are the atomic numbers and atomic mass numbers always in whole numbers?
Use your brain power!
Answer:
The total number of protons and neutrons in the nucleus of the atom is called the atomic mass number (A). The number of electrons or protons in an atom is called the atomic number (Z). Both protons and neutrons are whole numbers, therefore, atomic numbers and atomic mass numbers are always in whole numbers.

Question 43.
Sulphur contains 16 protons and 16 neutrons. What would be its atomic number and mass number?
Use your brain power.
Answer:
The atomic number of sulphur is 16 and the atomic mass number is 32.

Question 44.
State the uses of isotopes.
Answer:
Isotopes of some elements are radioactive. Isotopes are used in various fields such as industry, agriculture, medicine, research field.

Isotopes of uranium is used for nuclear fission and production of electricity.
Cobalt – 60 are used in the treatment of cancer.
Iodine – 131 is used in the treatment of goitre.
The radioactive isotopes, Sodium – 24 are used for detection of cracks (leakage) in the underground pipes.
Radioactive isotopes are used for food preservation from microbes.
The radioactive C – 14 is used for determining the age of archaeological objects.

Question 45.
Write a note on nuclear reactor.
Answer:
1. A machine that generates electricity on large scale by using atomic energy is called a nuclear reactor. In a nuclear reactor, the nuclear energy in atom is released by bringing about nuclear reactions on the nuclear fuel.

2. When uranium – 235 is bombarded with a slow speed neutron, it undergoes nuclear fission. Various elements are produced. For example: Krypton – 92 and Barium – 141 along with 2 to 3 neutrons are emitted on fission, these neutron have high speed. Their speed is reduced and they are used for bombarding more Uranium – 235 nuclei.

The process is repeated many times. In this way a chain reaction of nuclear fission takes place (See the figure). A large amount of nuclear energy is released during a chain reaction of fission. The chain reaction is controlled to prevent the probable explosion.

Neutrons are slowed down using graphite or heavy water as moderator. The chain reaction is controlled by absorbing neutron with the help of rods of boron, cadmium and beryllium. The heat produced in the fission is taken out by water as coolent. Water is converted into steam. The available heat is used to drive turbines to produce electricity.

Give scientific reasons:

Question 1.
In Rutherford’s experiment, some alpha particles colliding with the thin gold foil are turned back.
Answer:
1. All the positive charges in an atom is concentrated in a very small region at the centre of the atom. This region is called the nucleus. Electrons revolve around the nucleus, but most of the atom is empty. Alpha particles are positively charged.

2. When a thin sheet of gold is bombarded by alpha particles, most of the particles pass through it without deviation as the atom is almost empty. But some alpha particles move directly towards the positive nuclei, collide with them and due to the electric repulsion, turn back. Thus, in Rutherford’s experiment, some alpha particles colliding with the thin gold foil are turned back.

Question 2.
Two electrons in helium atom are placed in only one shell while three electrons in lithium atom occupy two shells.
Answer:
1. The electronic configuration of helium is (2). It indicates that helium atom has two electrons. Both the electrons are accommodated in the K shell. The maximum capacity of the K shell is two electrons and is maintained in all the elements. Hence, two electrons in helium are placed in only one shell.

2. The electronic configuration of lithium is (2, 1). It indicates that lithium atom has three electrons. The first shell K accommodates two electrons, i.e., the maximum capacity of the K shell. The remaining electron is accommodated in the next shell, i.e., the L shell. Thus, three electrons in lithium occupy two shells (K and L).

Complete the following:

Question 1.
Complete the table by putting tick mark in appropriate box.
Answer:
Types of substances:

Question 2.
Complete the table:
Answer:

Write the maximum number of electron in a shell using the above table. K Shell : 2, L Shell : 8, M Shell : 18, N Shell : 32.

Question 3.
Complete the table:
Answer:
Electronic configuration of some elements:

Question 4.
Complete the following table:
Answer:
Relationship between valency and electronic configuration:

Question 5.
In table 4 column you have written of that element? How many electrons identified valency from its molecular are used to complete the octet? formulae. When the number of the valency electrons in an element ‘x’ is 4 or less than 4, does ‘x’ match with the valency of that element?
Use your brain power!
Answer:
When the number of the valence electrons in an element x is 4 or less than 4, then x matches with the valency of that element.

Question 6.
When the number of the valence electrons in an element ‘x’ is 4 or more than 4, does’(8 – x)’ match with the valency of that element? How many electrons are used to complete the octet?
(Use your brain power!
Answer:
When the number of the valence electrons in an element x is 4 or more than 4, then (8-x) matches with the valency of that element. (8-x) electrons are used to complete the octet.

Question 7
Complete the table:
Answer:

Isotopes	Proton number	Neutron number
${ }_{1}^{1} \mathrm{H}$	1	–
${ }_{1}^{2} \mathrm{H}$	1	1
${ }_{17}^{35} \mathrm{Cl}$	1	2
${ }_{17}^{35} \mathrm{Cl}$	17	18
${ }_{17}^{37} \mathrm{Cl}$	17	20

8th Std Science Questions And Answers:

Human Body and Organ System Class 8 Science Chapter 11 Questions And Answers Maharashtra Board

February 6, 2025February 5, 2025 by Bhagya

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 11 Human Body and Organ System Notes, Textbook Exercise Important Questions and Answers.

Std 8 Science Chapter 11 Human Body and Organ System Question Answer Maharashtra Board

Class 8 Science Chapter 11 Human Body and Organ System Question Answer Maharashtra Board

1. Find out my partner.

Question a.

Group ‘A’	Group ‘B’
1. Heartbeats	a. 350 ml
2. RBC	b. 7.4
3. WBC	c. 37° C
4. Blood donation	d. 72 per min
5. Normal body temperature	e. 50 – 60 lakh/mm³
6. pH of oxygenated blood	f. 5000 – 6000 per mm³

Answer:

Group ‘A’	Group ‘B’
1. Heartbeats	d. 72 per min
2. RBC	e. 50 – 60 lakh/mm³
3. WBC	f. 5000 – 6000 per mm³
4. Blood donation	a. 350 ml
5. Normal body temperature	c. 37° C
6. pH of oxygenated blood	b. 7.4

2. Complete the following table.

Question a.

