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Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 11 Work and Energy Notes, Textbook Exercise Important Questions and Answers.

Std 6 Science Chapter 11 Work and Energy Question Answer Maharashtra Board

Class 6 Science Chapter 11 Work and Energy Question Answer Maharashtra Board

1. Fill in each blank with the appropriate term from the brackets.

Question a.
A bucketful of water is to be drawn from a well ………. will be done when a ………… is applied to do this, because there will be an ……………. of water.
(displacement, workforce)
Answer:
work, force, displacement

Question b.
If a ball is dropped on the sloping roof of a house, it acquires ……………. and falls on the ground. That is transformation of ………… energy into ……….. energy takes place.
(kinetic, potential, motion)
Answer:
motion, kinetic, potential

Question c.
You might have seen some beautiful fireworks during Diwali. It is an example of transformation of ……….. energy into ………………. energy.
(light, atom, chemical, solar)
Answer:
chemical, light

Question d.
The solar cooker is an application of the ………… energy of the sun, while solar cells, solar lamps are applications of the ………….. energy of the sun.
(light, chemical, heat)
Answer:
heat, light

Question e.
One labourer carried four pans of road metal through a distance of 100 metres. If he carries two pans of road metal through a 200 metre distance …………. work will be done.
(equal, more, less)
Answer:
equal

Question f.
The capacity that an object has for doing work is called ………… .
(energy, displacement, force)
Answer:
energy

2. Match the pairs.

Question a.

Column ‘A’	Column ‘B’
1. Rolling object	a. Heat energy
2. Food	b. Atomic energy
3. Stretched bow	c. Kinetic energy
4. Sunlight	d. Potential energy
5. Uranium	e. Chemical energy

Answer:

Column ‘A’	Column ‘B’
1. Rolling object	c. Kinetic energy
2. Food	e. Chemical energy
3. Stretched bow	d. Potential energy
4. Sunlight	a. Heat energy
5. Uranium	b. Atomic energy

3. Can you tell?

Question a.
When can we say that displacement has taken place?
Answer:
When the position of an object changes, we say that the object is displaced.

Question b.
What are the various forms of energy?
Answer:
Various forms of energy are: mechanical energy, heat energy, light energy, sound energy, chemical energy and electrical energy.

Question c.
Describe the natural chain of transformation of energy.
Answer:

1. In the course of water cycle, water evaporates due to the heat of the sun.
2. This water vapour forms clouds that give rain.
3. Rainwater flows into rivers and is stored in reservoirs or dams.
4. This stored water at a height has potential energy.
5. As the water falls down, this is transformed into kinetic energy.
6. When the water falls on the turbine, its kinetic energy is transferred to turbine.
7. The turbine rotates producing electrical energy.

Question d.
What should be taken into account for measuring work?
Answer:
For measuring work both force and displacement must be taken into account.

Question e.
Why should we save energy?
Answer:
Due to increasing population and increasing use of energy resources, there is a danger that limited reserves of coal, petrol, etc. will get exhausted. Hence, we should save energy for future generation.

Question f.
What is ‘green energy’?
Answer:
The energy resources which do not produce smoke and carbon gases such as carbon dioxide or carbon monoxide are called ‘green energy resources’. Energy from them is called green energy.

Question g.
What are the non-conventional energy resources?
Answer:
The resources that:

1. have not been used traditionally.
2. are inexhaustible and continuous.
3. That can be used in various forms again and again are called non-conventional energy resources.
4. e.g.: solar energy, wind energy, tidal energy, hydal power.

Question h.
Which forms of energy from the sun is used in solar energy devices?
Answer:

1. Heat energy from the sun is used in solar cookers, solar water heaters, solar driers.
2. Light energy from the sun is used in solar cells, solar panels.
3. Solar electric plants have the capacity to produce electricity on large scale.

Question i.
Why should we maximize the use of non- ntional energy sources?
Answer:

1. Due to increase in population there is increasing use of conventional sources like petrol, coal, etc. Their reserves are limited and they may get exhausted.
2. Hence, it will be better to use non- conventional sources of energy to save conventional resources for future.

4. Who is the odd-one-out?

Class 6 Science Chapter 11 Work And Energy Question 1.
Diesel, crude oil, natural gas, wind.
Answer:
wind

Work And Energy Class 6 Maharashtra Board Question 2.
A running car, hauling a log, a book kept on a table, picking up the school bag.
Answer:
A book kept on table.

Work And Energy Class 6 Question 3.
Sunlight, wind, wave, petrol.
Answer:
Petrol.

11 Work And Energy Class 6 Question 4.
Leaving the fan on in a vacant room, leaving the TV on while working, using A.C during winter, putting off the light when going out.
Answer:
putting off the light when going out.

5. Find out the types of energy from the following puzzle.

Question a.
Find out the types of energy from the following puzzle.

Answer:
Potential, Kinetic, Solar, Wind, Sound, Light, Heat

Activity:

Work And Energy Exercise Class 6 Question 1.
How can you save energy at home and in school? Discuss this with your friends and list all such measures. Put them into practice.

Work And Energy Class 6 Questions Answers Question 2.
Find out about energy saving devices available in the market.

Class 6 Science Chapter 11 Work and Energy Important Questions and Answers

Fill in the blanks with suitable words.

Work And Energy Class 6 Exercise Question 1.
Falling water possesses ………………… energy.
(potential, kinetic, chemical)
Answer:
kinetic

Work And Energy Class 6 Questions And Answers Question 2.
Heat is measured in unit called ……………….. .
(kilometres, kilogram, calorie)
Answer:
calorie

Class 6 Science Chapter 11 Question 3.
Plant stores the food in the form of ……………….. energy.
(mechanical, light, chemical)
Answer:
chemical

11. Work And Energy Class 6 Question 4.
We should use ……………….. energy resources with care.
(conventional, non-conventional, both)
Answer:
conventional

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
1. Solar energy	a. Waves
2. Tidal energy	b. Home cooking
3. Natural gas	c. Car
4. Petrol	d. Solar water heater

Answer:

Column ‘A’	Column ‘B’
1. Solar energy	d. Solar water heater
2. Tidal energy	a. Waves
3. Natural gas	b. Home cooking
4. Petrol	c. Car

Can you tell?

6th Science Work And Energy Question 1.
Water in dams or reservoirs shows potential energy.
Answer:
Rainwater flows into river and is stored in reservoirs on dams. These are at height and therefore, their water has potential energy.

Class 6 Science Chapter 11 Question Answer Question 2.
The sun is the most important source of all energy.
Answer:
All forms of energy are utilizing indirectly solar energy in all transformation of energy. Therefore, the sun is the most important source of all energy.

Question 3.
What is tidal energy?
Answer:
A wall is constructed at a narrow region of a creek. Due to waves generated by high and low tides, the turbine of the generator fitted in the wall starts rotating and electricity is generated.

Use your brain power!

Question 1.
Why do you get hungry after physical exercise?
Answer:

1. When we do physical exercise we use the energy stored in the body.
2. To replenish this energy, we have to eat. Hence we feel hungry.

Question 2.
From where does our body get energy.
Answer:
Our body gets energy from the food we eat.

Question 3.
Why do we get tired?
Answer:
When we do any work, we use the energy. If this energy level becomes very low, then we feel tired.

Question 4.
What is the unit of work and energy?
Answer:
The unit of work and energy in SI (System International) is ‘Joule’.

Question 5.
If no displacement occurs on applying a force, what does it indicate?
Answer:
If no displacement occurs, then no work is said to be performed.

Can you tell?

Question 1.
In the game of marbles, from where does one marble get energy to set another marble in motion?
Answer:
When we apply physical force to the fast marble, it gains some force and when it strikes the second marble, energy in the form of force is transferred to the second marble and this force sets the second marble in motion.

Question 2.
While playing carrom from where does the striker gets the energy to make the pieces move?
Answer:
When we strike the striker, the force exerted by our muscles is transferred to the striker. When the striker strikes the coin, this energy is transferred to the coin which may help to pocket the coin.

Question 3.
What will happen as result of the action in the picture?

Question i.
The rubber band is released after streaching it.
Answer:
It comes back to its orriginal position.

Question ii.
A stone is held in the rubber of a catapult, the rubber is stretched and released.
Answer:
Stone gets thrown to a distance and rubber band cones back to its original position.

Let’s try this.

Question 1.
If we hold a convex lens over a sheet of paper in sunlight such that there is tiny spot of light on the paper for a while. What happens? Why?
Answer:

1. If a convex lens is held over a paper in sunlight such that there is a tiny spot of light on the paper for a while the paper bums.
2. This is due to the heat energy of the sun concentrated at a point due to the convex lens.

Question 2.
How does a picture appear on the screen of a TV?
Answer:
When a TV is switched on, the electrical energy is converted into light and sound energy. Hence, a picture appears on TV.

Question 3.
In which form is energy stored in plant food?
Answer:
Energy stored in plant food is in the form of chemical energy.

Question 4.
How is energy obtained from cooking gas?
Answer:
Energy obtained from cooking gas is heat energy which is obtained by conversion of chemical energy.

Question 5.
Why is Energy not visible to us?
Answer:
Energy is the capacity to do work. Energy is converted from one form to another in the form of work being done. Hence it is not visible to us.

How are we different from each other?

Question 1.
Potential energy and Kinetic energy
Answer:

Potential energy	Kinetic energy
1. Energy stored in an object due to its position is called potential energy.	1. Energy possessed by a body due to its motion is called kinetic energy.
2. No work is performed.	2. Work is performed.