Answer:

3. Draw neat and labeled diagrams.

Question a.
Respiratory system.
Answer:

Question b.
Internal structure of heart.
Answer:

4. Explain with reasons.

Question a.
Human blood is red coloured.
Answer:
The red colour of human blood is due to hemoglobin which is a red coloured conjugated protein with iron that is present on the red blood cells. Therefore, it looks red.

Question b.
Upward and downward movement of diaphragm occurs consecutively.
Answer:
The breathing movements are possible due to contraction and relaxation of the diaphragm. The rib muscles also help in these movements. When the ribs rise and diaphragm is lowered at the same time, then there is a decrease in pressure on lungs.

This causes movement of air into the lungs at the time of inhalation. On the other hand, when ribs come back to their normal position and diaphragm is risen, then pressure on the lungs increases. This causes movement of the air out of the body through the nose in the form of exhalation. These movements are possible only due to consecutive upward and downward movement of the diaphragm.

Question c.
Blood donation is considered to be superior of all donations.
Answer:
Blood cannot be manufactured by any artificial chemical process. The only way to obtain blood is by donations of blood from a live donor. Blood is needed at times of emergency. The life of person can be saved if timely blood transfusion is given to the needy victim or a patient. Since such donation can save a valuable human life, it is called superior of all donations.

Question d.
Person with ‘O’ blood group is considered as ‘universal donor’.
Answer:
Person with ‘O’ blood group does not have any antigen on his/her RBCs. The ‘O’ type blood thus cannot cause clotting reactions in the body of the recipients. Such persons with ‘O’ blood group can donate blood to any person having any blood group therefore they are considered as ‘universal donor’.

Question e.
Food must have limited amount of salts.
Answer:
More salt in diet means more sodium ions. These extra sodium salts cause rise in blood pressure. Such condition is called hypertension. This condition can be dangerous and fatal in some cases. Therefore, one must keep control over sodium content of the food.

5. Answer the following questions in your own words.

Question a.
Explain the functional correlation of circulatory system with respiratory, digestive and excretory system.
Answer:
1. Three systems viz. respiratory, digestive and circulatory always work in coordination.
2. Digestive system helps in breaking down complex food molecules into simple soluble nutrients at the end of the digestion process.
3. The soluble nutrients are absorbed in the circulating blood in the villi of the intestine.
4. The blood carries these nutrients to each cell during its circulation.
5. The respiratory system helps the oxygen from the air to be absorbed in the blood.
6. This process takes place in alveolus present in lungs. The oxygen is absorbed in the blood and through haemoglobin it is taken to every cell of the body. At the same time the unwanted carbon dioxide produced in each cell is given out in a process of gaseous exchange.
7. The soluble nutrients, and chiefly glucose is metabolized with the help of oxygen-producing energy. Thus, all the three systems bring about coordinated functions to keep the body alive.

Question b.
Explain the structure and function of human blood.
Answer:
I. Structure, i.e. components of the human blood: Human blood is a fluid connective tissue consisting of blood plasma and blood corpuscles suspended in it.

1. Plasma: Plasma is the fluid part of the blood which is pale yellow in colour. It is slightly alkaline in nature. It has 90-92% water, 6-8 % proteins and 1-2 % inorganic salts.
It contains proteins such as albumin, globulin, fibrinogen, etc. There are inorganic ions such as Ca, Na and K.

2. Blood cells:
a. Blood cells are mainly of three types, viz. RBCs, WBCs and blood platelets. They are produced in the red bone marrow.
b. RBCs are small, circular and enucleated cells. They are full of haemoglobin which is essential in transporting oxygen. RBCs are red blood cells which are 50 to 60 lakh per cubic millimetre. Their life span is 100 to 127 days.
c. WBCs are large, nucleated and colourless. They are of five subtypes, viz. neutrophils, basophils, eosinophils, monocytes and lymphocytes. They are 5 to 10 thousands per millimetre of blood.
d. Platelets are very small disc-shaped blood cells which are 2.5 to 4 lakh per cubic millimetre of blood.

II. Function of human blood:

1. Transport functions:

Gases: Oxygen is carried via blood from lungs to cells in various parts of body and carbon dioxide from tissues to lungs.
Nutrients: Simple nutrients like glucose, amino acids, fatty acids are taken up by blood from wall of alimentary canal and transported up to each cell in the body.
Waste materials: Nitrogenous wastes like ammonia, urea, creatinine are released by tissues into blood which carries those to kidney for excretion.
Enzymes and hormones: Blood transports the enzymes and hormones from the site of their production to the site of their action.

2. Protection: Antibodies are produced in the blood and they protect the body from microbes and other harmful particles.
3. Thermoregulation: Body temperature is maintained constant at 37 °C by vasodilation and vasoconstriction.
4. Maintaining the balance of minerals like Na, K in the body.
5. If bleeding occurs at the injury, platelets and a protein called fibrinogen of the blood form a clot and seal the injury.
6. Functions of blood cells:

RBCs: With haemoglobin it carries out transport of respiratory gases.
WBCs: Soldiers of the body. Produce antibodies and give immunity to body.
Platelets: Help in blood clotting.

Question c.
Explain the importance and need of blood donation.
Answer:
Blood can never be synthesized artificially. There is no substitute for natural blood. Every healthy person possesses about 5 litres of blood in his or her body. In case of haemorrhage i.e. blood loss, the blood volume may reduce which can result into threat to life. Moreover, the loss of blood should be immediately taken care of, otherwise it may cost the life.

Therefore blood transfusion is very crucial in case of victims of accidents, patients of surgeries or mothers who suffer from blood loss during childbirth (parturition). Some diseases such as thalassemia, blood cancer, etc. also need regular transfusions. Therefore, blood is always needed in many such conditions. Blood donation is only option for such transfusions.

6. Explain the differences.

Question a.
Arteries and veins.
Answer:

Arteries	Veins
1. Arteries carry blood away from the heart to the tissues of the body.	1. Veins carry blood from the tissues of the body back to the heart.
2. Arteries are located deeper within the body.	2. Veins are usually located superficially beneath the surface of the skin.
3. Arteries are thick walled	Veins are thin walled.
4. Arteries do not have valves.	4. Veins have valves.
5. Arteries would generally remain open if blood flow stopped, due to their thick muscular layer.	5. Veins would collapse if blood flow stops.
6. Except pulmonary artery, all arteries carry oxygenated blood.	6. Except pulmonary vein, all veins carry deoxygenated blood.
7. Arteries are more muscular than veins, which helps in transporting blood that is full of oxygen efficiently to the tissues.	7. Veins are less muscular than arteries, but contain valves to help keep blood flowing in the right direction, usually toward the heart.
8. There is maximum blood pressure in the arteries.	8. There is minimum blood pressure in the veins.

Question b.
External and internal respiration.
Answer:

External respiration	Internal respiration
1. Intake of air from the outside into the body and release of air from the body to outside is called external respiration.	1. Exchange of gases between cells and tissue fluid is called internal respiration.
2. External respiration occurs between cells and the external environment.	2. Internal respiration occurs only in the cells of the body.
3. It involves processes of inspiration and expiration.	3. It involves movement of O₂ from blood into tissue fluid and movement of CO₂from tissue.
4. External respiration involves breathing and gaseous exchange.	4. Internal respiration involves neither breathing nor gaseous exchange.
5. Oxygen combines with haemoglobin in external respiration.	5. Chemical reactions occur in the cells to form energy.

7. Which health parameters of blood donor should be checked?

Question a.
Which health parameters of blood donor should be checked?
Answer:
Blood donor should be healthy. He or she should have good haemoglobin’s content. The RBC and WBC count should also be normal. They should not carry any parasites in their blood such as malarial parasite or dengue virus. The donor should not be HIV positive or should not have any infectious diseases. He should not have any addictions such s drug-abuse or alcohol consumption.

8. Fill in the blanks using appropriate words given in the bracket.
(hemoglobin, alkaline, diaphragm, red bone marrow, acidic, voluntary, involuntary,)

Question a.
RBCs of the blood contain ……….., an iron compound.
Answer:
RBCs of the blood contain haemoglobin, an iron compound.

Question b.
……………….. is present between thoracic and abdominal cavity.
Answer:
Diaphragm is present between thoracic and abdominal cavity.

Question c.
Cardiac muscles are …………… .
Answer:
Cardiac muscles are involuntary.

Question d.
pH of oxygenated blood is …………… .
Answer:
pH of oxygenated blood is alkaline.

Question e.
Production of RBCs occurs in ……………… .
Answer:
Production of RBCs occurs in red bone marrow.

8. Find odd one out.

Question a.
A, O, K, AB, B.
Answer:
K (All others are blood groups.)

Question b.
Blood plasma, platelets, blood transfusion, blood corpuscles.
Answer:
Blood transfusion (All others are components of blood.)

Question c.
Trachea, alveoli, diaphragm, capillaries.
Answer:
Capillaries (All others are parts of respiratory system. Capillaries exist throughout the body.)

Question d.
Neutrophils, globulins, albumins, prothrombin.
Answer:
Neutrophils (All others are proteins present in the plasma.)

10. Read the following paragraph and identify the disease.

Today, her child became one and half year old. However, that child does not seem to be healthy and happy. It was continuously crying and gradually becoming weak. It has shortness of breath. Its nails have become blue.
Answer:
The heart of the child is not functioning properly. Bluish nails show lack of oxygen, thus the baby may be suffering also from respiratory problems.

11. Your neighboring uncle has been diagnosed with hypertension. What should he do to keep his blood pressure within normal range?

Question a.
Your neighboring uncle has been diagnosed with hypertension. What should he do to keep his blood pressure within normal range?
Answer:
Hypertension has many causes. Try to find out what is the exact cause. Is it lack of exercise, obesity, lots of fast and junk food consumption, over-intake of salt, mental tension, etc. He should visit a proper physician and take prescribed blood pressure control medicines. He should never miss a single tablet. He should avoid salty and preserved food. He should practice yoga and meditation. He should also undertake some stress- management techniques.

Project:

Question a.
Collect information about various modern treatments on heart diseases.

Class 8 Science Chapter 11 Human Body and Organ System Important Questions and Answers

Rewrite the statements after correcting them:

Question 1.
Cells need supply of insoluble nutrients and oxygen for the energy production.
Answer:
Cells need the supply of soluble nutrients and oxygen for the energy production.

Question 2.
Respiratory system and respiration begins with mouth.
Answer:
Respiratory system and respiration begins with nose.

Question 3.
A lung is present on either sides of heart in abdominal cavity.
Answer:
A lung is present on either sides of heart in thoracic cavity.

Question 4.
Continuous upward and downward movement of diaphragm is necessary to bring about the beating of heart.
Answer:
Continuous upward and downward movement of diaphragm is necessary to bring about the breathing.

Question 5.
Blood vessels which carry the blood away from heart are called veins.
Answer:
Blood vessels which carry the blood away from heart are called arteries.

Question 6.
William Harvey described the blood groups in man.
Answer:
William Harvey described the mechanism of circulation in the body.

Question 7.
Capillaries unite together to form the arteries.
Answer:
Capillaries unite together to form the veins.

Match the columns/Find out my partner:

Question 1.

Group ‘A’	Group ‘B’
1. William Harvey	a. Blood group AB.
2. Carl Landsteiner	b. A, B, O blood group system.
3. Decastello and Sturli	c. Mechanism of circulation of blood.

Answer:

Group ‘A’	Group ‘B’
1. William Harvey	c. Mechanism of circulation of blood.
2. Carl Landsteiner	b. A, B, O blood group system.
3. Decastello and Sturli	a. Blood group AB.

Complete the following table:

Question 1.