Question 2.
Work and energy
Answer:

Work	Energy
1. When an object is displaced by applying force on it, work is said to be done.	1. Energy is the capacity to do work.
2. Work is done as a result of using energy.	2. Energy is the cause for work to be done.

Question 3.
Conventional and Non-conventional energy sources
Answer:

Conventional source of energy	Non-Conventional source of energy
1. Man has been using these energy resources for centuries.	1. These resources have not been used traditionally.

Classify as directed:

Question 1.
Into kinetic and potential energy
Waterfalls, water in a reservoir, a stretched spring, a boy running in a race.
Answer:

• Potential – water in a reservoir, a stretched spring.
• Kinetic – waterfalls, a boy running in a race.

Question 2.
Into conventional and non-conventional energy sources.
Tidal energy, diesel, cooking gas, coal, hydropower, solar energy.
Answer:

• Conventional energy sources – diesel, cooking gas, coal.
• Non-conventional energy sources – tidal energy, hydropower, solar energy.

Question 3.
Into different forms of energy

1. rubber band is released
2. cooking food
3. switching on fan
4. a battery
5. radio
6. TV

Answer:

1. Mechanical energy
2. Heat energy
3. Mechanical energy, electrical energy
4. Chemical energy
5. Sound energy
6. Light and sound energy

Define:

Question 1.
Work
Answer:
When an object is displaced by applying a force on it, work is said to be done.

Question 2.
Energy
Answer:
Energy is the capacity to do work.

Question 3.
Chemical energy
Answer:
The energy obtained through chemical action is called chemical energy.

Question 4.
Potential energy
Answer:
The energy which is stored in an object due to a specific state or position of that object is called potential energy.

Question 5.
Kinetic energy
Answer:
The energy obtained by the virtue of its motion is called kinetic energy.

Question 6.
Solar energy
Answer:
The enormous and continuous energy obtained from the sun is called solar energy. Solar energy is at the root of all energy available on earth.

Question 7.
Conventional energy resources: (non-renewable energy sources)
Answer:
The energy sources which man has been using for centuries and that cannot be replenished are called conventional energy sources.

Question 8.
Renewable energy sources: (non – conventional energy sources)
Answer:
The resources that have not been used traditionally and that are inexhaustible, continuous and can be used in various forms again and again are called renewable energy sources.

Explain – why?

Question 1.
Energy is not visible to us.
Answer:
There is energy in every substance in the universe. It is present in non-living as well as living things. But still we can only feel the energy when some work is done, e.g. When wind blows, we can feel the coolness in air. When we switch on the light in a dark room, we can see things due to light energy.

Question 2.
Save energy, (use alternative energy sources)
Answer:

1. Due to increasing population, there is increasing usage of energy resources.
2. There is a danger that limited reserves of conventional resources like diesel, crude oil, may get exhausted.
3. We should save energy so that future availability is ensured.
4. It will be better to use alternative and supplementary energy sources.

Question 3.
Methods of saving energy.
Answer:

1. Saving energy is as good as generating energy.
2. There are several ways of saving energy such as putting off lamps when not needed.
3. Making maximum use of sunlight.
4. Saving energy and energy resources is absolutely necessary. Otherwise, we will have to face the serious calamity like global warming.

Question 4.
State the energy conversions in following cases.

1. Solar water heater
2. Solar cell
3. Fission of uranium, thorium
4. Switch on mixer
5. Switch on lamp
6. Switch on TV
7. Switch on radio
8. Ram plays tabla
9. Ravi plays shehnai
10. You switch on the torch
11. Your mother lights the gas stove to cook
12. Dinesh is bursting crackers during Diwali

Answer:

1. Solar energy to heat energy
2. Solar energy to electrical energy
3. Atomic energy to heat energy and then to electrical energy
4. Electrical energy to mechanical energy
5. Electrical energy to light energy
6. Electrical energy to light energy and sound energy
7. Electrical energy to sound energy,
8. Mechanical energy to sound energy
9. Wind energy to sound energy
10. Chemical energy to light energy
11. Chemical energy to heat energy
12. Chemical energy to heat, light and sound energy

Observe the figure below and answer the question given.

Question i.
In the above activity, which are the different forces acting on the box?
Answer:
In the above activity, muscular force, frictional force and gravitational force act on the box.

Question ii.
Is displacement possible without force?
Answer:
No, force has to be applied in order to displace the box.

Question iii.
If force is applied to both the boxes is same, which box will be displaced more?
Answer:
If force applied to both the boxes is same, then empty box will be displaced more than box with books.

Question iv.
If me e books are added to box, and same force is applied, will the displacement be more or less?
Answer:
If the same force is applied for a heavier load then the displacement will be less.

Question v.a.
If a force is applied with both the hands on a wall, will there be a displacement?
Answer:
Whatever be the amount of force applied, the wall will not be displaced.

Question b.
If no displacement occurs on applying as force, what does it indicate?
Answer:
If no displacement occurs, then no work is said to be performed.

6th Std Science Questions And Answers:

• Work and Energy Class 6 Questions And Answers
• Simple Machines Class 6 Questions And Answers
• Sound Class 6 Questions And Answers
• Light and the Formation of Shadows Class 6 Questions And Answers
• Fun with Magnets Class 6 Questions And Answers
• The Universe Class 6 Questions And Answers

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 17 Effects of Light Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 17 Effects of Light Question Answer Maharashtra Board

Class 7 Science Chapter 17 Effects of Light Question Answer Maharashtra Board

1. Fill in the blanks.

Question a.
When the beams from the headlights of a car fall on an object in the night, the shadows – called ………. and ………… . can be seen.
Answer:
umbra, penumbra

Question b.
During a lunar eclipse the shadow of the …………. falls on the ………. .
Answer:
earth, moon

Question c.
During a solar eclipse the shadow of the ………. falls on the ………… .
Answer:
moon, earth

Question d.
Various shades of colour are seen in the sky at sunrise and sunset due to ……….. .
Answer:
scattering of light

2. Give reasons.

Question a.
Space beyond the earth’s atmosphere appears dark.
Answer:

1. Space beyond the earth’s atmosphere does have some gas and cosmic dust but there is not any atmosphere.
2. As there are no particles to scatter the sunlight, the space appears black.

Question b.
We are able to read while sitting in the shade.
Answer:

1. We are able to read because the sun light which falls on the book is scattered and reaches our eyes.
2. While sitting in the shade our eyes adjust to the environment and to amount of light available. That is how we are able to read.

Question c.
We should not observe the solar eclipse with naked eyes.
Answer:

1. During a solar eclipse ultra-violet rays which are harmful to us reach the earth and may lead to eclipse blindness or retinal bums and cataracts.
2. In order to protect our eyes a solar eclipse should never be watched with the naked eye.
3. A special type of goggles should be used for this.

3. Give some examples of scattering of light that we come across in day to day life.

Question a.
Give some examples of scattering of light that we come across in day to day life.
Answer:

1. The formation of rainbow, shift in position of stars, increased day time, mirage, inverted image, glittering of diamond, the working of lens and prism, bending of pen in water are examples of scattering of light.
2. The blue colour of the sky is due to the scattering of sunlight by the molecules of air.
3. During sunrise and sunset, sunlight has to travel greater distance, so shorter wavelength gets scattered off and removed and only orange and red with longer wavelengths reach us.
4. So during sunrise and sunset, sky appears fed and orange.

4. Why is the shadow of a bird flying high not seen on the earth?

Question a.
Why is the shadow of a bird flying high not seen on the earth?
Answer:

1. Birds flying high in the sky do cast their shadow but because they are shading an area that is very tiny the shadow is not visible.
2. The higher the bird flies, the smaller the shadow it casts.
3. Also when the bird flies high, the dark part of the shadow that is called Umbra does not reach the ground so we do not see its shadow.

5. Why is a penumbra not obtained from a point source?

Question a.
Why is a penumbra not obtained from a point source?
Answer:

1. The umbra, penumbra are the distinct parts of a shadow, created by any light source after striking on an opaque object.
2. For a point source, only the umbra is cast sharp dark shadow and not penumbra, because all the light of the point source will be blocked by any shadowing object.
3. Whereas penumbra forms only when some of the light from the source gets blocked by the shadowing object and not all of it does.

6. Answer the following questions in your own words.

Question a.
What is meant by scattering of light?
Answer:

1. Scattering of light is the deviation of light rays from its straight path.
2. As light propagates through the atmosphere, it travels in a straight path until it is obstructed by bits of dust or gas molecules in the atmosphere
3. The process in which light gets deflected by the particles in the medium through which the light passes is called scattering, e.g. The blue colour of the sky is due to the scattering of sunlight by the molecules of air.

Question b.
Does the shadow really vanish in the zero shadow condition?
Answer:
1. Yes, the day on which the sun reaches exactly overhead, at noon, shadow completely disappears.
‘This event can be seen in the region between the Tropic of Cancer (23.5°N) and Tropic of Capricorn (23.5°S).
2. The shadow diminishes and eventually disappears for a while only to reappear later.

Question c.
Will the laser beam be seen if it passes through a glass box which contains a lighted incense stick?
Answer:
Yes, it will be seen.