Answer:

Type	Systolic pressure	Diastolic pressure
Normal blood pressure	90 – 119 mmHg	60 – 79 mmHg
Primary hypertension	120 – 139 mmHg	80 – 89 mmHg
Hypertension stage – I	140 – 159 mmHg	90 – 99 mmHg
Hypertension stage – II	> 160 mmHg	> 100 mm

Define the following terms:

Inhalation: Inhalation is taking in air through the nose from the surrounding
Exhalation: Exhalation is giving out the air back to the outer environment.
External respiration: The processes of inhalation and exhalation both together are called external respiration.
Internal respiration: Exchange of gases between cells and tissue fluid is called internal respiration.
Cellular respiration: Production of energy in the form of ATP from oxidation of glucose and other soluble nutrients is called cellular respiration.
Thermoregulation: Maintenance of the body temperature to a constant level by performing vasoconstriction or vasodilation is called thermoregulation.
Blood pressure: Pressure exerted by the flowing blood on the blood vessel wall is called blood pressure.
Systolic pressure: The maximum blood pressure exerted by the flowing blood when the heart is contracting is called systolic pressure.
Diastolic pressure: The minimum blood pressure exerted by the flowing blood when the heart is not contracting but receiving (i.e. relaxing) the blood is called diastolic pressure.
Hypertension or High Blood Pressure: The blood pressure value of 140 – 159 mm Hg which is more than the normal blood pressure is called hypertension or high blood pressure.
Sphygmomanometer: The instru¬ment used for measuring blood pressure is called sphygmomanometer.
Hematology: The branch of medical science in which the blood, haemapoietic organs (organs that produce blood cells) and blood disorders are studied is called haematology.

Answer the following questions in one or two sentences each:

Question 1.
What are the heart sounds and why are they produced?
Answer:
There are two types of heart sounds, one is ‘lubb’ and other is ‘dub’. These are produced due to closure of the heart valves.

Question 2.
What is blood circulation?
Answer:
The process of pumping the blood to all the parts of the body and bringing it back again to the heart is called the blood circulation.

Question 3.
Name any four proteins present in the blood plasma.
Answer:
The proteins present in the blood plasma are albumin, globulins, fibrinogen and prothrombin.

Question 4.
Which inorganic ions control the function of muscles and nerves?
Answer:
Calcium, sodium and potassium control the functions of muscles and nerves.

Question 5.
What is the basis on which blood group is determined?
Answer:
The antigen present on the RBCs: and the antibodies present in the plasma of I the blood determine the type of blood group. The genes of parents are responsible for the type of blood group that the child inherits.

Question 6.
Under which conditions, blood is required for donation?
Answer:
Whenever there is hemorrhage, the patient requires blood. Such patients are accident victims, those who excessively bleed, women during childbirth (parturition) and for patients undergoing surgeries.

Question 7.
How much blood is collected from a person during donation?
Answer:
About 350 ml of blood is collected from a person during donation.

Question 8.
When is National Voluntary Blood Donation Day observed?
Answer:
National Voluntary Blood Donation Day is observed on 1st October every year.

Explain the differences:

Question 1.
Atria and ventricles:
Answer:

Atria	Ventricles
1. Atria are the upper chambers of the heart.	1. Ventricles are the lower chambers of the heart.
2. Atria are the smaller receiving chambers.	2. Ventricles are the larger distributing chambers.
3. Atria are thin walled chambers having lesser blood pressure.	3. Ventricles are thick walled chambers with greater blood pressure.
4. Atria do not have inlet valves.	4. Ventricles have inlet valves.
5. Right atrium receives deoxygenated blood from whole body through the inferior vena cava (lower body), superior vena cava (from upper body). It pumps blood into right ventricle.	5. Right ventricle pumps deoxygenated blood received from right atrium to lungs for oxygenation which is known as pulmonary circulation.
6. Left atrium receives oxygenated blood from lungs through pulmonary veins. It pumps blood into left ventricle.	6. Left ventricle pumps oxygenated blood received from left atrium to whole body. This is called systemic circulation.

Question 2.
RBCs and WBCs:
Answer:

RBCs	WBCs
1. RBCs are red in colour due to haemoglobin present in them.	1. WBCs are colourless as there is no pigment in them.
2. RBCs are produced in red bone marrow.	2. WBCs are produced mostly in bone marrow. But they are also produced in lymph nodes, spleen, etc.
3. RBCs are smaller in size and rounded in .shape.	3. WBCs are larger in size and are of different shapes.
4. RBCs have an average lifespan of 120 days.	4. Life span of WBCs vary according to their role. They have a life span from a few days to 3 weeks.
5. Normal RBC count is 50 – 60 lakh RBCs per cubic mm. of blood.	5. Normal WBC count is 5 thousands to 10 thousands per cubic mm. of blood.
6. Their function is to transport the respiratory gases (Oxygen and Carbon Dioxide).	6. Their main function is to produce antibodies and fight against the infections. Thus they are called soldiers of the body.

Give scientific reasons:

Question 1.
A very large number of alveoli is present in lungs, which are covered over by capillary network.
Answer:
Due to very large number of alveoli the surface area of the lungs is increased many a times for the gaseous exchange. The alveoli are covered over by capillary network for rapid gaseous exchange. The oxygen is taken in the body and at the same time carbon dioxide is given out of the body only by the gaseous exchange occurring at the alveolar surface.

Question 2.
Heart is covered by double layered pericardial membrane.
Answer:
Pericardium is the protective double membrane that covers the heart. In between the two layers of this membrane there is protective fluid. The pericardium and the fluid together protect the heart from friction and mechanical shock. Since heart is a vital organ, it is well protected by such pericardial membrane.

Question 3.
Veins are provided with valves.
Answer:
Valves prevent the backflow of the blood. Blood in the veins is not under great pressure so it is likely that it may flow back. But valves prevent such movements. Therefore they are provided with valves.