7. Discuss and write:

Question a.
Write a science based paragraph on ‘What if the sun did not rise’?
Answer:

1. The sun is a star and the centre of our solar system. Everything in our solar system revolves around the sun.
2. If the sun were to suddenly disappear, Earth and the other planets would retain their forward motion, effectively flying off into outer space in a straight line.
3. If the Sun didn’t rise means the Earth’s rotation had come to a screeching halt.
4. Sunrise and sunset are a result of the earth’s rotation so we will not get to see sunrise or sunset. Earth’s spinning generates the magnetic field at the core and it is saving us from harmful rays from the sun.
5. Without sun it would be very dark. No sun means no plants and no animals. Of course, without sun none of us would even exist.
6. Moon will disappear, because the moon dose not produce light. We only see the moon because sunlight is reflected by the moon.
7. Without the sun’s warmth, Earth would quickly become a much colder place. Life would be difficult, oceans will freeze.
8. Without sun rays, all photosynthesis on earth would stop. All plants would die.
9. All animals that rely on plants for food, including humans would die.

Question b.
What efforts will you make to remove the misconceptions about eclipses?
Answer:
Solar, lunar eclipse have been traditionally observed as an ominous sign and therefore superstitions are prevalent in association with these natural phenomena.
1. All these misconceptions should be removed by explaining scientifically the process of eclipse how it happens: (a) Explain with the help of diagram and models of sun, moon and earth, (b) Explain how special glasses which will protect us from UV rays, and excess heat can be used to observe eclipses safely.
2. Also inform that eclipses are natural phenomena and can be predicted in advance.

Question c.
Various eclipses and the conditions during that period.
Answer:
There are two eclipses:

1. Solar eclipse
2. Lunar eclipse

1. Solar eclipse:
There are two types of Solar eclipse, (a) Total solar eclipse (b) Partial solar eclipse

a. Total solar eclipse: In total solar eclipse, the moon is between the sun and the earth and the moon shadow covers the sun disc fully by perfect alignment. The part of the earth that lies in the umbra of the moon experiences total solar eclipse.

b. Partial solar eclipse: In partial solar eclipse, the moon is between the sun and the earth arid the moon shadow does not cover the sun disc fully, because of imperfect alignment. The part of the earth that lies in the penumbra of the moon experiences partial solar eclipse.

c. The solar eclipse occur on a new moon day.
d. Solar eclipse last for few minutes.

2. Lunar eclipse:
There are two types of Lunar eclipse, (a) Total lunar eclipse (b) Partial lunar eclipse

a. Total lunar eclipse: In total lunar eclipse, the earth comes in between the sun and the moon and the earth’s shadow covers the moon’s surface fully because of perfect alignment.

b. Partial lunar eclipse: In partial lunar eclipse, the earth’s shadow does not cover the moon’s surface fully because of inperfect alignment. A small part of the moon’s surface is covered by umbra part of earth’s shadow.

c. The lunar eclipse occurs on a full moon night.
d. Lunar eclipse last for few hours.

8. Explain the difference:

Question a.
Point sources and Extended sources.
Answer:

Point sources	Extended sources
1. A source of radiation light that is concentrated at a point and considered as having no spatial extension.	1. An extended source is a source consisting of many point sources separated internally.
2. Shadow we get from a point source is dark called umbra.	2. Shadow we get from extended source of light is faint called penumbra and dark called umbra

Question b.
Umbra and Penumbra.
Answer:

Umbra	Penumbra
1. The umbra is a central core of darkness which tapers away.	1. The penumbra is an outer cone of partial shadow which diverges, instead of tapering.
2. Umbra is shadow formed from a point source of light.	2. It is the shadow formed from the extended source of light.
3. It is dark	3. It is faint
4. Umbra is the area of total shadow	4. Penumbra is the area of partial shadow.

Project:

Question a.
Obtain information about the special goggles used to watch a solar eclipse.

Class 7 Science Chapter 17 Effects of Light Important Questions and Answers

Fill in the blanks.

Question 1.
During solar eclipse ………….. comes between the sun and earth.
Answer:
moon

Question 2.
A solar eclipse is seen only on a ………….. day.
Answer:
new moon day

Question 3.
During lunar eclipse ……………. comes between the sun and the moon.
Answer:
earth

Question 4.
A lunar eclipse is seen only on a ………….. night.
Answer:
full moon

Question 5.
The day on which the sun reaches exactly overhead is called the …………… .
Answer:
zero shadow day

Question 6.
As seen from the earth, when a planet or star passes behind the moon, that state is called a ………….. .
Answer:
occultation

Give scientific reasons:

Question 1.
Sky appears blue to us.
Answer:

1. Sunlight is scattered by the molecules of gases like nitrogen, oxygen in the atmosphere.
2. The blue colour in the sunlight which is at shorter wavelength is scattered the most than other colours and therefore the sky appears blue.

Question 2.
Solar eclipse is either partial or total.
Answer:

1. When the moon comes in between the sun and the earth and the solar disc is corripletely covered by the moon, it is called total solar eclipse.
2. When the solar disc is not covered fully by the moon, it is partial solar eclipse.

Explain the difference:

Question 1.
Solar eclipse and Lunar eclipse.
Answer:

Solar eclipse	Lunar eclipse
1. When the moon comes between the sun and the earth, a shadow of the moon is cast on the earth and sun cannot be seen from the part in shadow. This is called a solar eclipse.	1. When the earth comes between the sun and the moon a shadow of the earth is cast on the moon and a part of the moon in covered this is called the lunar eclipse.
2. A solar eclipse is seen only on a new moon day.	2. A lunar eclipse is seen only on a full moon night.
3. A solar eclipse should never be watched with the naked eye. because ultra violate rays which are harmful to us reach the earth	3. A lunar eclipse can be seen with the naked eye.
4. It can be seen for a few minutes only.	4. It can be seen over a period of a few hours.

Explain diagrams:

Question 1.
Explain Solar eclipse with diagram.
Answer:
Solar eclipse:

1. During its revolution, when the moon comes between the sun and the earth, a shadow of the moon is cast on the earth and the sun cannot be seen from the part in the shadow. This is called a solar eclipse
2. A solar eclipse is seen only on a new moon day.
3. The solar eclipse may be either partial or total,
4. Sometimes the solar disc is completely covered by the moon. This is the total solar eclipse.
5. When the solar disc is not covered fully by the moon, we have a partial solar eclipse.
6. During a solar eclipse, ultra-violet rays which are harmful to us reach the earth.
7. A solar eclipse should never be watched with the naked eye.
8. A special type of goggles should be used for this purpose.
9. Solar eclipse can be seen for a few minutes only.

Question 2.
Explain Lunar eclipse with diagram
Answer:
Lunar eclipse:

1. When the earth comes between the sun and the moon a shadow of the earth is cast on the moon and a part of the moon is covered. This is called the lunar eclipse.
2. A lunar eclipse is seen only on a full moon night. If the whole moon comes in the shadow of the earth, it is a total lunar eclipse.
3. When the shadow of the earth is cast only on a part of the moon, it is a partial lunar eclipse. You can watch a lunar eclipse with the naked eye.
4. A lunar eclipse can be seen over a period of a few hours.

Question 3.
Write a short note on Zero Shadow Day.
Answer:

1. The day on which the sun reaches exactly overhead is called zero shadow day.
2. On this day, at noon, shadow completely disappears.
3. This event can be seen in the region between the Tropic of Cancer (23.5°N) and at tropic of Capricon (23.5°S).
4. The shadow diminishes and eventually disappears for a while only to reappear later
5. This phenomenon occurs twice every year Mumbai got to witness it on May 14, 2018 last year.

Question 4.
Explain the phenomenon of scattering of light with the help of an experiment.
Answer:

1. When the sun rises our surroundings appear illuminated. The entire sky appears bright.
2. This happens because of the dust and other tiny particles in the air. This is the scattering of sunlight by the tiny particles of the various constituents of air.
3. Had there been no atmosphere, the sky would have appeared dark during the day and of course, the sun would be directly seen.
4. This has been verified by observations from the rockets and satellites which go out of the earth’s atmosphere.

Apparatus: A table lamp with a 60 or 100 W milky bulb (LED will not do), thick black paper, sticking tape, a packing needle, 100/200 ml. glass beaker, milk or milk powder, dropper, spoon, etc.

Procedure: Cover the mouth of the lampshade properly with black paper, using sticking tape. Prick a hole of 1 to 2mm diameter in the center of the paper with the help of the packing needle.

1. Take clear water in the beaker. Light the bulb and place the beaker in contact with the hole.
2. Observe from the front and at an angle of 90°.
3. Now add 2-3 drops of milk to the water and stir. Observe again.
4. A few more drops of milk may have to be added to make the water turbid.
5. A blue tinge is seen when observed along the 90° angle. This is the scattered blue light.
6. Because the blue light is scattered, a red-yellow light is seen from the front, and the hole appears reddish.

Question 5.
Short note on Shadow.
Answer:

1. Shadow is a dark patch formed behind an opaque object when it is placed in the path of light.
2. A shadow is formed only when a light source, an opaque object and a screen are present, e.g. during a lunar eclipse we see a part of the earth’s shadow on the surface of the moon.
3. This happens when the earth, the sun, and the moon are in a straight line with the earth between sun and the moon.
4. Here the sun acts as the light source, the earth as the opaque object and moon as the screen.
5. Shadows are formed due the rectilinear propagation of light.
6. The size and the shape of the shadow depend on the position and orientation of the opaque object between the source of light and the screen.
7. If the distance of the object from the source is decreased, then the size of the shadow increases.
8. If the object is moved away from the source, then the size of the shadow decreases.
9. In older days shadows caused by objects placed in the sun were used to measure time. Such a device is called sun dial.