Write short notes on the following:

Question 1.
Cellular respiration:
Answer:

During respiration, the glucose molecules along with some other soluble nutrients are slowly oxidized with the help of oxygen in each cell.
In this process the energy is released in the form of ATP, CO₂ and water vapours are produced.
These products are not needed for the body and hence given out of the body in exhalation.
This process of cellular respiration is shown by the following reaction:
C₆H₁₂O₆ + 6O₂ = 6CO₂ + 6H₂O + Energy (38ATP)

Question 2.
Lung:
Answer:

Pair of lungs is the main respiratory organ in the human body. They are located in thoracic cavity.
They are present on either sides of heart.
Each lung has double layered pleural membranes.
Trachea bifurcates into two bronchi. Each bronchus enters lung on its side and S divide and re-divide into fine bronchioles.
At the end of each bronchiole there is alveolus. Alveolus is surrounded by capillary network.
Each alveolus is extremely thin walled and hence gaseous exchange can occur through diffusion here. Due to thousands of alveoli, the lung surface is increased many a times.
Deoxygenated blood coming from heart by pulmonary arteries is purified here in the lungs.
It is mixed with oxygen due to gaseous exchange and returned back to the heart by pulmonary veins. Lungs thus continuously help in oxygenation of blood with the help of all of the alveoli.

Question 3.
Diaphragm:
Answer:

Diaphragm is a muscular partition that divides the thoracic and abdominal cavity.
Located at the base of thoracic cage, it is very important in breathing movements.
Diaphragm can undergo consecutive upward and downward movements.
These movements along with movements of thoracic cage cause rise and fall of the pressure in the thoracic cavity.
Rising up of ribs and lowering of diaphragm causes the decrease in air pressure which makes the air to move into the lungs through nose. This is inhalation.
When the pressure rises in the thoracic cavity again, the air is given out. This is exhalation.
This is caused due to ribs returning to their original position and rising diaphragm. This simultaneously increases the pressure in thoracic cavity.

Question 4.
Structure of human heart:
Answer:

Human heart is four chambered muscular organ.
The size of the heart is about one’s own fist and its weight is about 360 gm.
For protection, it is covered over by double-layered pericardium.
The wall of the heart is made up of cardiac muscles which are involuntary in nature. They have the capacity of rhythmic beating.
The upper two chambers are called right and left atrium and lower two chambers are called right and left ventricle.
Between right atrium and right ventricle there is tricuspid valve which guards the opening. Similarly between left atrium and left ventricle there is bicuspid valve.
On entire right side of the heart there is deoxygenated blood.
On entire left side of the heart there is oxygenated blood.
Right atrium receives deoxygenated blood by superior and inferior vena cava. These two major veins bring deoxygenated blood from entire body to the heart.
Left atrium receives oxygenated blood from lungs by pulmonary vein.
Right ventricle sends the deoxygenated blood to lungs for oxygenation, through pulmonary artery.
Left ventricle supplies oxygenated blood to entire body through systemic aorta.

Question 5.
Human Blood Groups:
Answer:

The A, B, O blood group system is the most popular and medically important blood group system of human beings.
The blood group is determined due to antigenic protein present on the RBCs and the antibody present in the plasma.
The four main groups of human blood are A, B, AB and O.
According to the presence or absence of Rh antigen the blood groups are further said to be Rh-positive or Rh-negative.
This makes total eight blood groups which are taken into consideration at the time of blood transfusions.
Blood groups are dependent on genes and are thus hereditary in nature.

Answer the following:

Question 1.
How do the organisms like amoeba, earthworm, cockroach, plants, various aquatic animals, bird, respire? Prepare a chart.
Answer:

Diagram – based questions:

Question 1.
Sketch and label structure of alveolus showing gaseous exchange.
Answer:

Question 2.
Sketch and label artery and vein showing structural difference between the two.
Answer:

Question 3.
Draw a diagram to show formation of capillaries. Also show how capillaries form a vein.
Answer:

MCQs based on experiments:

I. Human respiratory system:

Question 1.
From which organ does respiratory system of man begin?
(a) Trachea
(b) Lungs
(c) Alveolus
(d) Nose
Answer:
(d) Nose

Question 2.
Which of the statement given below is correct?
(a) Wind pipe is present in front of food pipe.
(b) Food pipe is present in front of wind pipe.
(c) Wind pipe and food pipe are not near each other.
(d) Wind pipe is same as oesophagus and food pipe is called trachea.
Answer:
(a) Wind pipe is present in front of food pipe.

Question 3.
Which type of respiration includes inhalation and exhalation?
(a) Internal respiration
(b) External respiration
(c) Cellular respiration
(d) None of the above
Answer:
(b) External respiration

Question 4.
How many molecules of ATP are produced from one molecule of glucose ?
(a) 26
(b) 36
(c) 38
(d) 40
Answer:
(c) 38

Question 5.
Where is sound box located in the body?
(a) At the beginning of the wind pipe.
(b) At the beginning of the food pipe.
(c) At the end of the wind pipe.
(d) At the end of the food pipe.
Answer:
(a) At the beginning of the wind pipe.

II. Structure of heart:

Question 1.
What is the location of a bicuspid valve in human heart?
(a) Between right and left ventricle.
(b) Between left and right atrium.
(c) Between left atrium and left ventricle.
(d) Between right atrium and right ventricle.
Answer:
(c) Between left atrium and left ventricle.

Question 2.
Which blood vessels bring deoxygenated blood to the right atrium?
(a) Superior and inferior vena cava
(b) Pulmonary veins
(c) Pulmonary artery
(d) Systemic aorta
Answer:
(a) Superior and inferior vena cava

Question 3.
Which artery carries deoxygenated blood and which vein carries the oxygenated blood respectively?
(a) Dorsal aorta and inferior vena cava respectively.
(b) Pulmonary vein and pulmonary artery respectively
(c) Pulmonary artery and pulmonary vein respectively
(d) Superior vena cava and inferior vena cava respectively.
Answer:
(c) Pulmonary artery and pulmonary vein respectively

Question 4.
Under which of the following condition will rate of heartbeat be faster?
(a) Sleeping
(b) Resting
(c) Running
(d) Sitting
Answer:
(c) Running

Question 5.
Which chambers of the heart are called receiving chamber?
(a) Both atria
(b) Right ventricle
(c) Left ventricle
(d) Only left atria
Answer:
(a) Both atria

8th Std Science Questions And Answers:

Current Electricity and Magnetism Class 8 Science Chapter 4 Questions And Answers Maharashtra Board

February 6, 2025February 5, 2025 by Bhagya

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 4 Current Electricity and Magnetism Notes, Textbook Exercise Important Questions and Answers.

Std 8 Science Chapter 4 Current Electricity and Magnetism Question Answer Maharashtra Board

Class 8 Science Chapter 4 Current Electricity and Magnetism Question Answer Maharashtra Board

1. Write proper words from the following group of words in the blanks and rewrite the completed sentences:
(magnetism, 4.5V, 3.0V, gravitational attraction, potential difference, potential, higher, lower, 0V)

Question a.
Water in the waterfall flows from a higher level to the lower level because of …………… .
Answer:
Water in the waterfall flows from a higher level to the lower level because of gravitational attraction.

Question b.
In an electric circuit, electrons flow from a point of potential to the point of ……….. potential.
Answer:
In an electric circuit, electrons flow from a point of lower potential to the point of higher potential.

Question c.
The difference between the electrostatic potential of the positive end and the negative end of an electric cell is the …………. of the cell.
Answer:
The difference between the electrostatic potential of the positive end and the negative end of an electric cell is the potential difference of the cell.

Question d.
Three electric cells of potential difference 1.5 V each have been connected as a battery. The potential difference of the battery will be ……………… V.
Answer:
Three electric cells of potential difference 1.5 V each have been connected as a battery. The potential difference of the battery will be 4.5 V.

Question e.
An electric current flowing in a wire creates ………………… around the wire.
Answer:
An electric current flowing in a wire creates magnetism around the wire.

2. A battery is to be formed by joining 3 dry cells with connecting wires. Show how you will connect the wires by drawing a diagram.

Question a.
A battery is to be formed by joining 3 dry cells with connecting wires. Show how you will connect the wires by drawing a diagram.
Answer:

3. In an electric circuit, a battery and a bulb have been connected and the battery consists of two cells of equal potential difference. If the bulb is not glowing, then which tests will you perform in order to find out the reason for the bulb not glowing?

Question a.
In an electric circuit, a battery and a bulb have been connected and the battery consists of two cells of equal potential difference. If the bulb is not glowing, then which tests will you perform in order to find out the reason for the bulb not glowing?
Answer:
If you can see the filament of the bulb, check whether it is intact or broken. Check whether the cells are connected in a proper manner:

Or in a wrong way:
If they are connected in a wrong way as shown above, the total potential difference will be 2V + (-2V) = zero.
Figures for reference:

4. Electric cells having potential difference 2V each have been connected in the form of a battery. What will be the total potential difference of the battery in both cases?

Question a.
Electric cells having potential difference 2V each have been connected in the form of a battery. What will be the total potential difference of the battery in both cases?

Answer:
(i) 6V
(ii) 8V.
[Note: In (i), three cells are connected in series.
∴ Total potential difference = 2V + 2V + 2V = 6V.
In (ii), four cells are connected in series.
∴ Total potential difference = 2V + 2V + 2V + 2V
= 8 V]

5. Describe the construction, working and usefulness of a dry cell, with the help of a diagram.
Question a.
Describe the construction, working and usefulness of a dry cell, with the help of a diagram.
Answer:

Dry cell:
Take a lead dry cell and remove its outer coating. Inside you will find a whitish, metal layer. This is the zinc (Zn) metal layer. This is the negative terminal of the cell. Now, carefully break open this layer. There is another layer inside. An electrolyte is filled between these two layers.

The electrolyte contains negatively charged and positively charged ions. These are the carriers of electricity. The electrolyte is a wet pulp of zinc chloride (ZnCl₂) and ammonium chloride (NH₄Cl). There is a graphite rod at the centre of the cell. This is positive terminal of the cell. A paste of manganese dioxide (MnO₂) is filled outside the rod. Because of the chemical reactions of all these chemicals, electrical charge is produced on the two terminals (graphite rod and zinc layer) and an electric current flows in the circuit.

Due to the wet pulp used in this cell, the chemical reaction proceeds very slowly. Hence a large electric current cannot be obtained from this. Compared to the electric cells using liquids, the shelf life of dry cells is longer. Dry cells are very convenient to use as these can be held in any direction with respect to ground and can be used in mobile instruments such as radio sets, wall clocks and torches.

6. Describe the construction and working of an electric bell with the help of a diagram.

Question a.
Describe the construction and working of an electric bell with the help of a diagram.
Answer:
Figure shows the construction of an electric bell and also the electric circuit. The bell consists of an electromagnet, contact screw, iron strip, metal striker and metal gong. A coil of copper wire wound around an iron piece works as an electromagnet and an iron strip along with a striker is fitted near it. A contact screw touches the strip.

The circuit is closed with the key. The current flows in the circuit when the screw is in contact with the iron strip. The current – carrying coil becomes a magnet and attracts the iron strip towards it. As a result, the metal striker hits the metal gong producing sound. At the same time, the screw loses the contact with the strip. The circuit is now incomplete.

Hence, no current flows in the circuit. Therefore, the electromagnet loses its magnetism and the electric iron strip returns to its initial condition, making contact with the screw. As the circuit is now completed, the electromagnet attracts the iron strip and the striker strikes the gong producing sound.

The action repeats itself and the bell continues to ring till the circuit is broken by opening the key in the circuit.
The working of the electric bell is thus based on the magnetic effect of electric current.

Project:

Present all the activities that you performed in this chapter in Science exhibition.

Class 8 Science Chapter 4 Current Electricity and Magnetism Additional Important Questions and Answers

Rewrite the sentences after filling the blanks:

Question 1.
The SI unit of electric charge is the ……………… .
Answer:
The SI unit of electric charge is the coulomb.

Question 2.
The SI unit of electric current is the ……………… .
Answer:
The SI unit of electric current is the ampere.

Question 3.
The SI unit of electric potential is the ………………. .
Answer:
The SI unit of electric potential is the volt.

Question 4.
1 ampere = 1 coulomb per …………… .
Answer:
1 ampere = 1 coulomb per second.