Use your brain power!

Answer the following questions:

Question 1.
Eclipses and transits which will occur recently.
Answer:

• January 6, 2019 – Partial solar eclipse
• January 21, 2019 – Total Lunar eclipse
• July 2, 2019 – Total solar eclipse
• July 16, 2019 – Partial Lunar eclipse
• December 26, 2019 – Annular solar eclipse.

Find Out:

Answer the following questions:

Question 1.
If a few drops of milk are added in the experiment given the reddish colour seen from the front becomes an intense red. However, if many more drops are added the reddish colour is not seen. Why is this so?
Answer:

1. As more and more milk is added, more particles of protein and fat scatter the light and the blue colour is scattered more and more than orange and red light and the beam appears blue from the sides.
2. If few drops of milk are added, along with blue colour, orange and yellow also are scattered and only the intense red is seen from the front.
3. But when many more drops are added, even the red colour is scattered and we do not see any colour from the front.

Question 2.
What is Occultation?
Answer:
As seen from the earth, when a planet or a star passes behind the moon, that state is called an Occultation.

Complete the Chart.

Question 1.

Answer:

• A – Solar B – Lunar
• C – Total Solar
• D – Partial Solar
• E – Total Lunar
• F – Partial Lunar
• G – Moon is not in a straight line between earth and sun
• H – It is in the penumbra region of the moon
• I – The earth comes in between the sun and moon and they are not in a straight line.

7th Std Science Questions And Answers:

• Cell Structure and Micro-organisms Class 7 Questions And Answers
• The Muscular System and Digestive System in Human Beings Class 7 Questions And Answers
• Changes – Physical and Chemical Class 7 Questions And Answers
• Elements, Compounds and Mixtures Class 7 Questions And Answers
• Materials We Use Class 7 Questions And Answers
• Natural Resources Class 7 Questions And Answers
• Effects of Light Class 7 Questions And Answers
• Sound: Production of Sound Class 7 Questions And Answers
• Properties of a Magnetic Field Class 7 Questions And Answers
• In the World of Stars Class 7 Questions And Answers

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 5 Food Safety Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 5 Food Safety Question Answer Maharashtra Board

Class 7 Science Chapter 5 Food Safety Question Answer Maharashtra Board

1. Complete the following statements by using the correct option from those given below.
(Irradiation, dehydration, pasteurization, natural, chemical)

Question a.
Drying the food grains from farms under the hot sun is called …………. .
Answer:
dehydration

Question b.
Materials like milk are instantly cooled after heating up to a certain high temperature. This method of food preservation is called ……….. .
Answer:
pasteurization

Question c.
Salt is a ……….. type of food preservative.
Answer:
natural

Question d.
Vinegar is a …………. type of food preservative.
Answer:
chemical

2. Answer the following questions in your own words. 

Question a.
How is milk pasteurised?
Answer:
Boil the milk at 80°C for 15 minutes and cool it quickly. This destroys the microbes present in the milk and it can remain for a longer duration. This process is called pasteurization of milk.

Question b.
Why should we not consume adulterated food materials?
Answer:
Different types of adulterants affect our health in different ways. Some adulterants cause abdominal discomfort or poisoning while some may affect the functioning of some organs if consumed over a long period of time or even cause cancer.

Question c.
What precautions do your parents take to keep foodstuffs safe?
Answer:
Our parents take following care to keep foodstuffs safe

1. Drying of grains.
2. Boiling of milk, soups and curries from time to time.
3. Refrigeration of vegetables, fruits, milk and cooked food.
4. Candying of jams.
5. Use natural preservatives like oil, spices, neem leaves, salt, etc.
6. Use chemical preservatives in sauces, ketchups, pickles, jams and squashes.

Question d.
How does food spoilage occur? Which are the various factors spoiling the food?
Answer:
Food spoilage is the process in which food deteriorates to the point in which it is not edible to humans or its quality of edibility becomes reduced.
Following are the factors for spoiling of food:

1. Bacteria causes food to spoil
2. Incorrect storage may spoil the food.
3. Infestation by pests.
4. Chemical reaction takes place in food and it gets spoiled.

Question e.
Which methods of food preservation would you use?
Answer:
I use following methods to preserve the food:

1. Freezing
2. Boiling
3. Salting of pickles
4. drying of grains
5. candying of jams.

3. What shall we do?

Question a.
There are vendors selling uncovered sweet-meats in open places in the market.
Answer:
We should tell them to sell the covered sweets because uncovered sweets are harmful to eat because it contains dust, dirt and germs. And buyers also should not purchase these uncovered sweets.

Question b.
A ‘pani-puriwala’ is serving the panipuri with dirty hands.
Answer:
We should tell him to wear gloves before serving panipuri because dirty hands contain dirt and germs which are harmful to us.

Question c.
We have purchased a large quantity of fruits and vegetables.
Answer:
We should keep them in refrigerator because in refrigerator, due to low temperature, fruits and vegetables do not spoil and biological and chemical reactions in fruits and vegetables are slowed down at low temperature.

Question d.
We need to protect foodstuffs from pests like rats, cockroaches, wall-lizards etc.
Answer:

1. If we do not protect foodstuffs from pests like rats, cockroaches, wall-lizards etc. then the food get spoiled by them and germs carried by them enters into the food.
2. If we eat this food then we may get food poisoning and we fall sick so we need to protect foodstuffs from pests like rat, cockroaches, wall lizards etc.

4. Find the odd-man-out. 

Question a.
Salt, vinegar, citric acid, sodium benzoate.
Answer:
Salt

Question b.
Lakhi dal, brick dust, metanyl yellow, turmeric powder.
Answer:
Turmeric powder

Question c.
Banana, apple, guava, almond.
Answer:
Almond

Question d.
Storing, freezing, settling, drying
Answer:
Storing

5. Complete the chart below.

Question a.

Answer:

Foodstuff	Adulterant
1. Turmeric powder	Metanil yellow
2. Black pepper	Dried papaya seeds
3. Rava	Iron filings
4. Honey	Sugar, water and jaggery

6. Explain why this happens and suggest possible remedies.

Question a.
Qualitative wastage of food.
Answer:
Qualitative wastage of food happens due to wrong methods of protecting food, excessive use of food preservatives, over-cooking, washing the vegetables after cutting them, mis¬handling of fruits like grapes and mangoes, miscalculation of the time required to transport food from producers to consumers are some of the reasons of qualitative wastage of food.
Possible remedies:

1. Avoid overcooking of food.
2. Store grains and other perishable foodstuffs like vegetables, fruits, milk etc. using proper methods.
3. Wash fruits and vegetables before cutting it.

Question b.
The cooked rice is underdone.
Answer:
Sometimes in a hurry if we cook the rice it is underdone.
Possible remedies: Use proper pressure cooker to cook the rice.

Question c.
The wheat that was bought is a bit moist.
Answer:
Sometimes due to sudden rain, wheat gets a bit moist. Possible remedies: Do not store the moist wheat, it gets spoiled due to fungus so first sundry it and then store in a clean and dry container to avoid microbial growth.

Question d.
The taste of yoghurt is too sour/slightly bitter.
Answer:
The taste of yoghurt is too sour/slightly bitter means it is spoiled. This happens if it is not kept in the refrigerator.
Possible remedies:- Always keep the yoghurt in refrigerator to avoid biological and chemical reactions in food materials.

Question e.
Cut fruits turned black.
Answer:
Fruit contains an enzyme called polyphenol oxidase or tyrosinase that reacts with oxygen. The oxidation reaction basically forms a sort of rust on the surface of fruits so it turns black.
Possible remedies:

1. Coat the fruits with sugar syrup
2. Add lemon juice on fruits.

7. Give reasons.

Question 1.
Food remains safe at 5° Celsius.
Answer:
Food remains safe at 5° Celsius because at 5°C, micro-organisms stop growing.

Question 2.
Nowadays, food is served in buffet style during large gatherings.
Answer:
Nowadays, food is served buffet style during large gatherings because due to buffet style quantitative wastage of food can be avoided, as people take only as much as they could eat.

Project:

Question 1.
Go to your kitchen und take notes about the food safety measures and the food wastage you see there.

Question 2.
In a science exhibition demonstrate the various methods of detecting food adulteration.