Question 5.
When a glass rod is rubbed on a silk cloth, the glass rod acquires …………… charge.
Answer:
When a glass rod is rubbed on a silk cloth, the glass rod acquires positive charge.

Rewrite the following statements selecting the correct options:

Question 1.
The potential difference between the two electrodes of the lead-acid cell is nearly ………………. .
(a) 1 V
(b) 1.2 V
(c) 1.5 V
(d) 2 V
Answer:
(d) 2 V

Question 2.
The Ni-Cd cell delivers a potential difference of …………….. .
(a) 1 V
(b) 1.2 V
(c) 1.5 V
(d) 2 V
Answer:
(b) 1.2 V

Question 3.
…………….. is a scalar quantity.
(a) Force
(b) Acceleration
(c) Velocity
(d) Electric current
Answer:
(d) Electric current

Question 4.
The working of an electric bell is based on ………….. .
(a) the heating effect of electric current
(b) the chemical effect of electric current
(c) the magnetic effect of electric current
(d) the optical effect of electric current
Answer:
(c) the magnetic effect of electric current

Question 5.
The coulomb is the SI unit of electric ………….. .
(a) current
(b) resistance
(c) potential
(d) charge
Answer:
(d) charge

State whether the following statements are True or False:

Question 1.
The SI unit of electric potential is the ampere.
Answer:
False. (The SI unit of electric potential is the volt. OR The SI unit of electric current is the ampere.)

Question 2.
In the external circuit, the conventional current flows from the positive terminal of the cell to the negative terminal of the cell.
Answer:
True.

Question 3.
Very small current flows when lightning occurs.
Answer:
False. (A large current flows when lightning occurs.)

Question 4.
Sensation is felt by us due to a microscopically small current flowing to the brain.
Answer:
True.

Question 5.
In a car battery, a current is produced by the flow of both negatively and positively charged particles.
Answer:
True.

Identify the odd term:

Question 1.
Pressure exerted by a liquid, Electric current, Electric potential difference, Buoyant force.
Answer:
Buoyant force. It is a vector quantity. Others are scalar quantities.

Question 2.
Electric bulb, Electric heater, Electric bell, Electric iron.
Answer:
Electric bell. Its working is based on the magnetic effect of electric current. The working of other devices is based on the heating effect of electric current.

Answer the following questions in one sentence:

Question 1.
State the relation among the SI units of electric current, electric charge and time.
Answer:
1 ampere = 1 coulomb per second.

Question 2.
Name the positive terminal of the dry cell.
Answer:
The graphite rod at the centre is the positive terminal of the dry cell.

Question 3.
What constitutes an electric current in a metal?
Answer:
A continuous flow of electrons constitutes an electric current in a metal.

Question 4.
What is a battery?
Answer:
A group of two or more cells connected in series to obtain more potential difference is called a battery.

Question 5.
What is a solar cell?
Answer:
A solar cell is a device that converts solar energy into electrical energy.

Question 6.
State one characteristic of the Ni-Cd cell.
Answer:
The Ni-Cd cell is rechargeable.

Question 7.
Give one example in which the magnetic effect of electric current is used.
Answer:
The working of an electric bell is based on the magnetic effect of electric current.

Answer the following questions:

Question 1.
When do we get current electricity?
Answer:
We get current electricity when charged particles such as electrons, positive ions and negative ions are made to flow in a conductor by applying electric force.

Question 2.
Explain the concept of electrostatic potential (electric potential).
Answer:
A liquid flows from a higher level to a lower level. Heat flows from a body at a higher temperature to a body at a lower temperature. Also when different parts of a body are at different temperatures, heat flows from the part at a higher temperature to the part at a lower temperature.

Similarly, a positive charge (free to move) flows from a point at a higher electric level to a point at a lower electric level and a negative charge (free to move) flows from a point at a lower electric level to a point at a higher electric level. The electric level deciding the direction of flow of electric charge is called electrostatic potential (electric potential).

Question 3.
What is the SI unit of electric potential?
Answer:
The SI unit of electric potential is the volt (V).
[Note : This unit is named in honour of Alessandro Volta (1745-1827), Italian physicist, the inventor of the electric battery.]

Question 4.
What is potential difference?
Answer:
Potential difference is the difference
between the potentials at two points. It is similar to the height of a waterfall or the temperature difference between a hot body and a cold body. Potential difference is expressed in volt.

Try this:

Take connecting copper wires and connect the ‘circuit’ as shown in Fig.(a). No current is seen to flow in the bulb. Now connect in the same ‘circuit’ a 1.5 V dry cell available in the market as shown in Fig.(b). Now it will be realized from glowing of the bulb that a current is flowing in the circuit. Electrons in the wire flow due to the potential difference between the two ends

In Fig.(a), there is no current as ) there is no potential difference in the absence of any cell. Current starts flowing in the circuit as soon as the potential difference is applied. The unit of potential difference in SI system is the volt (V). We will learn about it in the next standard.

Question 5.
What is electric circuit or electrical circuit?
Answer:
A continuous path consisting of conducting wires, a switch or a plug key and other resistances (for example, resistance of an electric bulb) between the terminals of a cell (or a battery) along which an electric current flows is called an electric circuit.

Question 6.
What is electric current?
Answer:
Electric current is the electric charge flowing through a conductor, such as a metal wire, per unit time.

Question 7.
What is one ampere?
Answer:
If one coulomb of charge is passing through any cross section of a conductor in one second, the amount of current flowing through it is called one ampere.
[Note: 1 ampere = 1 coulomb per second OR 1A = 1 C/s. The coulomb is named in honour of Charles Augustin de Coulomb (1736 – 1806), French physicist. The ampere is named in honour of Andre Ampere (1175 – 1836), French physicist and mathematician.]

Think about it:

Question a.
How can we measure water flow emerging from a pipe? We can find it from the amount of water (litres) coming out in a specific time period. How then is the electric current measured?
Answer:
Electric current, I = Q/t. In principle, if we can measure the quantity of charge (Q) flowing through a cross section of a conductor in time t, we can determine the current (i) using this formula (for a steady current). In practice, this is not done. Usually, electric current is measured using the magnetic effect of electric current. One can also use the heating effect and chemical effect of electric current for measurement of electric current.