Class 7 Science Chapter 5 Food Safety Important Questions and Answers

Complete the following statements by using the correct option from those given below.
(Irradiation, dehydration, pasteurization, natural, chemical)

Question 1.
………………………. is celebrated as “World Food Day”.
Answer:
16th October

Question 2.
FSSAI means ………………………. .
Answer:
Food Safety and Standardization Authority of India

Question 3.
………………………. gas is filled in tight packets of potato wafers.
Answer:
Nitrogen

Question 4.
Common name of acetic acid is ……………………….
Answer:
Vinegar

Question 5.
………………………. is sprayed on the gunny bags containing food grains.
Answer:
Melathion

Question 6.
………………………. is used in smoking method.
Answer:
Aluminium phosphide

Question 7.
………………………. and ………………………. are emitted by radioactive isotopes in irradiation method.
Answer:
X – rays, gamma rays

Question 8.
In Maharashtra, irradiation plants have been installed at ………………………. for onions and potatoes and at for spices and condiments.
Answer:
Lasalgaon, Navi Mumbai

Question 9.
………………………. found the pasteurisation method.
Answer:
Louis Pasteur

Question 10.
………………………. adulterant is added to turmeric powder.
Answer:
Metanyl yellow

Question 11.
………………………. adulterant is added to red chilly powder.
Answer:
Brickdust

Question 12.
………………………. is used to make fruits more attractive.
Answer:
calcium carbide

Question 13.
………………………. and ………………………. harmful chemicals are mixed with cold drinks.
Answer:
carbonated soda, phosphoric acid

Question 14.
Shopkeepers change the of the ………………………. food packets fo avoid a financial loss.
Answer:
expiry date

Question 15.
Milk vendors add ………………………. to the milk to appear as higher fat content.
Answer:
urea

Question 16.
The shelf life of potatoes and onions ………………………. due to slowed-down of sprouting.
Answer:
increases

Question 17.
Serving too much food to guests at traditional feasts and banquets leads to ………………………. wastage of food.
Answer:
Quantitative

Question 18.
Miscalculation of the time required to transport food from producers to consumers leads to ……………………… . wastage of food.
Answer:
Qualitative

Question 19.
Prevention of food spoilage by microbial growth and infestation by pests is called ………………………. .
Answer:
food protection

Question 20.
………………………. is an example of a chemical preservative.
Answer:
Sodium benzoate.

Say whether True or False,, Correct and rewrite the false statement.

Question 1.
To prevent adulteration of food, it is inspected by the “Food and Drug Administration department of the government”.
Answer:
True

Question 2.
Overcooking of food increases the quality of food.
Answer:
False. Over cooking of food spoils it

Question 3.
Peanuts become rancid then, it is not good to eat.
Answer:
True

Question 4.
Oil and ghee contain fats.
Answer:
True

Question 5.
Prevention of food spoilage by microbial growth and infestation by pests is called food wastage.
Answer:
False. Prevention of food spoilage by microbial growth and infestation by pests is called food protection.

Question 6.
Serve yourself only as much as you can eat.
Answer:
True

Question 7.
Salt, sugar and oil are naturally available preservatives.
Answer:
True

Question 8.
Pickles can be preserved by salting.
Answer:
True

Question 9.
Milk vendors add urea to the milk so that it appears to have higher fat content.
Answer:
True

Question 10.
Shelf life of fruits and vegetables decreases by gamma rays emitted by radio-active isotopes.
Answer:
False. Shelf life of fruits and ‘ vegetables increases by gamma rays emitted by radioactive isotopes.

Give scientific reasons.

Question 1.
Refrigerators are used in the kitchen.
Answer:

1. Biological and chemical reactions in food materials are slowed down at low temperature.
2. As a result food remains in good condition for a longer period. Therefore refrigerators are used in the kitchen.

Question 2.
Potatoes and onions are treated with gamma rays.
Answer:
Potatoes and onions are treated with gamma rays because irradiation with gamma rays prevents their wastage due to sprouting and increases their shelf life.

Question 3.
Grains are sun-dried.
Answer:
Grains are sun-dried to preserve them because on sun drying their water content gets reduced and hence they last longer.

Question 4.
We boil milk from time to time.
Answer:
We boil milk from time to time to kill microorganisms in it and thus prevent it from getting spoilt.

Question 5.
Jams or pickles get spoilt if their jars are not sealed properly.
Answer:
If the jar is not sealed properly, micro¬organisms from the air enter in the jar and start growing on the food. Oxygen in the air helps the micro-organisms and fungi to grow faster and hence bring about the spoilage of the jams and pickles.

Question 6.
Some vendors add urea to the milk.
Answer:
Some vendors add urea to the milk so that it appears to have higher fat content.

Question 7.
Food wastage should be avoided.
Answer:
In countries like India, the food requirement is plenty and people do not get proper meals even once in a day. If food is not wasted then it could have met the need of many others. Therefore, food should not be wasted and proper measures should be implemented to stop quantitative and qualitative wastage of food.

Question 8.
Adulterated food should not be consumed.’
Answer:

1. The health of all people is endangered by food adulteration.
2. Different types of adulterants affect our health in different ways.
3. Some adulterants cause abdominal discomfort or poisoning, while some may affect the functioning of some organs if consumed over a long period of time or even cause cancer.

Can you tell?

Answer the following questions:

Question 1.
How and where food is wasted?
Answer:
Quantitative wastage of food:
1. Wrong methods of farming like hand sowing of, ts seeds, inadequate threshing, improper storage and wrong methods of distribution are some reasons for quantitative wastage of food.

2. Besides, much food is wasted as a result of the custom of offering and serving too much food to guests at traditional feasts or banquets.

3. Had it not been wasted, all this food could have met the need of many others Qualitative wastage of food: Using wrong methods of protecting food, excessive use of food preservatives, over-cooking, washing the vegetables after cutting them, mis-handling of fruits like grapes and mangoes, mis-calculation of the time required to transport food from producers to consumers, are some of the causes of quantitative wastage of food.

Question 2.
How is the food adulterated?
Answer:
Food is adulterated by the following ways:

1. Removal of some important components of food. e.g. removal of fat content of milk, essence of cloves, cardamoms, etc.
2. Mixing of a low quality inedible or cheaper material or harmful colour with food.
3. Mixing of some harmful materials like small stones, fine sand, iron filings, urea, dung of horse, sawdust etc.

How will you find out if food has been adulterated?

7th Std Science Questions And Answers:

• The Living World: Adaptations and Classification Class 7 Questions And Answers
• Plants: Structure and Function Class 7 Questions And Answers
• Properties of Natural Resources Class 7 Questions And Answers
• Nutrition in Living Organisms Class 7 Questions And Answers
• Food Safety Class 7 Questions And Answers
• Measurement of Physical Quantities Class 7 Questions And Answers
• Motion, Force and Work Class 7 Questions And Answers
• Static Electricity Class 7 Questions And Answers
• Heat Class 7 Questions And Answers
• Disaster Management Class 7 Questions And Answers

Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 1 Natural Resources – Air, Water and Land Notes, Textbook Exercise Important Questions and Answers.

Std 6 Science Chapter 1 Natural Resources – Air, Water and Land Question Answer Maharashtra Board

Class 6 Science Chapter 1 Natural Resources – Air, Water and Land Question Answer Maharashtra Board

1. Fill in the blanks and rewrite the completed statements.

Question a.
The layer of ozone gas absorbs ……………. rays that come from the sun to the earth.
Answer:
Ultraviolet (U.V) rays

Question b.
Of the total water available on the earth, fresh water forms ……….. percent.
Answer:
0.3 %

Question c.
Both …………. and ………… constituents are present in the soil.
Answer:
biotic, abiotic

2. why is it said that?

Question a.
The ozone layer is a protective shell of earth.
Answer:

1. The ultra violet (UV) rays coming from the sun are very harmful for living things.
2. The ozone layer present in the lower stratosphere absorb this U.V. rays and prevent them from reaching the earth. As a result life on earth is protected.
3. Therefore, it is said that the ozone layer is a protective shell of the earth.

Question 2.
Water is life.
Answer:

1. Water is a good solvent and it dissolves many substances.
2. The human blood is made of 70% water and the sap of plant also contains a very high proportion of water.
3. All the life processes would not take place in the absence of water.
4. Hence, without water no living organism can survive.
5. Therefore, it is said that ‘water is life’.

Question c.
Sea water is useful even though it is not potable.
OR
In what way is sea water useful even though it is salty?
Answer:

1. Many fish and aquatic animals live in sea water.
2. The water from the sea evaporates to form clouds which brings rain.
3. The sea water also helps the land to cool due to breezes.
4. The salt and minerals are also obtained from sea water.
5. Corals and pearls are obtained from sea animals.
6. Thus, sea water is useful even though it is not potable.

3.  What will happen if

Question a.

Question a.
Microbes in soil get destroyed.
Answer:

1. Microbes in the soil decompose dead plants and animals and convert it into humus. This humus supplies nutrients to the soil.
2. Humus also aerates soil and holds water in it. It makes the soil more fertile.
3. If microbes are destroyed, humus will not be formed and the soil will not become fertile, making it unsuitable for growth of plants. Also dead and decaying matter will accumulate on land.

Question b.
The number of vehicles and factories in your surroundings increases.
Answer:

1. Vehicles and factories are the major cause of air pollution.
2. They release harmful gases like carbon dioxide, carbon monoxide and sulphur dioxide into the air.
3. These pollutants are harmful to the environment and to the people living in the surrounding area.
4. Hence, if the number of vehicles and factories in our surroundings increases, the air pollution will also increase.

Question c.
The total supply of potable water is finished.
Answer:

1. Water plays very important role in the survival of living organism.
2. All living things are dependent on water.
3. A very small quantity of water is potable and can be used for drinking.
4. All bodily functions are regulated by water.
5. Therefore, if total supply of potable water is finished, plants and animals will not survive and there will be no life on earth.

4. Match the following. 

Question a.

Group ‘A’	Group ‘B’
1. Carbon dioxide	a. Generation of soil
2. Oxygen	b. Rain
3. Water vapour	c. Plants and food production
4. Microbes	d. Combustion

Answer:

Group ‘A’	Group ‘B’
1. Carbon dioxide	c. Plants and food production
2. Oxygen	d. Combustion
3. Water vapour	b. Rain
4. Microbes	a. Generation of soil

5. Name the following.

Question a.
Constituents of biosphere.
Answer:
Atmosphere, hydrosphere, lithosphere and all living things on earth.

Question b.
Biotic constituents of soil.
Answer:
Microbes, worms, insects, burrowing rhodents like rats, mice, roots of trees and plants.

Question c.
Fossil fuel.
Answer:
Crude oil from which we get kerosene, petrol, diesel, paraffin wax and tar.

Question d.
Inert gases in air.
Answer:
Neon, argon, helium, krypton, xenon.

Question e.
Gases that are harmful to ozone layer.
Answer:
Chlorofluorocarbon and carbon tetrachloride.

6. True or False?

Question a.
Land and soil is the same thing.
Answer:
False – Land consists of stones, soil and big rocks.

Question b.
The water in a lake is called ground water.
Answer:
False – Water trapped below the ground over the bedrocks is called ground water.

Question c.
It takes about thousand years to form a 25 cm thick layer of soil.
Answer:
False – It almost takes around thousand years to form a 2.5 cm thick layer of soil.

Question d.
Radon is used in decorative lights.
Answer:
False – Neon is used in decorative lights.

7. Answer in your own words. 

Question a.
Explain with the help of a diagram how soil is formed.
Answer:

1. The soil on the land is formed by a natural process.
2. The abiotic components of soil are supplied through the weathering of the bedrock.
3. Due to heat, cold wind and rain the bedrock breaks down into pieces.
4. Stones, sand and soil are formed from these pieces.
5. Microbes, worms, insects, rodents and roots of trees growing on land help in weathering of rocks.
   
   This process is slow, continuous and it takes a thousand years to form 2.5 cm thick layer of mature soil.

Question b.
Why is there a shortage of water even though it occupies about 71% of the earth’s surface?
Answer:

1. 71% of earth’s surface is covered with water of, which 97% is salty water present in seas and oceans and 2.7% water is available as ground water, ice and in other forms.
2. Only 0.3% water is available as fresh water which can be used for drinking.
3. All the living organisms require water to drink. The water is used in the industry and also for farming.
4. Due to increasing population and uncontrolled usage, we experience shortage of water.

Question c.
What are the various constituents of air? Write their uses.
Answer:
Air contains gases like oxygen, carbon dioxide, nitrogen, inert gases, water vapour and dust particles. The uses of constituents of air are as follows.

Question d.
Why are air, water and land considered to be valuable natural resources?
Answer:

1. The various components of air help and support the growth of living organisms.
2. Nitrogen is used to make proteins, oxygen is used for respiration and carbon dioxide is used to make food by plants.
3. Similarly, land supports growth of terrestrial plants and animals. It provides important minerals to plants and also to human beings.?
4. It is the shelter for worms, insects and rodents and supports their growth. Plants also cannot survive without land.
5. Water is necessary for carrying out all life processes in the living organisms and without water there will be no life on earth.
6. Hence land, air and water are considered valuable natural resources.

Activity:

Natural Resources Air, Water And Land Class 6 Questions And Answers Question 1.
Obtain detailed information about the work of the India Meteorological Department.

Natural Resources Air Water And Land Class 6 Questions And Answers Question 2.
Find a remedy for water scarcity.

Class 6 Science Chapter 1 Natural Resources – Air, Water and Land Important Questions and Answers

Fill in the blanks and rewrite the completed statements.

Class 6 Science Chapter 1 Natural Resources Air, Water And Land Exercise Question 1.
……………. gas, used for refrigeration and air conditioning, destroys the ozone layer.
Answer:
Chlorofluorocarbon or carbon tetrachloride

Natural Resources Air Water And Land Class 6 Exercise Question 2.
Air becomes ……………. at higher altitudes.
Answer:
rarer

Natural Resources Air Water And Land Class 6 Question 3.
………….. of land is reduced if green trees and bushes are grown in it.
Answer:
Erosion

Natural Resources Air Water And Land Question 4.
16th September is celebrated as ………. Day all over the world.
Answer:
Ozone Protection

Natural Resources Air Water And Land Question Answer Question 5.
………….. is the layer of air that surrounds the earth.
Answer:
Atmosphere

Natural Resources Air, Water And Land Question 6.
……………. occupies the largest part of the earth’s surface.
Answer:
Hydrosphere

Natural Resources Air Water And Land Class 6 Question 7.
Gases are not found in the …………… and beyond.
Answer:
exosphere

Choose the correct alternative:

Question 1.
………….. percentage of the land is covered by water.
(a) 70%
(b) 81%
(c) 71%
(d)80%.
Answer:
71%

Question 2.
The gas used in fluorescent tubes is ………………… .
(a) Argon
(b) Helium
(c) Neon
(d) Krypton.
Answer:
Krypton

Question 3.
The ozone layer is found in the lower part of …………… .
(a) atmosphere
(b) stratosphere
(c) mesosphere
(d) trophosphere.
Answer:
stratosphere

Question 4.
Gas released in air on combustion of fuel is …………….. .
(a) Hydrogen sulphide
(b) Carbon tetrachloride
(c) Nitrogen dioxide
(d) Oxygen
Answer:
Nitrogen dioxide

Question 5.
The proportion of humus in the upper layer of good fertile soil is about ……………… .
(a) 23% to 45%
(b) 33% to 50%
(c) 30% to 53%
(d) 13% to 33%
Answer:
33% to 50%

Match the following:

Question 1.

Group ‘A’	Group’B’
1. Argon	a. temperature for obtaining low
2. Neon	b. Used in electric bulb
3. Xenon	c. Decorative lights
4. Chlorofluoro – carbon	d. Flash photography
5. Helium	e. Ozone depletion

Answer:

Group ‘A’	Group’B’
1. Argon	b. Used in electric bulb
2. Neon	c. Decorative lights
3. Xenon	d. Flash photography
4. Chlorofluoro – carbon	e. Ozone depletion
5. Helium	a. temperature for obtaining low

Name the following:

Question 1.
Substances formed when fuel burns.
Answer:
Carbon dioxide, carbon monoxide, nitrogen dioxide, sulphur dioxide and smoke.

Question 2.
Layers of the atmosphere.
Answer:
Troposphere, stratosphere, mesosphere, ionosphere and exosphere.

Question 3.
Layers of land.
Answer:
Humus, mature soil, immature soil, small rocks and stones and bedrock.

Question 4.
Gas necessary for building proteins.
Answer:
Nitrogen.

State whether True or False. Correct if False.

Question 1.
The amount of gases in the air is greatest near the surface and becomes rarer at higher altitudes.
Answer:
True.

Question 2.
Fogs, clouds, snow, and rain are produced in the exosphere.
Answer:
False – Fogs, clouds, snow and rain are formed in the troposphere and lower stratosphere of the atmosphere.

Question 3.
Fossil fuels are formed from the dead remains of animals and plants buried underground for a long period.
Answer:
True.

Explain what will happen if:

Question 1.
Forests are destroyed.
Answer:

1. Soil will get eroded due to rains as roots of trees hold the soil.
2. The land will become barren as trees helps to increase the level of ground water.
3. Amount of carbondioxide in the air will increase as trees use carbondioxide for photosynthesis and release oxygen.
4. Natural habitat of many animals will get completely destroyed.

Question 2.
What would have happened if there was no air on the earth?
Answer:

1. Air contains gases like nitrogen, oxygen, carbon dioxide, dust particles and water vapour, which are used in various piofeesses in living organisms and environment.
2. If there is no air then there will be no life as oxygen is essential for all living beings to survive. Also atmosphere is a very important filter. It prevents die harmful elements from reaching the earth.
3. Hence without air, our earth would become a cold, dark planet without any life.

Answer the following:

Question 1.
What is humus?
Answer:
Humus is the topmost layer of the soil formed d by decomposition of remains of plants and animals and it makes the soil fertile.

Question 2.
What is land made up of?
Answer:
Land is made up of stones, soil, sand and big rocks.

Question 3.
Is land flat everywhere?
Answer:
No, land is not flat everywhere. It is flat in some regions and hilly in some regions.

Question 4.
Does man produce soil/ land?
Answer:
No, man does not produce soil/land, it is produced naturally.

Question 5.
What do you see on land?
Answer:
We see mountains, rivers, valleys, ocean, also terrestrial animals and plants. We also see roads, bridges, buildings etc.

Question 6.
What has man created on land?
Answer:
Man has dug wells, borewells to lift ground water. He has also constructed bunds and dams. He has also built many industries, buildings, roads for transport.

Question 7.
If a deep pit is dug in the ground, what do you see there?
Answer:
We see different layers of land.

Answer in your own words.

Question 1.
Explain with the help of diagram various layers of land.
Answer:

• Humus – Topmost layer, fertile layer formed by decomposition of remains of plants and animals. Immature
• Soil – Sand, soil, small stones, worms and insects.
• Layer of soil and small rocks – less soil and more rocks.
• Bedrocks – main minerals are obtained from this layer, determines colour and texture of soil.

Observe the picture and answer the questions.

Question 1.
Where do you see the birds?
Answer:
The birds are flying in the sky.

Question 2.
Where is the cow grazing?
Answer:
The cow is grazing in the pasture (field).

Question 3.
Locate the trees.
Answer:
The trees are seen along the river bank.

Question 4.
Where does the river come from?
Answer:
The river flows from the mountains towards the plains.

Question 5.
Where is the aeroplane?
Answer:
The aeroplane is in the sky above the clouds.

Question 6.
Where are fishes seen?
Answer:
Fishes are seen swimming in the river water.

Question 7.
On what is the sail boat floating?
Answer:
Sail boat is floating on the water.

Observe and discuss:

Question 1.
What is the similarity in the three pictures given above?
Answer:
All the pictures given above show large scale emission of smoke through different agencies. This smoke directly mixes with the atmosphere, disturbing the balance between the constituents of air and causing air pollution.

Observe and discuss:

Observe the distribution of water on the earth surface and complete the table.

Question 1.

Answer:

Water available on earth	percentage
Seas, oceans	97%
Groundwater and water in other forms	2.7%
Water available for drinking	0.3%
Total	100%

Observe given figure carefully and answer the following.

Question 1.
For which purpose is water being used?
Answer:
Water is being used for washing clothes, for bathing, farming, drinking, and industries.

Question 2.
Do other living things use water like we do?
Answer:
Animals do not use water like us. They use water only for drinking. Some animals like buffaloes, rhinoceros, elephants use water for cooling themselves during summers.

Question 3.
What are the constituents of soil? Classify them as biotic and abiotic constituents.
Answer:
The constituents of soil are humus, soil, sand, gravel, stones, bedrock, insects, worms, microbes, roots of trees and dead leaves, burrowing rodents like mice and rats.

Biotic	Abiotic
Microbes, rodents like mice and rats, humus containing microbes and dead leaves.	Soil, sand, gravel, stones, bedrock.

Answer the following:

Question 1.
How would you save water? Give some measures you will adopt.
Answer:
Water can be saved in the following ways:

1. Repair the leaking taps and pipes and prevent wastage of water.
2. Take water in a bucket to wash a car, rather than using a hose pipe.
3. Close the tap when not required.
4. Store rainwater in underground tanks so that it can be used all round the year.
5. Water leftover after washing vegetables etc. can be used for watering plants in the garden.
6. Use water sparingly and reuse water wherever possible.

Question 2.
What measures would you take to prevent soil erosion?
Answer:

1. The trees, bushes and grass shall be planted in open spaces.
2. Shrubs will be planted along the river banks to prevent floods.
3. Proper drainage system will be provided so that there is no flooding of water.

Let’s try this

1. Take a transparent plastic bottle, a handful of soil, big stones, small stones, sand, some dry leaves and water.
2. Cut off the upper tapering part of the bottle. Put the rest of the materials in the lower part and add water.
3. Stir the mixture thoroughly and put it aside.

Observe it the next day and answer.

Question 1.
How does the mixture in the bottle look now?
Answer:
The mixture gets segregated into various layers. Heaviest substances settle down and lighter forms topmost layer.

Question 2.
Do you see the layers in it?
Answer:
Yes, we see the layers of soil.

Question 3.
What is seen in the different layers from top to bottom?
Answer:
The dry leaves are floating above the water at the top. Then the layer of the soil, which forms a layer above the sand. Below the sand we see a layer of small stones, and the big ones have settled down at the bottom of the bottle.

Question 4.
Obtain specimens of soil from various places and note the differences in the specimen with respect to colour, feel, texture and size of the particles.
Answer:

Area from where soil sample is taken	Colour	Texture
1. Own yard	Red colour	Smooth soil which is dry.
2. Garden	Black colour	Sticky soil, rich in humus and insects.
3. Hills	Red colour	Rough soil with small stones and pebbles.
4. River banks	White colour	Sandy and moist in nature.
5. Fields	Black soil	Sticky soil with fine particles, rich in humus and worms.
6. Rocky ground	Black	Coarse with stones and pebbles, hardly any fine soil is seen.

Question 5.
Observe how much water is used and for what purposes it is used in your house for a whole day. Record it in a chart. Discuss this data and find out how much water each person needs in your house.
Answer:

Purpose for which water is used	Amount of water (approx in litres)
1. Bath	50 litres
2. Brushing teeth	1 litre
3. Washing clothes and utensils	75 litres
4. Mopping the floor	10 litres
5. Drinking	8 litres
6. Cooking	6 litres
Total use of water	150 litres

Total number of persons = 3
Total water used per person = \(\frac{50}{3}\) = 50 litres.
Approximately 50 litres of water is required for 1 person.

Class 6 Questions And Answers

6th Std Science Questions And Answers:

• Natural Resources – Air, Water and Land Class 6 Questions And Answers
• The Living World  Class 6 Questions And Answers
• Diversity in Living Things and their Classification Class 6 Questions And Answers
• Disaster Management Class 6 Questions And Answers
• Substances in the Surroundings – Their States and Properties Class 6 Questions And Answers
• Substances in Daily Use Class 6 Questions And Answers
• Nutrition and Diet Class 6 Questions And Answers
• Our Skeletal System and the Skin Class 6 Questions And Answers
• Motion and Types of Motion
• Force and Types of Force Class 6 Questions And Answers

Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 14 Light and the Formation of Shadows Notes, Textbook Exercise Important Questions and Answers.

Std 6 Science Chapter 14 Light and the Formation of Shadows Question Answer Maharashtra Board

Class 6 Science Chapter 14 Light and the Formation of Shadows Question Answer Maharashtra Board

1. Choose an appropriate word and fill in the blanks.

Question a.
A ……………. is a natural source of light.
Answer:
star

Question b.
A ………….. is an artificial source of light.
Answer:
candle

Question c.
When light passes through a prism, it gets separated into ………….. colours.
Answer:
seven

Question d.
The image obtained in the pinhole camera is …………. .
Answer:
inverted

Question e.
A shadow is formed when an …………… object comes in the way of light.
Answer:
opaque

Question f.
When a ………….. object comes in the way of light, light passes …………… it. options : seven, star, through, transparent, opaque, colors, shape, erect, inverted, luminous, candle.
Answer:
transparent, through

2. Write whether the following objects are luminous or non-luminous.

Question a.

Answer:

Object	Luminous /Non-luminous
A book	Non-luminous
A burning candle	Luminous
A wax cloth	Non-luminous
A pencil	Non-luminous
A pen	Non-luminous
A light bulb	Luminous
A tyre	Non-luminous
A torch	Luminous
Stars	Luminous
The planets	Non-luminous
A satellite	Non-luminous
The Moon	Non-luminous

3. Match the following.

Question a.

Natural sources of light	Man-made sources of light
The Sun	Tubelight
Stars in the night sky	Light bulb
Fireflies	Torch
Anglerfish	Burning candle
Honey mushroom	Oil lamps

Answer:

Transparent	Opaque	Translucent
Piece of glass Water	White plastic Tea kettle Note book Cloth Wooden cupboard	Tinted glass Oil paper Sheet of notebook Wax paper

4. Write the answers to the following.

Question a.
What things are necessary for the formation of a shadow?
Answer:
Things necessary for the formation of a shadow are:

1. A source of light
2. An object
3. A surface or screen on which the shadow is formed

Question b.
When can an object be seen?
Answer:
We can see an object when reflected rays reach our eyes.

Question c.
What is a shadow?
Answer:

1. If an opaque object comes in the way of a light source, light does not pass through it.
2. As a result the light does not reach a wall or any other surface on the other side of the object.
3. That part remains dark. This dark part is called the shadow of the object.

Project:

Question 1.
Prepare a Newton’s disc.

Question 2.
Find out how to save electricity with the help of the sunlight we receive during the day.

Question 3.
Read a biography of Sir C. V. Raman and find out about the discoveries he made.

Class 6 Science Chapter 14 Light and the Formation of Shadows Important Questions and Answers

Fill in the blanks.

Question 1.
The ……………. is the main natural source of light.
Answer:
Sun

Question 2.
The light emitted by an electric torch is more …………….. than that obtained from a candle.
Answer:
intense

Question 3.
The left and right sides of the original object appear to be …………….. in the mirror.
Answer:
exchanged

Question 4.
The image is as far behind the mirror as the object is in ……………… of it.
Answer:
front

Question 5.
The …………….. of the image is the same as that of the object.
Answer:
height

Question 6.
The materials through which light passes is said to be …………… .
Answer:
transparent

Question 7.
The materials through which light does not pass is said to be ………….. .
Answer:
opaque

Question 8.
The materials through which light passes partially is said to be ………….. .
Answer:
translucent

Question 9.
If an ………….. object comes in the way of a light source, light does not pass it.
Answer:
opaque, through

Question 10.
The shadow of an object formed due to sunlight is ………….. in the mornings and evenings and ……………. in the afternoon.
Answer:
long, short

Question 11.
The shadow of an object is formed only when ………….. does not pass through the object.
Answer:
light

Question 12.
Stars are ………….. .
Answer:
luminous

Question 13.
Planets, satellites are ………….. .
Answer:
non-luminous

Question 14.
The largest sundial is at ………….., New Delhi.
Answer:
Jantar Mantar

Question 15.
………….. is celebrated as National Science Day.
Answer:
28th February

Question 16.
Light travels in a straight line. This is called ………….. .
Answer:
linear propagation of light

Question 17.
The image formed on the diaphragm of the pinhole camera is ………….. .
Answer:
inverted

Question 18.
The kind of shadow an object forms depends upon the ………….. between the ………….., the object and the ………….. or the ………….. on which the shadow is formed.
Answer:
relative distance, source of light, surface, screen

State whether following statements are True or False.

Question 1.
Light travels in a straight line.
Answer:
True

Question 2.
Stars are luminous.
Answer:
True

Question 3.
Image in a pinhole camera is inverted.
Answer:
True

Question 4.
In the afternoon, shadows are long.
Answer:
False

Question 5.
Fireflies are a natural source of light.
Answer:
True

Question 6.
We see the candle clearly when we bend the tube.
Answer:
False

Question 7.
We can see our image clearly in running water.
Answer:
False

Question 8.
Tracing paper is transparent.
Answer:
False

Question 9.
The light obtained from an electric torch is more intense than that obtained from a candle.
Answer:
True

Question 10.
28tn February is celebrated as “National Science day” since 1987 in India.
Answer:
True

Question 11.
Classify the following into natural and man-made/artificial sources of light. (tubelight, light bulb, torch, burning candle, the sun, fireflies, anglerfish, honey mushroom, stars in the night sky, oil lamps, lanterns)
Answer:

Natural sources of light	Man-made sources of light
The Sun Stars in the night sky Fireflies Anglerfish Honey mushroom	Tubelight Light bulb Torch Burning candle Oil lamps Lanterns

Question 12.
Identify the transparent, opaque and translucent objects from among the following. (piece of glass, wax paper, tinted glass, oil paper, white plastic, a tea kettle, a notebook, cloth, water, a wooden cupboard, sheet of notebook.)
Answer:

Transparent	Opaque	Translucent
Piece of glass Water	White plastic Tea kettle Notebook Cloth Wooden cupboard	Tinted glass Oil-paper Sheet of notebook Wax paper

Question 13.
Classify the following into the type of images they form: Clear image, faint image, no image. (still clear water, cemented wall, wooden surface, new steel dish, flower, glossy granite cladding of a wall, mirror, butter paper).
Answer:

Clear Image	Faint Image	No Image
Still clear water, New steel dish, Glossy granite cladding of a wall, Mirror	Butter paper	Wooden surface Flower Cemented wall

Question 14.
Relate images formed with the surfaces.
Answer:

1. The clear images are formed on plane surfaces.
2. Faint or no images are formed on rough surfaces.

Answer in one sentence.

Question 1.
What are luminous objects?
Answer:
The objects which emit light i.e. which themselves are a source of light, are called luminous objects.

Question 2.
What determines the intensity of light?
Answer:
The intensity of light is determined by the extent to which the objects emit light.

Question 3.
What are non-luminous objects?
Answer:
The objects that are not sources of light themselves are called as non-luminous objects.

Question 4.
What are artificial sources of light?
Answer:
Man-made objects which emit light are artificial sources of light.

Question 5.
What are natural sources of light?
Answer:
Natural substances, materials which emit light are called natural sources of light.

Question 6.
What is linear propagation of light?
Answer:
Property of light travelling in a straight line is linear propagation of light.

Question 7.
What is reflection of light?
Answer:
The rays of light falling on an object from a source of light are thrown back from the substance of that object. This is reflection of light.

Question 8.
How do we see objects around us?
Answer:
The rays of light falling on an object from a source of light are thrown back from the surface of that object. This is called reflection of light. We see the object when the reflected rays reach our eyes.

Question 9.
What is moonlight?
Answer:
Sunlight reflected from the surface of the moon reaching us, in which we see the moon is called the moonlight.

Question 10.
What type of image is formed in the mirror?
Answer:
The image formed in the mirror is ‘laterally inverted’ i.e. right side appears as left side and left side appears as right side.

Question 11.
What change do you see in the image if you decrease or increase your distance from the mirror?
Answer:
When the distance between object and mirror is increased the size of image decreases where as, when the distance is decreased the image size increases.

Question 12.
What difference do you find in the height of the image in the mirror and yourself?
Answer:
The size of the image in the mirror is the same as that of the object.

Question 13.
What is the image on the diaphragm of the pinhole camera?
Answer:
An inverted or an upside down image of the candle is seen on the diaphragm of the pinhole camera.

Question 14.
What do you mean by transparent object?
Answer:
The objects / materials through which light passes are said to be transparent.

Question 15.
What do you mean by opaque materials?
Answer:
The materials through which light does not pass are said to be opaque.

Question 16.
What do you mean by translucent materials?
Answer:
The materials through which light passes partially are said to be translucent.

Question 17.
How is the shadow in the morning, afternoon and evening?
Answer:
The shadows are long in the mornings and evenings and short in the afternoon.

Question 18.
What is shade of a tree?
Answer:
The shade of a tree is its shadow.

Question 19.
How many colours is sunlight made up of?
Answer:
Sunlight is made up of seven colours.

Give reasons for the following.

Question 1.
When we see in the mirror, we see our image in the mirror.
Answer:
When we see our face in the mirror, the light reflected from our face falls on the mirror and gets reflected back again. Hence, we see our image in the mirror.

Question 2.
Opaque materials cast shadow.
Answer:
An opaque material does not allow light to pass. Hence, it casts a shadow.

Question 3.
Transparent and translucent object do not cast a shadow.
Answer:
Translucent objects cast a faint shadow whereas transparent objects do not cast a shadow at all because they allow light to pass through them.

Use your brain power!

Question 1.
Why is the image on the diaphragm of the pinhole camera inverted?
Answer:
1. The pinhole camera works on the principle of light travelling in a straight line.
2. The rays of light from the candle flame go in all directions.
3. We consider only two rays that pass through the hole and fall on the screen.

4. The rays intersect at the pinhole.
5. Since the rays cross over at that point, the top of the object appears at the bottom of the image and the bottom of the image appears at the top. Thus, we see an inverted image of the candle.

Question 2.
How will you light up a dark room using reflected light?
Answer:
Focusing on the wall with torch light. Mirrors or reflectors can be used to get light from outside.

Question 3.
Try to start the TV by operating the remote control from behind it.
Answer:
T.V will not start.

Question 4.
In which step is the flame of the candle seenclearly? Why?

Answer:
In step 1 the flame of the candle is seen clearly because light travels in straight line.

Can you tell?

Question 1.
Can we see anything in total darkness?
Answer:
No, we cannot see anything in total darkness.

Question 2.
What helps us to see the objects around us?
Answer:
Reflected light helps us to see objects around us.

Question 3.
What does the light in each one of the pictures originate form?
Answer:

1. Bulb
2. Firefly
3. Candle
4. Sun

Question 4.
Name the natural sources of light.
Answer:
Sun, Fireflies

Question 5.
In which objects do we see our reflection?
Answer:
All objects reflect light rays, but the best reflectors of light are mirrors, still water in a lake, new steel dish i.e. smooth shiny surfaces.

Question 6.
What difference do you notice on looking through the windows in the picture? What causes the difference? The picture shows transperant, opaque, translucent window panes. Spot them.

Answer:

1. Through the first window we can see a clear picture of things outside.
2. Second window gives a faint image.
3. Through the third window, we can’t see anything
4. The difference in the image is due to the material of the window panes.
5. The first window pane is transparent.
6. The second window pane is translucent.
7. The third window pane is opaque.

Answer the following questions in brief.

Question 1.
List factors on which shadow depends.
Answer:
Shadow depends on relative distance between the source of light, the object and the surface on which the shadow is formed.

Question 2.
How we can see that light travels in straight line.
Answer:

1. In the morning or in the afternoon, rays of light enter a slit in a door, window or a small hole in the roof.
2. As these rays of light from the slit or the hole move towards the floor, the dust particles in their way are clearly seen.
3. Due to these particles, the path of light becomes visible to us.
4. Thus we can see that their path is along straight lines.

Question 3.
What is the difference between an object and its reflection? What causes the difference?
Answer:

1. Object and its reflection result in formation of images.
2. Reflections taking place from highly polished metals, mirrors, still water etc, form clear images.
3. Reflections taking place from wooden surface, flower, book form dull, blurred images.
4. The difference in reflections is caused by the surface of the object.
5. Regular reflections have smooth, polished surfaces, hence, image is clear.
6. Diffused reflections have hard, rough surfaces, hence, image is dull.

Question 4.
List characteristics of images in a plane mirror.
Answer:

1. The left and right sides of the original object appear to be exchanged in the mirror image.
2. The image is as far behind the mirror as the object is in front of it.
3. The size of the image is the same as that of the object.

Question 8.
State the characteristics of image formed by a pinhole camera.
Answer:
Characteristics of an image formed by a pinhole camera are as follows:

1. It is inverted/upside down.
2. It can be obtained on a screen – real image.

Try this.

Question 1.
Make your friend stand in between the torch and the wall. What happens?
Answer:
Friend’s Shadow forms on the wall.

Question 2.
Place a glass filled with water on a sheet of paper in the window so it receives direct sunlight. What is seen on the paper?
Answer:
We see rainbow colours on the paper.

Question 3.
Can we do the same in a dark room with the help of a prism and a torch? What do we learn from this?
Answer:
yes, we can. Light gets seperated into seven colour. From this we learn that white light contains seven colours.

Question 4.
If you dip the wire loop in the soap water and then blow it, soap bubbles are formed. Are the beautiful colours of the rainbow seen in these bubbles?
Answer:
Yes, splitting of white light into different colours takes place.

Question 5.
What do you see on holding a CD in the sun?
Answer:
CD reflects rainbow colours, and interesting : patterns.

Question 6.
Raise your right hand. In mirror which hand of the mirror image is raised?
Answer:
Left hand of the mirror image is raised.

Question 7.
Is there any difference between your height and height of the mirror image?
Answer:
The height remains the same.

6th Std Science Questions And Answers:

• Work and Energy Class 6 Questions And Answers
• Simple Machines Class 6 Questions And Answers
• Sound Class 6 Questions And Answers
• Light and the Formation of Shadows Class 6 Questions And Answers
• Fun with Magnets Class 6 Questions And Answers
• The Universe Class 6 Questions And Answers