Question 8.
What is an electric cell? What is its main function?
Answer:
An electric cell is a general device used to produce a uniform flow of charges in a circuit. Its main function is to maintain a constant potential difference between its two terminals.

Question 9.
Name ten devices in which electric cells are used.
Answer:
Electric cells are used in radio sets, wall clocks, wrist watches, torches, toys, mobile phones, cars, invertors, remote controls, ships, submarines, satellites, etc.

Question 10.
Draw a neat labelled diagram to show the design of the lead-acid cell and explain its principle of working.
Answer:
The lead-acid cell contains two electrodes, Pb and PbO₂, dipped in dilute H₂SO₄. Chemical reaction between the substances in the cell produces electric charges on the electrodes. PbO₂ carries a positive charge and Pb carries a negative charge. The potential difference between the electrodes is nearly 2V.

If a load, such as a bulb, is connected externally between the two electrodes, an electric current flows through it. It can deliver a large current. This cell can be recharged after getting electrically discharged.

Question 11.
State applications of the lead-acid cell.
Answer:
Lead-acid cells are connected in series to obtain higher potential difference. The lead-acid battery is used in cars, trucks, motorcycles and uninterrupted power supplies (UPS).

Question 12.
What is the potential difference delivered by the Ni-Cd cell?
Answer:
The potential difference delivered by the Ni-Cd cell is (about) 1.2 V.
[Note: In this cell, nickel oxide is the positive electrode and cadmium is the negative electrode. It is often used as a dry cell and it can be recharged. These cells are used in some portable machines that run on electricity like a drilling machine or a gardening tool.]

Question 13.
Draw a neat labelled diagram of a simple electric circuit containing a cell, an electric bulb and a plug key. What happens when the key is (i) open (ii) closed?
Answer:

(i) When the key is open, there is no current in the circuit. Hence, the bulb does not glow.
(ii) When the key is closed, a current flows in the circuit. Hence, the bulb glows.

Figure for reference:
Here, six cells can be connected in series to obtain more potential difference.

Research:
Lithium ion cells are used in modern equipment for example, a smart phone, laptop, etc. These cells can be recharged. More electrical energy can be stored in these cells as compared to that in Ni-Cd cells.

Question 14.
See Fig. What is the potential difference between A and B if each cell delivers a potential difference of 2V?

Answer:
Potential difference between A and B
= 2V + 2V + (-2V) + 2V = 4V.

Use your brain power!

Question a.
You must have seen the car battery available in the market. It is called a battery and not a cell. Why?
Answer:
In a car battery, a number of cells are connected in series to obtain more potential difference.

Here, two identical cells are connected in parallel. The potential difference between A and B is 2V. This arrangement can be used for a longer time compared to a single cell.

Series and parallel arrangement for higher potential difference and longer life.
Here, the potential difference between A and B is 8V.

Try this:

Magnetic effects of electric current :
Activity 1 :
Take the inside tray of a used up matchbox. Place a small magnetic needle inside the tray. Now take a long connecting wire and wind it around the tray. Complete the electric circuit by connecting in it, this wire, electric cell, plug key and a bulb Figure.

Mark the position of the magnetic needle. Take a bar magnet near to the magnetic needle.
1. What do you observe? Keep looking at the needle and close the plug key. The bulb will light up, and you will realize that the current has started flowing.
2. Does the magnetic needle change its position? Now open the plug key.
3. Does the magnetic needle come back to the original position?
4. What will you conclude from this experiment?
You know that a magnetic needle is indeed a magnet. You have seen that the magnetic needle changes its direction when a bar magnet is taken near the magnetic needle. Also, you have observed that the magnetic needle changes its direction when a current starts flowing in the circuit. This means that magnetic field is created when an electric current flows in a wire. Hans Christian Oersted made this observation first. Briefly we can say that when an electric current passes through a wire, a magnetic field is produced around that wire.
Answer:

The magnetic needle is deflected.
Yes.
Yes.
The electric current produces a magnetic field around a current-carrying conductor.

Activity 2 :
Take a metre long flexible copper wire having resistive coating and wind it tightly on a long iron screw. Connect the two ends of the wire in a circuit as shown in the Figure. Also connect an electric cell and a plug key in the circuit. Keep 2-4 iron pins/small nails near the screw. Now start the current in the circuit by plugging the key. It will be noticed that the pins/nails have stuck to the tip of the screw. Will the pins/nails continue to stick when the plug key is opened?

Answer:
No.
When the electric current flows in the wire, magnetism is produced in the coil around the screw and because of that the screw also attains magnetism. As soon as the current is stopped, this magnetism vanishes. The system of the coil and the screw is called an electromagnet. You have seen various uses of the electromagnet in the sixth standard. Electromagnets are used to produce a strong magnetic field useful in scientific research.

Question 15.
What is an electromagnet? State ! its applications.
Answer:
If a coil is wound around an iron screw (or an iron rod) and a current is passed through the coil with a cell (or a battery), the screw behaves as a magnet as long as there is current in the coil. The i system of the coil and the screw is called an electromagnet. It is an example of magnetic effect of electric current.
Applications: Electric bell, cranes for moving heavy loads from one place to another, toys that run on electric cells.

Question 16.
How can the strength of an electromagnet be increased?
Answer:
The strength of an electromagnet can be increased by increasing the current producing the magnetic field.

Question 17.
What is the use of the elastic iron strip in the electric bell?
Answer:
Due to the elastic iron strip, the making and breaking of the circuit occur alternately and the bell continues to ring as long as the key in the circuit is closed.

Question 18.
What will happen if the elastic iron strip in the electric bell loses its flexibility?
Answer:
When the circuit breaks and the electromagnet loses its magnetism, the strip, due to loss of flexibility, will not return to its normal position of contact with the screw. Hence, the circuit will not be completed and the bell will not ring.

8th Std Science Questions And Answers: