Bhagya

Sound: Production of Sound Class 7 Science Chapter 18 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 18 Sound: Production of Sound Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 18 Sound: Production of Sound Question Answer Maharashtra Board

Class 7 Science Chapter 18 Sound: Production of Sound Question Answer Maharashtra Board

1. Fill in the blanks:

Question a.
Sound is generated by the rhythmic ……………. of any object.
Answer:
vibrations

Question b.
The frequency of sound is measured in …………….. .
Answer:
Hertz (Hz)

Question c.
If …………….. of sound is decreased its loudness also decreases.
Answer:
intensity

Question d.
A medium is necessary for …………… of sound.
Answer:
generation

2. Match the pairs.

Question a.

Column ‘A’	Column ‘B’
1. Flute	a. Frequency less than 20 Hz
2. Frequency	b. Frequency more than 20,000 Hz
3. Sound level	c. Vibrations in the air
4. Ultrasonic sound	d. Measured in Hz
5. Infrasonic sound	e. Decibel

Answer:

Column ‘A’	Column ‘B’
1. Flute	c. Vibrations in the air
2. Frequency	d. Measured in Hz
3. Sound level	e. Decibel
4. Ultrasonic sound	b. Frequency more than 20,000 Hz
5. Infrasonic sound	a. Frequency less than 20 Hz

3. Give scientific reasons.

Question a.
In earlier times, people used to listen for the arrival of a distant train by putting their ear to the rails.
Answer:

It was a technique that worked better in those days when train speed were slower than they are today and when there were more rail joints.
When people would put their ear to the rail they could hear vibration caused by the wheels moving over the joints. ,
Metal being a solid is an efficient medium for the sound to travel and so the sound can propagate further in the rail than would in air as speed of sound is faster in solids than in air.

Question b.
The sounds generated by a tabla and sitar are different.
Answer:

In tabla where leather is fitted, sound gets generated when the leather surface is thumped by fingers or palm.
The waves thus created travel in two dimensions. Sitar is having strings attached to pumkin box called sound box.
Sounds generated by tabla and a sitar are different because they have different pitch and frequencies.

Question c.
If you were both on the moon your friend will not be able to hear you call.
Answer: Yes, your friend will not be able to hear your call because sound needs a medium for transmission since it is a mechanical wave it cannot travel through vaccum.

As there is no air on the moon and sound is actually vibration in air.
So astronauts communicate to each other by signals or microphones in space even when they are closer.

Question d.
We can hear the movement of a mosquito wings but we cannot hear the movement of our hands.
Answer:

Humans cannot hear frequency less than 20 Hz. In the movement of hands oscillations does take place but is less than frequency that humans can hear.
Mosquitos wings flap in air.
When they fly in air it produces buzzing sound in our ears.
The movement of mosquito wings produces sound greater than 20 Hz.
Sound is the reception of such waves and their perception by the brain.

4. Write answers to the following questions.

Question a.
How is sound produced?
Answer:

Sound is generated due to the vibration of an object, e.g. bell, string or diaphragm of a musical instrument.
Vibrations are imparted to the molecules in the air. These vibrations reach our ears through the air and sound is heard.
Vibrations of an object is necessary for generation of sound.
These vibrations in air are called travelling longitudinal waves which we can hear.

Question b.
What does the intensity of sound depend upon?
Answer:

The intensity of sound is proportional to the square of the amplitude of vibration, e.g. If the amplitude is doubled the intensity of sound becomes four times.
Therefore the loudness or softness of sound is dependent on the intensity of sound and sound level.

Question c.
Explain how the frequency of oscillation is related to the length of a pendulum and the amplitude of its oscillation.
Answer:

1. Given an oscillatory motion to the pendulum, the maximum distance between the original position A of the pendulum and extreme position B or C is called the amplitude of oscillation. AB, AC is the amplitude of oscillation.
2. The number of oscillations completed by an oscillator in one second is called the frequency of oscillation.

Relation between frequency and length of a pendulum: If the length of the pendulum increases the period of oscillations also increases.
We know time period of oscillations = \(\frac{1}{\text { Frequency }}\)
If time period increases, frequency decreases, therefore, if the length of the pendulum increases frequency will decrease.
Relation between frequency and amplitude: Frequency of oscillation is independent of its amplitude of oscillation.

Question d.
Explain the two ways by which the pitch of the sound generated by a stretched string can be changed?
Answer:
1. A string vibrates with a particular fundamental frequency. It is however possible to produce pitches with different frequencies from the same string.

2. The two properties of the string that affect its frequency are length and diameter.

3. When the length of a string is changed, it will vibrate with a different frequency. Shorter strings have higher frequency and therefore higher pitch.

4. When a musician presses her finger on a string, she shortens its length. The more fingers she adds to the string, the shorter she makes it, higher will be the pitch.
Diameter: Thick strings with large diameter vibrate slower and have lower frequency than the thin ones.

Project:

Question a.
The bat, a mammal, flies during the night manoeuvering with the help of the ultrasonic sounds it produces. Find out more about this.

Class 7 Science Chapter 18 Sound: Production of Sound Important Questions and Answers

Fill in the blanks:

Question 1.
Bats detect the obstacles in their path by receiving the reflected ………….. .
Answer:
ultrasonic waves

Question 2.
An object that moves back and forth is called ……………. .
Answer:
an oscillator

Question 3.
If the length of a pendulum is increased the time period of oscillation ………………. .
Answer:
increases

Question 4.
The …………… of a wave is the maximum distance moved by the object on either side of the mean position.
Answer:
amplitude

Question 5.
Sound waves do not travel through ……………… .
Answer:
vaccum

Question 6.
The frequency above which sound is not audible to the human ear is …………….. .
Answer:
50,000 Hz

Question 7.
Number of vibrations in a second is called …………….. .
Answer:
frequency

Question 8.
Higher the frequency greater will be the ………….. .
Answer:
Pitch

Question 9.
The loudness of sound depends on ………….. .
Answer:
amplitude

Question 10.
Loudness of sound is measured in units of ………………. .
Answer:
decibel dB

Question 11.
100 hertz is equal to hundred oscillations in ………………. .
Answer:
one second

Name the following:

Question 1.
The sound frequencies above 20,000 Hz.
Answer:
ultrasonic

Question 2.
The medium through which sound is most clearly propagated.
Answer:
solids

Question 3.
The range of frequency in which humans can hear sound.
Answer:
20 – 20,000 Hz

Question 4.
The sound level physically painful to humans.
Answer:
above 100 dB

Question 5.
The technique used by bats to find their way.
Answer:
echolocation

Question 6.
The unit of frequency of sound.
Answer:
Hertz

Question 7.
The unit of sound level or intensity.
Answer:
Decibel

Question 8.
The scientist in whose honour was the unit decibel named for intensity of sound.
Answer:
Alexander graham Bell

Question 9.
Bats and dolphins can hear these sound frequencies.
Answer:
Ultra sonic sound

Question 10.
The sound frequencies used in RADAR systems.
Answer:
Ultra sonic sound

Answer in one or two sentences:

Question 1.
How is sound produced?
Answer:
Sound is produced by vibration of an object.

Question 2.
What produces sound in human beings ?
Answer:
The vibration of the vocal chords in our larynx or voice box produces sound.

Question 3.
What is oscillatory motion?
Answer:
To and fro motion of an object (oscillator) on either side of a central position is called oscillatory motion.

Question 4.
What is periodic motion?
Answer:
The motion of an object repeated again and again at fixed intervals of time is called periodic motion.

Question 5.
What is frequency of oscillation?
Answer:
The number of oscillations completed by an oscillator in one second is called the frequency of oscillation.

Question 6.
How is intensity of sound and amplitude of vibration related?
Answer:
The intensity of sound is proportional to the square of the amplitude of vibration. For example, if the amplitude is doubled the intensity becomes four times as much.

Question 7.
What happens if the frequency of sound is greater than 1000 Hz or 100 dB?
Answer:
If frequency of sound is increased more than 100dB, the hearing can be temporarily affected which can result in temporary deafness.

Question 8.
What is infrasonic sound?
Answer:
A sound with a frequency less than 20Hz is called infrasonic sound.

Question 9.
What is application of ultrasonic sound?
Answer:
Ultrasonic sound is used in ships as a system known as ‘SONAR’ to detect the obstacle beneath the ocean as well as the depth of an ocean.

Question 10.
What is the difference between pitch and frequency?
Answer:
Pitch is directly proportional to the frequency of a sound whereas frequency is the repeating vibrations per unit time.

Question 11.
What happens when the rubber band is stretched with a greater force and released?
Answer:
When a rubber is stretched with a greater force and released, the amplitude increases which in turn result in a louder sound being generated.

Question 12.
What happens to frequency if the amplitude is changed?
Answer:
The frequency remains the same even if the amplitude is increased or decreased.

Define:

Echo: It is a repetition of sound due to the reflection of original sound by a large and hard obstacle.
Frequency: It is defined as the number of vibrations per unit time.
Hertz (Hz): One hertz is one vibration per second.
Ultrasonic vibration: Sounds of frequency higher than 20,000 Hz are called the ultrasonic.
Time period: The time taken by an object to complete one oscillation is called time period.
Amplitude: The distance between the mean or central position to the extreme position of an oscillator on either side is called amplitude.

Say True or False with explanation:

Question 1.
Sound cannot travel in vacuum.
Answer:
True. Sound needs a medium to travel through. Since vacuum does not provide any medium, sound cannot travel through it.

Question 2.
If the amplitude of vibration is large, sound is feeble.
Answer:
False. When the amplitude of vibration of a sound is large, the sound is very loud. The sound is feeble, when the amplitude is small. Loudness of a sound is proportional to the square of the amplitude of its vibration.

Question 3.
For human ears, the audible range is 2 Hz to 20,000 Hz.
Answer:
True. Human being can hear sounds only within the range of 20-20,000 Hz. We cannot hear the sound having frequency out of this range.

Question 4.
The lower the frequency of vibrations the higher is the pitch.
Answer:
False. Pitch of sound increases when the frequency of vibration increases. The pitch of a sound is directly proportional to its frequency.

Question 5.
Unwanted or unpleasant sound is termed as music.
Answer:
False. Unwanted, or unpleasant sounds are termed noise. Sounds which are melodious, and pleasing to ears are called music.

Question 6.
Noise pollution may cause partial hearing impairment.
Answer:
True. Unwanted, unpleasant sounds are called noise. If one is subjected to noise continuously for a long time, one may suffer from partial hearing impairment.

Question 7.
Time taken by an object to complete one oscillation is called time period.
Answer:
True. Time taken by an object to complete one oscillation is called time period.

Solve the following problems:

Question 1.
A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.
Answer:
Frequency is the number of oscillations per second of a vibrating body.

The time taken to complete one oscillation (to and fro) is known, as time period.

Question 2.
The sound from a mosquito, is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?
Answer:
The time taken to complete one oscillation (to and fro) is know as time period.

Give scientific reasons:

Question 1.
Loud speakers should not be put in congested areas.
Answer:

The loudness or softness is indicated by the intensity of sound and sound level.
By putting loud speakers in congested areas, the intensity of sound being more than 100 dB will cause ill effects like temporary deafness and a prolonged exposure can lead to permanent damage.

Answer the following:

Question 1.
Why are the ceilings of concert halls curved?
Answer:
The ceilings of concert halls are curved because sound after reflection from the ceiling it reaches all the comers of the hall and is audible to each person in the hall.

Question 2.
Have you ever heard the sound of movement of hands and falling of leaves from a tree?
Answer:

The term infrasonic refer to sound waves below the frequencies of audible sound i.e. under 20 Hz.
Humans cannot hear infrasonic sound.
Movement of hands and falling of leaves comes below this audible range. Therefore we cannot hear these sounds.

Question 3.
How can dogs perceive in advance the signals of an impending earthquake?
Answer:
Dogs can hear sounds upto about 65,000 Hz. That’s why dogs can receive ultrasonic sound signals produced by the vibration of the earth and start barking in advance before the actual earthquake is felt.

Question 4.
State the uses of Ultrasonic sound.
Answer:
Uses of Ultrasonic sound are:

To clean delicate ornaments and the tiny parts of a watch.
To observe internal organs of the body.
To detect tumors in the brain.
To detect faults in a metal.
In RADAR systems
To Kill certain microbes and insects.
SONAR (Sound navigation and ranging) is used to locate the seabed or the position of a ship.

Use your brainpower!

Answer the following questions:

Question 1.
Will a sound be generated no matter how the ruler is kept on the table.

Answer:

No, If the ruler kept on the table is only a little part off the table, it will not vibrate with a greater force.
On the contrary if the ruler is kept with a larger portion off the table it will vibrate with a greater force generating louder sound.

Question 2.
Is there any correlation between the length of the free part of the ruler and the sound generated?
Answer:
Yes, vibrating ruler pushes the molecules in the air producing sound waves. More the length of free part of ruler less will be the vibrations and less will be the frequency and pitch of the sound. If the length of free part of ruler is shorter it vibrates more quickly producing sound of higher frequency and pitch.

Question 3.
If the ruler is plucked while it is held with 25 cm of it off the table, does it makes any sound? If there is no sound, look for the reason why it is so?
Answer:
No, the ruler vibrates very slowly, which has frequency which is not audible.

Question 4.
What would be the difference perceived between hearing only two pupils in the class talking to each other and all the children talking to one another at the same time?
Answer:

When two pupils talk to each other, the sounds of two frequencies produced can be heard clearly.
When all the children talk to one another sounds of many frequencies produced can not be heard clearly.
Sound level will be more creating loud noise.

7th Std Science Questions And Answers:

Simple Machines Class 6 Science Chapter 12 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 12 Simple Machines Notes, Textbook Exercise Important Questions and Answers.

Std 6 Science Chapter 12 Simple Machines Question Answer Maharashtra Board

Class 6 Science Chapter 12 Simple Machines Question Answer Maharashtra Board

1. Classify the following as a lever, a pulley and an inclined plane:
(A wedge, a needle, a staircase, a slide, the wheel of a flagpole, nutcrackers, scissors, an opener, an axe, a crane, a knife)

Question a.
Classify the following as a lever, a pulley and an inclined plane:
(A wedge, a needle, a staircase, a slide, the wheel of a flagpole, nutcrackers, scissors, an opener, an axe, a crane, a knife)
Answer:

Inclined plane	Pulley	Lever
Wedge	Wheel of flagpole	Nutcracker
Needle	Crane	Scissors
Staircase		Opener
Slide
Axe
Knife.

2. Fill in the blanks using the proper word and complete the statements.

Question a.
The ………….. in the centre, the ………….. on one side and the on the ………….. other side make a lever of the first order.
Answer:
Fulcrum, load and effort

Question b.
The ………….. in the centre, the ………….. on one side and the ………….. on the other side make a lever of the second order.
Answer:
Load, fulcrum, effort

Question c.
The ………….. in the centre, the ………….. on one side and the ………….. on the other side make a lever of the third order.
Answer:
Effort, fulcrum, load

3. Which machines will you use to do the following work? Write their types.

Question a.
To remove the lid of a tin. Opener Lever of the second order
Answer:

Work: To remove the lid of a tin.
Machine: Opener
Machine: Lever of the second order

Question b.
To lift bricks to the top of a tall building Crane Complex machine
Answer:

Work: To lift bricks to the top of a tall building
Machine: Crane
Machine: Complex machine

Question c.
To cut vegetable Knife Wedge – Simple machine
Answer:

Work: To cut vegetable
Machine: Knife
Machine: Wedge – Simple machine

Question d.
To draw water from a well Pulley Simple machine
Answer:

Work: To draw water from a well
Machine: Pulley
Machine: Simple machine

Question e.
To hold a papad for roasting it. A pair of tongs Lever of the third order
Answer:

Work: To hold a papad for roasting it.
Machine: A pair of tongs
Machine: Lever of the third order

4. Write the answers to the following questions in your own words.

Question a.
What is meant by a simple machine?
Answer:

Machines which have only one or two parts and a simple and easy structure are simple machines.
Example: the bottle opener, nail cutter.
Simple machines can be handled easily.
We use many simple machines in our day to day life.

Question b.
Mention the advantages of using a machine.
Answer:

Machines, simple or complex, are used to get more work done in less time and with less effort.
Machines are used to accomplish certain tasks more easily.
Use of simple or complex machines depends upon the task to be carried out and the time and the efforts required to do it.

Question c.
What is meant by a complex machine?
Answer:

Complex machines have many parts which carry out many processes for completing a task.
For this purpose the parts are joined to one another.
Therefore, these machines are called complex machines.
Some of the parts of such complex machines are actually simple machines.
The structure of complex machine is complicated.

Question d.
What is a lever? How is the order of the lever determined?
Answer:

Lever is a simple machine made up of 3 parts: Load, effort and fulcrum.
Order of the lever are determined on the position of the effort, the fulcrum and the load.

5. Why is this so?

Question a.
Traveller’s bags have wheels.
Answer:

Combination of wheel and axle is a simple machine.
When the axle starts rotating due to force applied, the wheel fitted to it also starts rotating.
This makes easier for travellers to carry heavy load.
Instead of lifting heavy bag, to drawing it on wheels require less energy. Therefore, traveller’s bag have wheels.

Question b.
Machines have to be maintained.
Answer:

Parts of machines rub against one another when they are used.
Soiled, dusty parts create more friction. Some parts are affected by the weather, rust and corrosion.
Machines get damaged or become useless due to such wear and tear. Hence to avoid this, machines should be maintained properly to keep them in good working condition.

Question c.
A bicycle is said to be a complex machine.
Answer:

Bicycle has a complicated structure.
Bicycle has many parts which carry out many processes for completing a task.
Many parts of bicycle such as pedals, wheels, axle, handle are actually simple machines.
The parts of a bicycle are joined to one another – making it a complex machine.

6. Name the levers mentioned in the following passage. Identify the fulcrum, load and effort of each and say which type of lever it is.

Ravi and Savita sit on a sea-saw in a garden. In the mean time, a gardener is trimming trees in the garden. He puts the leaves and other garbage in the wheelbarrow. Later, Ravi gets thirsty and he buys lemon sherbet. The sherbet seller cuts the lemon and squeezes it using a lemon squeezer. He puts small pieces of ice in the glass with the help of the tongs.

Question a.
Name the levers mentioned in the following passage. Identify the fulcrum, load and effort of each and say which type of lever it is.

See – saw – lever of the first order.
Load – fulcrum – effort.
Wheelbarrow – lever of the second order.
Fulcrum – load – effort.
Lemon squeezers – lever of the second order.
Fulcrum – load – effort.
Tongs – lever of the third order.
Fulcrum – effort – load.

Activity:

Question 1.
Make a list of the various machines used in your home and neighborhood and write their types.

Question 2.
Go to a bicycle repair shop, observe how a bicycle is repaired, and note down the information.

Class 6 Science Chapter 12 Simple Machines Important Questions and Answers

Fill in the blanks.

Question 1.
Simple machines can be handled ………….. .
Answer:
easily

Question 2.
The structure of complex machine is ………….. .
Answer:
complicated

Question 3.
The more gradual the the ………….. lesser is the we bear. But, such an inclined plane is ………….. .
Answer:
slope, weight, longer

Question 4.
The steeper the ………….. , the ………….. is the inclined plane. But we have to bear a …………. weight.
Answer:
slope, shorter, greater

Question 5.
A screw is like a rolled up inclined plane made of an ………….. strip.
Answer:
iron

Question 6.
A wedge is used for ………… an object into two pieces or to ………….. the objects stuck together.
Answer:
breaking, separate

Question 7.
A farmer uses a strong …………. to remove the big stone bogged down in the farm.
Answer:
crow-bar

Question 8.
A device with a grooved wheel and thread designed to lift weights is called a …………. .
Answer:
pulley

Question 9.
When we use a pulley, force is applied in the downward direction for lifting the weight in an …………. direction.
Answer:
upward

Question 10.
Combination of an axle and a wheel is a …………. machine.
Answer:
simple

Question 11.
A needle and a nail are also kind of …………. .
Answer:
wedge

Question 12.
Machines are covered when not in use to prevent …………. settling on them.
Answer:
dust

Question 13.
In Archimedes’ screw, the pipe was placed at an angle of …………. with one end inside the …………. and the rod resting on a …………. .
Answer:
45°, water, flat surface.

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
1. Pair of Scissors	a. Third order of lever
2. Tongs	b. Second order of lever
3. Opener	c. First order of lever

Answer:

Column ‘A’	Column ‘B’
1. Pair of Scissors	c. First order of lever
2. Tongs	a. Third order of lever
3. Opener	b. Second order of lever

Question 2.

Column ‘A’	Column ‘B’
1. Inclined plane	a. Needle
2. Pulley	b. Screw
3. Wedge	c. Crane

Answer:

Column ‘A’	Column ‘B’
1. Inclined plane	b. Screw
2. Pulley	c. Crane
3. Wedge	a. Needle

State whether the following statements are ‘true’ or ‘false’.

Question 1.
Lever helps big vehicle to climb up and down the mountain easily.
Answer:
False

Question 2.
Combination of wheel and axle is a simple machine.
Answer:
True

Question 3.
In pulley, force can be applied in upward direction.
Answer:
False

Question 4.
Screw is an example of wedge.
Answer:
False

Question 5.
In Archimedes screw, the rod rests on flat surface.
Answer:
True

Question 6.
A slanting plank is used to lift a weight.
Answer:
True

Question 7.
A winding road or ghat is an example of lever of first order.
Answer:
False

Answer the following questions in one sentence.

Question 1.
What is a machine?
Answer:
Devices which are used to get more work done in less time and less effort are called machines.

Question 2.
What is a simple machine?
Answer:
Machines which have only one or two parts and a simple and easy structure are called simple machines.

Question 3.
What is a complex machine?
Answer:
Some machines have many parts and they carry out many processes for completing a task. For this purpose, the parts are joined to each other. They are called complex machines.

Question 4.
List the properties of simple machines.
Answer:
Properties of simple machine are:

They are made up of only one or two parts.
They have a simple and easy structure.
They can be handled easily.
There are less chances of simple machines breaking down or getting damaged.

Question 5.
List properties of complex machines.
Answer:
Properties of complex machine are:

These machines have many parts to carry out many processes.
The parts are joined to one another.
The structure of complex machines is complicated.
Some parts of complex machines are actually simple machines.

Question 6.
What is an inclined plane?
Answer:
A slanting plank which is used to lift a weight on which we bear less weight and lifting becomes easier is an inclined plane.

Question 7.
What is a screw?
Answer:
A screw is like a rolled up inclined plane made up of iron strip.

Question 8.
What is a wedge?
Answer:
A wedge is used for breaking an object into two pieces or to separate objects stuck together.

Question 9.
State examples of wedges.
Answer:
An axle, a knife, a chisel, a needle and a nail are different kinds of wedges.

Question 10.
What is a lever?
Answer:
A lever is a machine made up of 3 parts: effort, load and fulcrum.

Question 11.
What is a fulcrum?
Answer:
The support at which the rod of a lever is rested is called fulcrum of a lever. The lever rotates about the fulcrum.

Question 12.
What is a load?
Answer:
The weight lifted by a lever or the force against which the lever acts is called a load.

Question 13.
What is a load arm?
Answer:
The arm of the lever from the fulcrum to the load is called a load arm.

Question 14.
What is an effort?
Answer:
The force applied on the other end of the rod to lift the load is called an effort.

Question 15.
What is an effort arm?
Answer:
The part of the lever from the fulcrum to the effort is called an effort arm.

Question 16.
What is lever of the first order?
Answer:
The fulcrum is in the centre, the load is at one end while effort is at other end.

Question 17.
What is lever of the second order?
Answer:
The load is in the centre, the fulcrum on one side, and the effort on the other side.

Question 18.
What is lever of the third order?
Answer:
The effort is in the centre, the fulcrum on one side, and the load on the other side.

Question 19.
What is a pulley?
Answer:
A pulley is a device with a grooved wheel and thread designed to lift weights.

Question 2.
How does a pulley help us?
Answer:
If we use a pulley, force can be applied in the downward direction for lifting the weight in an upward direction. It is convenient and easy.

Give scientific reasons:

Question 1.
We use many simple machines in our day-to-day life.
Answer:
Simple machines can be handled easily and there are less chances of these machines breaking down or getting damaged. Hence, we use many simple machines in our day-to-day life.

Question 2.
Less force is required to fit a screw than to hammer a nail.
Answer:

A screw is like a rolled-up inclined plane of an iron strip.
When a screw is fitted in wood it goes in as if it is going down an inclined plane.
Therefore, less force is required to fit a screw than hammer a nail.

Question 3.
Big vehicles easily climb up and down the mountains than a pathway.
Answer:
A winding road or ghat that goes up a mountain is like an inclined plane wrapped around the mountain. It helps big vehicles to climb, up and down the mountain easily.

Question 4.
Oil or lubricant is released between parts of machine.
Answer:
Oil or lubricant is released between parts that rub against each other so that there is less friction between them and wearing is reduced.

Question 5.
Machines are covered when not in use.
Answer:
Machines are covered when not in use to prevent dust settling on them.

Question 6.
How are machines protected from the effect of weather?
Answer:
To prevent the effect of weather, metallic parts in a machine are painted externally and the machines are always kept dry.

Draw the neat and labelled diagram of following:

Question 1.
The screw as an inclined plane.
Answer:

Question 2.
Archimedes’ screw
Answer:

Observe the following diagram and identify the order of lever.

Question 1.
Removing the lid.
Answer:

Question 2.
Picking up an object.
Answer:

Question 3.
Lifting a paper weight.

Answer:

Lever of the second order
lever of third order
Level of first order.

Answer each of the question in brief:

Question 1.
With the help of the diagram explain lever of the 1st, 2nd, 3rd order.
Answer:
1. Lever of the First order: The fulcrum is in the centre, the load is at one end, while the effort is at the other end. e.g. scissors

2. Lever of the Second order: The load is in the centre, the fulcrum on one side, and the effort on the other side. e.g. lid opener

3. Lever of the Third order: The effort is in the centre, the fulcrum on one side, and the load on the other side. e.g. Tongs

Question 2.
How can machines be maintained?
Answer:

To maintain machines, all its parts are wiped clean.
Oil or lubricant is released between parts that rub against each other.
Machines are covered, painted externally and always kept dry.

Question 3.
What is an inclined plane? Explain longer and shorter inclined plane.
Answer:

A slanting plank used to lift a weight, is called an inclined plane. Because of inclined plane we will experience less weight and weight lifting become easier.
Longer inclined plane: When the inclined plane is longer, the slope is more gradual and lesser is the weight we bear.
Shorter inclined plane: When the inclined plane is shorter, the slope is steeper and greater is the weight we bear.

Question 6.
Explain the working of a giant wheel.
Answer:

The giant wheel is fitted to a rod at its centre. This rod is called an axle.
When the axle starts rotating with the help of electricity the wheel fitted to it starts rotating.
This combination of an axle and a wheel is a simple machine.

Observe and discuss:

Question 1.
Name the devices and discuss how they help.

Answer:

Needle and thread – Stitching of clothes
Wheelbarrow – To carry materials.
Opener – To open the lids of bottles.
Pulley – To lift bucket
Nail cutter – To cut nails
Axe – To cut wood into small pieces

Can you tell?

Question 1.
Observe the machines shown in the following pictures. For what purposes are they used? Can you name some other machines of this kind?

Answer:

Mixer grinder – To grind the foodstuffs
Scooter – To ride and reach places
Bicycle – To ride and reach places
Sewing machine – To stitch clothes
Wheel chair – Specially designed for handicapped patients to move around.

Question 2.
Compare the pathway and a road, available to climb the mountain, the time and strength and your convenience, required to reach the mountain top.
Answer:
We can reach the mountain top by climbing the pathway early than by the road. The time required is less but the strength required is more. The road is easy to walk and more time consuming.

Question 3.
If the point of a needle or the edge of a knife become blunt, then the needle does not penetrate the cloth and the knife does not cut into the fruit. Why is this so?
Answer:
The tip of the needle or the edge of a knife becomes blunt due to regular use. Both the knife and the needle lose their sharpness.

Use your brain power!

Question 1.
Which task can be done using a lever?
Answer:
Task such as using a nut cracker, cutting paper with scissors, can be done using a lever.

Question 2.
Some machines we use in our day to day life are shown in picture. What is the type in each of these?

Answer:

Wheelbarrow – Lever of the third order
Pair of tongs – Lever of the first order
See – saw – Lever of the first
order Cutter – Lever of the second lever
Pair of Scissors – Lever of the first order.

Question 3.
When the pedal of the bicycle is rotating, the wheel starts rotating. How does this happen?
Answer:
Pedals of the bicycle are connected to the wheels through the axle, when the axle starts rotating, the wheels also start rotating.

Question 4.
Examples of pulley.
Answer:

A simple pulley is used to hoist a flag, to draw water from a well.
The crane which is used to lift heavy loads is an example of application of pulleys and levers working together.

6th Std Science Questions And Answers:

Diversity in Living Things and their Classification Class 6 Science Chapter 3 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 3 Diversity in Living Things and their Classification Notes, Textbook Exercise Important Questions and Answers.

Std 6 Science Chapter 3 Diversity in Living Things and their Classification Question Answer Maharashtra Board

Class 6 Science Chapter 3 Diversity in Living Things and their Classification Question Answer Maharashtra Board

1. Match the pairs.

diversity in living things and their classification class 6 exercise Question 1.

Column ‘A’	Column ‘B’
1. Amphibians	a. A monkey
2. Vertebrates	b. A snake
3. With scales	c. A frog

Answer:

Column ‘A’	Column ‘B’
1. Amphibians	c. A frog
2. Vertebrates	a. A monkey
3. With scales	b. A snake

2. Who is the odd one out?

Question a.
Fungus, mushroom, chrysanthemum, spirogyra
Answer:
Chrysanthemum (only flowering plants)
or
Spirogyra (only aquatic plant)

Question b.
Mango, banyan, palm, chickpea
Answer:
Chickpea (shrub, others are not)
or
Palm (tall tree without any branches, others have branches)

Question c.
Grape, orange, lemon, hibiscus
Answer:
Grape (only creeper, others are not)
or
Hibiscus (flower, others are fruits)

Question d.
Sunflower, banyan, jowar, bajra
Answer:
Banyan (perinnial, others are not)

Question e.
Guava, radish, carrot, beetroot
Answer:
Gauva (fruit, others are roots)

Question f.
Deer, fish, man, worms
Answer:
Worms (invertebrate, others are not)
or
Fish (aquatic animal, others are terristrial animals

3. What is the difference?

Question a.
Flowering plant and Non-flowering plant
Answer:

Flowering plant	Non-flowering plant
1. Plants that bear flowers are called flowering plants.	1. Plants that do not bear flowers are called nonflowering plants.
2. They have roots, stems and leaves.	2. They may not have roots, stems or leaves.
e.g. Rose, sunflower, lotus	e.g. Pine, fern, algae

Question b.
A Tree and a Shrub
Answer:

Tree	Shrub
1. They have branches at some height above the ground.	1. They give out branches close to the ground.
2. They grow very tall compared to shrubs.	2. They grow upto 2 to 3 metres in height.
3. They have strong and hard stems.	3. They have thick hard stems.
e.g. Mango tree, banyan tree	e.g. Hibiscus, oleander

Question c.
Vertebrates and Invertebrates
Answer:

Vertebrates	Invertebrates
1. They have vertebral column.	1. They do not have vertebral column.
2. The brain is well developed.	2. The brain if present may not be developed.
e.g. Human, dog, fishes etc.	e.g. earthworm, insects etc.

4. True or false?

Question a.
The snail is an aquatic animal.
Answer:
False

Question b.
Amphibians can live in air and in water.
Answer:
False

Question c.
The function of the brain is well developed in vertebrate.
Answer:
True

Question d.
The amoeba is a multicellular animal.
Answer:
False

5. Write two names of each.

Question a.
A flowering plant
Answer:
Rose, hibiscus

Question b.
A non-flowering plant
Answer:
Fern, algae

Question c.
A tree
Answer:
Mango, banyan

Question d.
A shrub
Answer:
Oleander, hibiscus

Question e.
A creeper
Answer:
Pumpkin, watermelon

Question f.
An annual plant
Answer:
Jowar, sunflower

Question g.
A biennial plant
Answer:
Carrot, beetroot

Question h.
A perennial plant
Answer:
Mango, gulmohar

6. Write answers to the following.

Question a.
What are the parts of a plant?
Answer:
The parts of a plant are: root, stem, leaves, flowers, fruit and seed.

Question b.
What are the functions of root?
Answer:
The functions of root are:

The root hold the soil firmly and anchor the plant.
They absorb water, salt and minerals from the soil and transport it to stem.
Some roots store food. e.g. Carrot, radish.

Question c.
Why is it necessary to classify living things?
Answer:

There is a great diversity in living things- both plants and animals on the earth.
In order to identify them and to study their characteristics, systematic classification is necessary.

Question d.
What are the criteria used to classify living things?
Answer:
Following are the criteria used to classify living things:
a. Plants:

Mode of nutrition.
Similarities and differences in structure.
Presence of flowers or not.
Period of life cycles.
Habitat.

b. Animals:

Cell structure.
Presence of vertebral column.
Method of reproduction.
Habitat.

Question e.
Tell some characteristics of creepers.
Answer:
The characteristics of creepers are:

The stem of a creeper is very flexible, soft and green and need support to climb.
Some climbers spread on the ground, e.g. Pumpkin
Some have aerial roots, e.g. Money plant
Some climbers develop tendrils, e.g. Cucumber

Question f.
Explain the characteristics of herbs with examples.
Answer:

Herbs grow 1 to 1.5 m tall.
Their stem is green and quite flexible.
They may live for a few months or upto two years, e.g. Tulsi, oregano, etc.

Question g.
How is the body of animals protected?
Answer:
Body of animals are protected by special covering such as skins, feathers, scales, hair fur, etc.

Question h.
On the basis of which criteria will you classify plants and animals?
Answer:

7. Draw figures.

Question a.
Draw the figure of a plant to show the parts, namely, the root, stem and leaves in it.
Answer:

Activity:

Question 1.
Visit a plant nursery and classify the plants there.

Question 2.
Visit a zoo and obtain information about the diversity in animals.

Question 3.
Write an essay on diversity in plants.

Question 4.
Collect seeds of various plants during summer and throw them in open spaces (fallow land, moorland, hill, etc.) during the rainy season.

Class 6 Science Chapter 3 Diversity in Living Things and their Classification Important Questions and Answers

Fill in the blanks:

Question 1.
Plants that can prepare their own food are called ………….. plants.
Answer:
autotrophic

Question 2.
Pitcher plants are ………….. .
Answer:
insectivorous

Question 3.
The ………….. is an important means of reproduction.
Answer:
flower

Question 4.
Animals that lay eggs are ………….. animals.
Answer:
oviparous

Question 5.
Animals that can live on land as well as water are called ………….. .
Answer:
amphibians

Choose the correct alternative:

Question 1.
The ………….. is a perennial.
(a) beetroot
(b) gulmohar
(c) grass
Answer:
(b) gulmohar

Question 2.
The sunflower is a / an ………….. plant.
(a) annual
(b) biennial
(c) perennial
Answer:
(a) annual

Question 3.
Cactus is a ………….. plant.
(a) land
(b) water
(c) desert
Answer:
(c) desert

Question 4.
The …………….. is a unicellular animal.
(a) cockroach
(b) snail
(c) paramoecium
Answer:
(c) paramoecium

Question 5.
Hen is a …………….. animal.
(a) oviparous
(b) viviparous
(c) none of above
Answer:
(b) oviparous

Question 6.
Earthworm is a / an ……………. animal.
(a) vertebrate
(b) invertebrate
(c) unicellular
Answer:
(b) invertebrate

True or False:

Question 1.
The pods of beans and peas are actually fruits.
Answer:
True

Question 2.
Fungus is heterotrophic.
Answer:
True

Write two names of each.

Question 1.
An invertebrate animal
Answer:
Earthworm, cockroach

Question 2.
An oviparous animal.
Answer:
Hen, sparrow

Distinguish between:

Question 1.
Autotrophic plant and Heterotrophic plant
Answer:

Autotrophic plant	Heterotrophic plant
1. They can produce their own food.	1. They cannot produce their own food. They depend on other things for their food.
2. They are green in colour.	2. They are nongreen in colour.
e.g. Periwinkle, pomegranate etc.	e.g. Dodder, loranthus etc

Classify as directed.

Question 1.
Into annual, biennial, perennial
Sunflower, carrot, bajra, mango, jowar, oleander, beetroot, coconut
Answer:

Annual	Biennial	Perennial
Sunflower	Carrot	Mango
bajra	beetroot	oleander
jowar		coconut

Question 2.
Into vertebrates and invertebrates
Fish, cat, earthworm, snail, hen, cockroach
Answer:

Vertebrates	Invertebrates
Fish	Earthworm
cat	snail
hen	cockroach

Define.

Class 6 Science Chapter 3 Diversity In Living Things and Their Classification Question 1.
Unicellular animal
Answer:
Animals which have a single cell body performing all functions, are called unicellular animals, e.g. Amoeba

Diversity In Living Things And Their Classification Exercise Question 2.
Multicellular animals
Answer:
Animals which have many cells in their body, are called multicellular animals, e.g. Cat

Diversity In Living Things and Their Classification Question 3.
Vertebrates
Answer:
Animals with vertebral column are called vertebrates, e.g. Man

Question 4.
Invertebrate animals
Answer:
Animals without vertebrate column are called invertebrate animals, e.g. Earthworm

Question 5.
Oviparous animals
Answer:
Animals which lay eggs and hatch them are called oviparous animals, e.g. Hen

Question 6.
Viviparous animals
Answer:
Animals which give birth to their young ones are called viviparous animals, e.g. Dog

Answer the following:

Question 1.
Give the functions of:
Answer:
a. Stem:
1. The stem gives support to the other parts of the plant.
2. The stem carries out the function of production, conduction and storage of the food.
3. In some cases it stores food.
b. Leaves: They play an important role in the production of food.
c. Flowers: The flowers are reproductive organ of plant.
d. Fruits: Fruits have seeds which give rise to new plant.
e. Seeds: From the seeds arise new plants.

Answer the following in short.

Question 1.
What type of plants are toolstools and mushrooms?
Answer:
Toolstools and mushrooms are heterotrophs.

Question 2.
What type of plant is a fig?
Answer:
Fig is a tree.

Question 3.
Do ferns, algae and money plant bear flowers?
Answer:
Ferns, algae and money plants do not bear flowers. They are non-flowering plants.

Question 4.
Which is the largest flower and where is it found?
Answer:
Rafflesia Arnoldi is the world’s largest flower. It is found in Indonesia.

Question 5.
Where does pomegranate grow?
Answer:
Pomegranate is a shrub which grows on land in soil.

Question 6.
Where do bulrushes and railroad creepers grow?
Answer:
Bulrushes is a water plant and railroad creepers grow along the ground.

Question 7.
Where does lotus grow?
Answer:
Lotus grows in water.

Question 8.
Where does the dodder plant grow?
Answer:
Dodder is a parasitic plant and grows on other plants.

Question 9.
Why does water hyacinth float?
Answer:
The stem of water hyacinth is filled with air and its leaves are specially modified, which helps it to float in water.

Question 10.
Why is the stem of a cactus plant fleshy?
Answer:
Cactus is a desert plant. As there is a shortage of water, cactus stores water in its stem and hence, stem of cactus is fleshy.

Question 11.
Which spheres of the earth do living things exist?
Answer:
Living things exists in all three spheres of earth, i.e. Atmosphere, lithosphere and hydrosphere.

Question 12.
Are the plants and animals that you have seen all alike?
Answer:
No. They are all of different types.

Question 13.
What are the similarities between a mango, a banyan and a tamarind tree?
Answer:
They are tall, big and perennial plants.

Question 14.
What are the similarities between the hibiscus, oleander and lantana plants?
Answer:
They are shorter and smaller than trees.

Question 15.
What are the similarities between fenugreek and periwinkle plants?
Answer:
They are smaller and shorter than trees and shrubs.

Question 16.
Have you seen vines like the pumpkin, the railroad creeper, kavali, watermelon or the grapvine? How do they grow?
Answer:
They have very soft, green and flexible stem. They grow with the help of a support.

Question 17.
For how many years do crops like bajra, wheat, corn, radish, marigold live?
Answer:
They live for about one year.

Question 18.
To which part of plants are butterflies and insects attracted?
Answer:
Butterflies and insects are attracted towards the flower of the plants.

Question 19.
What is the chain of bones in the centre of our back called?
Answer:
A vertibral column.

6th Std Science Questions And Answers:

Measurement of Physical Quantities Class 7 Science Chapter 6 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 6 Measurement of Physical Quantities Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 6 Measurement of Physical Quantities Question Answer Maharashtra Board

Class 7 Science Chapter 6 Measurement of Physical Quantities Question Answer Maharashtra Board

1. Write answers to the following questions in your own words:

Question a.
Why is the weight of the same object different on different planets?
Answer:
The weight of the same object is different on different planets because weight depends on the gravitational force of the planet and gravitational force on every planet is different so the weight also differs from planet to planet.

Question b.
What precautions will you take to make accurate measurements in day-to-day affairs?
Answer:
Following precautions will be taken to make accurate measurements in day to day affairs:

The balance should carry the stamp of standardisation by the department of weights and measures.
Balance should be stable and the pointer of the balance should be upright.
The underside of the pan should not be tampered with any other weight or layers of other metal.
The weight should be made of metal.

Question c.
What is the difference between mass and weight?
Answer:

Mass	Weight
1. The amount of matter present in a substance is called mass.	1. The gravitational force that acts on this mass is called its weight.
2. It is a scalar quantity.	2. It is a vector quantity.
3. Mass remains same everywhere on the earth.	3. Weight changes from place to place on the ‘ earth.

2. Who is my companion?

Class 7 Science Chapter 6 Measurement Of Physical Quantities Exercise Question 1.

Column ‘A’	Column ‘B’
1. Velocity	a. Litre
2. Area	b. Kilogram
3. Volume	c. metre/second
4. Mass	d. kilogram/cubic metre
5. Density	e. square metre

Answer:

Column ‘A’	Column ‘B’
1. Velocity	c. metre/second
2. Area	e. square metre
3. Volume	a. Litre
4. Mass	b. Kilogram
5. Density	d. kilogram/cubic metre

3. Explain giving examples.

Question a.
Scalar quantity:
Answer:
A quantity that can be completely expressed by its magnitude alone is called a scalar quantity, e.g. length, breadth, area, mass, temperature, density, time, work. In all these examples a value with a unit is used to express quantities. Thus, we say that the length of a tunnel is 2 km.

Question b.
Vector quantity:
Answer:
The quantity that is expressed completely only.’ v when magnitude and direction are both given is called a vector quantity. Displacement, velocity are vector quantities e.g. a displacement of 20 km towards north, the aeroplane flying at a velocity of 500 km/hr towards Mumbai.

4. Explain, giving examples, the errors that occur while making measurements.

Question a.
Explain, giving examples, the errors that occur while making measurements.
Answer:
Major causes of errors in measurement are:

Not using the appropriate device.
Not using the device properly.

Example: While buying things at grocery shops and the vegetable market remember to look out for the following:

The balance should carry the stamp of standardisation by the department of weights and measures.
Balance should be stable. The pointer of the balance should be upright.
No changes should be done on the underside of the pan of the balance.
Weight should be made up of metals and it has to be standardized.

5. Give reasons:

Question a.
It is not proper to measure quantities by using body parts as units.
Answer:
It is not proper to measure quantities by using body parts as units because length of the body parts changes from person to person, so accurate measurement can not be found with the body parts as units.

Question b.
It is necessary to get the weights and measures standardized at regular intervals.
Answer:
It is necessary to get the weights and measures standardized at regular intervals because of that accurate weight and measurement can be taken. Errors will be avoided.

6. Explain the need for accurate measurement and the devices to be used for that.

Question a.
Explain the need for accurate measurement and the devices to be used for that.
Answer:

Measurement of substances that are precious or of great importance and used in very small quantities is done meticulously and accurately.
Due to advancements in technology, devices that measure very small magnitudes of quantities like distance, mass, time and temperature are available now.
e.g. distance and time in connection with very important sports competitions, mass of gold, body temperature etc.
Devices to be used for this are thermometer, digital balance (Analytical balance) etc.

Project:

Class 7 Science Chapter 6 Measurement Of Physical Quantities Question 1.
Collect information about various physical quantities used in day-to-day life and the devices used for their measurement.

Class 7 Science Chapter 6 Measurement of Physical Quantities Important Questions and Answers

Fill in the blanks:

Std 7 Science Chapter 6 Measurement Of Physical Quantities Question 1.
The amount of matter present in a substance is called ………………. .
Answer:
mass

Measurement Of Physical Quantities Class 7 Exercise Question 2.
…………. is the qualitative measure of the inertia of an object.
Answer:
mass

6. Measurement Of Physical Quantities Question 3.
The larger the mass, the ……………. is the inertia.
Answer:
greater

6.Measurement Of Physical Quantities Question 4.
Mass is a …………… quantity.
Answer:
scalar

Physical Quantities And Measurement Class 7 Question 5.
…………… does not change from place to place anywhere in the world.
Answer:
mass

Measurement Of Physical Quantities Class 7 Question 6.
The gravitational force that acts on a mass is called its ……………. .
Answer:
weight

6 Measurement Of Physical Quantities Question 7.
Wright is a …………… quantity.
Answer:
vector

Question 8.
System International (SI) is also called ………….. .
Answer:
metric system

Question 9.
In Egypt in ancient times, the distance from a man’s elbow to the tip of his middle finger was called a ………… .
Answer:
cubit

Question 10.
Gold was weighed in a unit called …………… .
Answer:
gun

Who is my companion?

Question 1.

Column ‘A’	Column ‘B’
1. Gold	a. Hour glass
2. Time	b. Vector
3. Distance	c. Gunj
4. Weight	d. Cubit

Answer

Column ‘A’	Column ‘B’
1. Gold	c. Gunj
2. Time	a. Hour glass
3. Distance	d. Cubit
4. Weight	b. Vector

Say whether true or false. Correct and rewrite the false statements:

Question 1.
The standards of the six fundamental units are kept in the National Physical Laboratory at New Delhi.
Answer:
True

Question 2.
Matter has a natural tendency to resist a change in its state, which is called inertia.
Answer:
True

Question 3.
Weight and mass are both equal quantities.
Answer:
False. Weight and mass are both different quantities

Question 4.
Work is a vector quantity.
Answer:
False. Work is a scalar quantity

Question 5.
Velocity is a scalar quantity.
Answer:
False. Velocity is a vector quantity

Question 6.
Unit of time in both the systems is second.
Answer:
True

Question 7.
Unit of mass in C.G.S. system is kilogram
Answer:
False. Unit of mass in C.G.S. system is gram

Question 8.
Symbol of unit of second is sec.
Answer:
False. Symbol of unit of second is ‘s’

Question 9.
1 cubic foot means 28.317 ml
Answer:
False. 1 cubic foot means 28.317 litres.

Question 10.
Vector quantity requires magnitude only.
Answer:
False. Vector quantity required magnitude and direction both.

Give scientific reasons:

Question 1.
Weight of our body on the moon is less than that on the earth.
Answer:

Gravitational power of moon is less than the earth.
Weight depends on the gravitational power of that place.
Since the gravitational power of the moon is less than that of the earth, the weight on moon is less than that on the earth.

Question 2.
Mass is a scalar quantity
Answer:
Mass is a scalar quantity because it can be completely expressed by its magnitude alone, so it is scalar quantity.

Question 3.
Weight is a vector quantity.
Answer:
Weight can be expressed completely only when magnitude and direction are both given so weight is a vector quantity.

Distinguish between the following:

Question 1.
Scalar quantity and Vector quantity
Answer:

Scalar quantity	Vector quantity
1. A quantity that can be completely expressed by its magnitude alone is called a scalar quantity.	1. The quantity that is expressed completely only when magnitude and direction are both given is called a vector quantity.
2. e.g. mass, length, area, breadth, density, time, work etc.	2. e.g. velocity displacement

Question 2.
M.K.S. system and C.G.S. system
Answer:

M.K.S. system	C.G.S. system
1. In this system distance is measured in metres, mass in kilograms and time in seconds.	1. In this system distance is measured in centimetres, mass in grams and time in seconds.
2. e.g. Unit of velocity is m/sec, Unit of area is square metre.	2. e.g. Unit of velocity is cm/sec, Unit of area is square centimetre.

Define the following:

Mass: The amount of matter present in a substance is called mass.
Inertia: Matter has a natural tendency to resist a change in its state, which is called Inertia.
Weight: The gravitational force that acts on the mass is called its weight.
Physical Quantities: The quantities in day to day life which can be measured are called physical quantities.
Standardization: The process of checking things against a standard measure from time to time is called standardization.

Write answers to the following questions in your own words.

Question 1.
What is an atomic clock?
Answer:
An extremely accurate type of clock which is regulated by the vibrations of an atomic or molecular system such as caesium atom or ammonia is called atomic clock. It is used to maintain standard times of countries accurately.

Answer the following questions:

Question 1.
Why would the weight of an object be; maximum at the poles and minimum at the equator?
Answer:

The gravitational force that acts on the mass is called the weight.
The earth is not exactly spherical, it flattens at the poles.
As the distance increases the gravitational force decreases.
Therefore due to reduced distance at the poles compared to the equator, the weight is maximum at the poles than equator.

Question 2.
Why is the weight of an object at a high altitude less than its weight at the sea-level?
Answer:

The gravitational force that acts on the mass is called the weight.
The gravitational force is always inversely proportional to the distance.
So as the distance increases between the earth and the object, the gravitational force decreases.
The gravitational force by which the earth attracts an object towards its centre is called weight.
The weight at the sea-level is higher than at higher altitude, as the object is at a greater distance at higher altitudes compared to sea-level.

7th Std Science Questions And Answers:

Sound Class 6 Science Chapter 13 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 13 Sound Notes, Textbook Exercise Important Questions and Answers.

Std 6 Science Chapter 13 Sound Question Answer Maharashtra Board

Class 6 Science Chapter 13 Sound Question Answer Maharashtra Board

1. Fill in the blanks with the proper words.

Question a.
The propagation of sound does not occur through a ………….. .
Answer:
vacuum

Question b.
Noise pollution is a …………… issue.
Answer:
social/serious

Question c.
The sound which is disagreeable to our ears is called …………… .
Answer:
noise

Question d.
Noise has adverse effects on our …………….. .
Answer:
health

2. What should we do?

Question a.
The silencer of a motorcycle is broken.
Answer:

If the silencer of a motorcycle is broken, vehicle should be immediately taken to the garage for repair.
If silencer is not maintained properly, it will continue making loud noise on the road while in motion, resulting in increasing noise pollution.

Question b.
A factory in the surrounding is producing continuous loud noise.
Answer:
Factories should be located at a proper distance away from residential areas. Authorities should be contacted who will control the decibel level.

3. Write the answers in your own words.

Question a.
What is meant by vibration?
Answer:
Vibration of an object is necessary for the production of sound. As long as the object vibrates, the sound is heard. When the vibration stops, the sound also stops.

Question b.
Explain with the help of practical examples how sound is propagated through solids.

Answer:

Singing
Chirping of birds
Bursting of crackers
Whispering
Whistling
Flute
Honking
Dog barking

Question c.
What is meant by noise pollution?
Answer:
Continuous noise which has ill effects is called noise pollution.

Question d.
What measures will you take to control noise pollution?
Answer:
Measures for preventing noise pollution:

As far as possible, we should avoid blowing horns.
The volume of the TV or radio in the house should be restricted to those watching the programmes.
Vehicles should be maintained properly to reduce the unnecessary sounds they produce.
Factories, airports, railway stations and bus stands should be located at the proper distance away from residential area.
Planting of trees helps reduce noise as trees act as a natural barrier.

4. Complete the table.

Question a.

Answer:

Nature of sound	Unpleasant	Pleasant
1. Speaking		✓
2. Whispering		✓
3. Aeroplane Sounds	✓
4. Horns of Vehicles	✓
5. Railway Engine	✓
6. Rustling of leaves		✓
7. Neighing of a horse	✓
8. Ticking of a clock		✓

Project:

Question 1.
Prepare a list of the harsh sounds mheard near your house. Write about those sounds which produce noise pollution.

Question 2.
Collect information about places where loud noise is prohibited and discuss why it is so.

Class 6 Science Chapter 13 Sound Important Questions and Answers

Fill in the blanks:

Question 1.
Some sounds are ……………… and are heard easily.
Answer:
loud

Question 2.
Some sounds are very ……………… and cannot be heard unless we listen attentively.
Answer:
soft

Question 3.
As long as the object ……………… the sound is heard.
Answer:
vibrates

Question 4.
When the vibration ……………… the sound also stops.
Answer:
stops

Question 5.
The intensity of sound is measured in a unit called ……………… .
Answer:
decibels(dB)

Question 6.
The voice box is located in our ……………… .
Answer:
throat

Question 7.
Sound travels in the form of ……………… through air, water and ……………. .
Answer:
waves, solids

Question 8.
The sound is propagated more clearly through a ……………… than through air.
Answer:
solid

Question 9.
Transmission of sound occurs at a different ……………… through different mediums.
Answer:
speed

Question 10.
Continuous noise which may have ill effects, is called noise ……………… .
Answer:
pollution

Question 11.
Some of the sounds that we enjoy can be a ……………… for others.
Answer:
nuisance

Question 12.
The vibration of an object is necessary for the ……………… of sound.
Answer:
production

Answer in one sentence.

Question 1.
List characteristics of sound.
Answer:
Sounds are soft, loud, pleasant and unpleasant.

Question 2.
What do you mean by unpleasant sounds?
Answer:
The sounds by which we get annoyed are called unpleasant sounds.

Question 3.
What do you mean by loud and soft sounds?
Answer:
The sounds which are heard easily, are loud sounds and the sounds which cannot be heard unless we listen attentively, are soft sounds.

Question 4.
Which movement is exhibited by diaphragm of a speaker and a tabla?
Answer:
Diaphragm of a speaker and a tabla exhibit rapid oscillatory motion which gives rise to vibrations.

Question 6.
What is source of the sound?
Answer:
The object due to which sound is produced is called the source of the sound.

Question 7.
What is acoustics?
Answer:
The science of sound, resonance, production, propagation and effects of sound is called acoustics.

Question 8.
What produces sound in living beings?
Answer:
The vibration of the vocal chords in our larynx or voice box produces sound.

Question 9.
On what does quality of sound depend?
Answer:
Quality of sound produced in the larynx depends upon the tautness of the vocal chords.

Question 10.
How is sound propagated?
Answer:
The sound is propagated in the form of waves through air, water or through a solid.

Question 11.
Why is sound heard more clearly through solids?
Answer:
Transmission of sound occurs at a different speed through different mediums. Transmission of sound is faster through a solid than through a liquid and gas.

Question 12.
What is noise?
Answer:
A loud sound is harsh to ears. Such sounds produce noise.

Question 13.
List the effects of very loud or continuous noise on the people.
Answer:

Very loud or continuous noise can cause hearing impairment.
This can even lead to deafness.
It also causes restlessness, irritability and mental exhaustion.

Question 14.
What is noise pollution?
Answer:
Continuous noise which has ill effects is called noise pollution.

Question 15.
How can we prevent noise pollution with respect to watching TV?
Answer:
The volume of the TV or radio in the house should be restricted to those watching the programmes.

Explain the terms.

Question 1.
Propagation of sound:
Answer:
Sound is said to be propagated when sound waves spread in all directions from a source of sound.

Question 2.
Medium of propagation of sound:
Answer:
The substance around a source of sound through which sound waves spread is called the medium of propagation of sound.

Question 3.
Which sounds do you hear during the recess in the school?
Answer:
During the recess in the school, we hear.

laughing
students running
talking loudly
ringing of the bell
stamping on the staircase
shouting

Question 4.
When there is silence in the classroom, close your eyes and sit quietly. Which sounds in your surroundings can you hear now?
Answer:

Loud: Laughing, running, talking, horn of cars, marriage procession, school band, teacher’s voice in next classroom.
Pleasant: P.T. teacher’s whistle, chirping of birds.
Unpleasant: Shouting, bell ringing, stamping on staircase, dog barking, horns of vehicles.

Question 5.
When a song is being played on a radio or a music system in the house, place your hand on its speaker. What do you feel? Put off the music. What do you feel now?
Answer:

When a hand is placed on the speakers of the music system, we feel vibrations on the hand.
When music is put off, we don’t feel any vibrations on the hand.

Question 6.
When a metal dish falls on the floor; it makes a loud noise. What do we do to stop the noise? What is the effect of that action?
Answer:
To stop the noise of metal dish falling on the floor, quickly put hand on the dish. Vibrations of the metal dish are stopped and the noise stops.

Question 7.
What is it that vibrates when the sounds of sitar, bell, water tap, and breaking of a saucer, etc. are produced?
Answer:
Strings of the sitar, tongs of the bell, water drops hitting the floor of the basin, pieces of saucers that hit the ground vibrate to produce the sounds.

Question 8.
Take a pot full of water. Strike it lightly on the rim. What do you see? Why are waves formed on the water in the pot?
Answer:

We see ripples on the water.
When we strike the rim of the pot, our striking causes vibrations. These vibrations are transferred or moved from the pot to the water. Hence, water waves/ripples are seen on the water in the pot.

Question 9.
On rubbing balloon filled with water and another filled with air, of which balloon do we hear a clear or sound?
Answer:
We hear a clearer sound of the water balloon.

Question 10.
If a bell is rung in a vacuum container, will its sound be heard outside?
Answer:
Its sound will not be heard outside.

Observe and Discuss.

Observe the figure and answer the questions.

Question 1.
Which of these sounds is pleasant?
Answer:
The singing of the girl is a pleasant sound.

Question 2.
Which sound is a nuisance to people?
Answer:

Boy shouting/screaming.
Boy moving/ walking with a toy rattle.

Observe the figure and answer the following.

Question 1.
Make a list of all sounds implied in the picture.

Answer:

Chirping of bird outside the house on the tree.
Collision of two vehicles – honking of the vehicles.
Baby crying.
Father talking on the phone.
Brother playing in the house – jumping.
Sister playing the drum – hitting the drum.
Sound of TV.
Dog barking.
Mother talking to the neighbour.

Question 2.
How would this atmosphere affect a person who is not feeling well?
Answer:
This atmosphere is not convenient for a patient who is ill. He cannot take rest.

Question 3.
Would you be able to study in these conditions?
Answer:
No, students cannot study in this condition. They cannot concentrate on their study.

6th Std Science Questions And Answers:

Plants: Structure and Function Class 7 Science Chapter 2 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 2 Plants: Structure and Function Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 2 Plants: Structure and Function Question Answer Maharashtra Board

Class 7 Science Chapter 2 Plants: Structure and Function Question Answer Maharashtra Board

1. Give examples of 3 plants that have:

Question a.
Spiny fruits
Answer:
Jack fruit, Pineapple, Lychee (litchi), Datura

Question b.
Spiny stem
Answer:
Cactus, Wild rose, Catclaw acacia, Silk, Cotton

Question c.
Red flowers
Answer:
Rose, Dahlia, Hibiscus, Tulips,

Question d.
Yellow flowers
Answer:
Marigold, Daffodil, Sunflower, Daisy

Question e.
Leaves which close at night
Answer:
Mimosa plant, Tallwood, Prayer plant, Gulmohar

Question f.
Single seeded fruits
Answer:
Mango, Lychee, Jamun

Question g.
Many seeded fruits
Answer:
Custard apple, Papaya, Watermelon.

2. Observe any one flower and its various parts and describe it in your own words.

Question a.
Answer:

A flower has following parts:
1. Pedicel: (a) Flower may have a long or a short stalk called pedicel, (b) One end of the pedicel is attached to the stem, (c) The other end of the pedicel is expanded and swollen. It is called the receptacle, (d) Petals and other parts of the flower are supported on the receptacle.
2. Calyx: In the bud condition, the petals are covered by leaf like parts called sepals which are green in colour. They form the calyx.
3. Corolla: This is made up of colourful parts called petals.
4. Androecium: (a) This is the male reproductive part of the flower, (b) It consists of stamens, (c) Each stamen is made up of anther and filament.
5. Gynoecium: (a) This is the female reproductive part of the flower, (b) This is made up of carpels, (c) A carpel consists of stigma, style and ovary.

3. What are the similarities and differences between?

Question a.
Jowar and Moong
Differences:

Jowar	Moong
i. It has fibrous root.	i. It has tap root.
ii. It is a monocotyledonous seed.	ii. It is a dicotyledonous seed.
iii. It is a rabi crop.	iii. It is a kharif crop

Similarities:
Jowar and Moong both are angiosperms.

Question b.
Onion and Coriander
Differences:

Onion	Coriander
i. It is a biennial plant.	i. It is an annual plant.
ii. It has monocotyledonous seed.	ii. It has dicotyledonous seeds.
iii. It has fibrous root.	iii. It has tap root but later on changes to fibrous root system.

Similarities:

Both are used in cooking.
Both are edible.
Both belongs to kingdom plantae.

Question c.
Leaves of banana and Leaves of mango
Answer:

Leaves of banana	Leaves of mango
i. It has parallel venation.	i. It has reticulate venation.
ii. It is very large in size.	ii. It is small in size.
iii. It is a monocotyledonous plant.	iii. It is a dicotyledonous plant.

Question d.
Coconut tree and Jowar stalk plant
Answer:
Differences:

Coconut tree	Jowar stalk plant
i. It is tall and has a thick stem	i. It is small and has a thin stem.
ii. It has strong root system.	ii. It has weak root system.
iii. Each and every part of tree is useful.	iii. Only seeds are useful.

Similarities:

Both are from same kingdom plantae.
Both are autotrophic.
Both are monocotyledonous plants.

4. Explain the following images in your own words.

Question a.

Answer:

Diagram A is of maize seed. It is a monocotyledonous seed and does not divide into two equal parts. The plant has fibrous root system.
Diagram B is of bean seed. It is a dicotyledonous seed and it divides into two equal parts. The plant has tap root system.

5. Describe the functions of various parts of a plant.

Question a.
Describe the functions of various parts of a plant.
Answer:
The functions of various parts of a plant are as below.
1. Root: (a) Fixation: It anchors the plant body to the soil, so helps in fixation, (b) Absorption: It absorbs water and nutrients from the soil, so helps in absorption, (c) Conduction: The root translocates water and mineral salts into the stem. (d) Storage: A certain amount of food is stored in the root which is utilized as it grows.
(e) Preventing soil erosion: It helps to bind the soil particles and prevent them from being blown away by wind or water.
2. Stem: (a) It supports and holds leaves, flower and fruits, (b) The stem conducts the water and minerals from roots to leaves and fruits, (c) It stores the food.
3. Leaves: (a) It synthesizes food for the plant, (b) Stomata, the tiny openings in the leaf help in gaseous exchange and are responsible for the process of transpiration.
4. Flower: It helps in pollination.
5. Fruit: (a) It protects the seed, (b) It helps in seed dispersal.
6. Seed: A new plant develops from it.

6. Certain properties are mentioned below. Find a leaf corresponding to each property and describe those plants.

Question a.
Certain properties are mentioned below. Find a leaf corresponding to each property and describe those plants.
leaves with smooth surface, leaves with rough surface, fleshy leaf, spines on leaf.
Answer:

Leaves with smooth surface: e.g. Banana leaf. It is large in size. It is closely rolled up one over the other. Together they look like a trunk but they form only an apparent trunk. It has parallel venation.
Leaves with rough surface: e.g. Hibiscus leaf. It has reticulate venation. Leaf margin is toothed.
Fleshy leaf: e.g. Jade plant, water hyacinth. It has fleshy, glossy and smooth leaves. They are coloured jade green and having a slightly red tinge towards the edge of leaves when exposed to higher level of light.
Spines on leaf: e.g. Opuntia, Ci/cas, kevda. Opuntia is a desert plant. Leaf is thick, fleshy and having spines on it.

7. Find the plant parts.

Question a.

Answer:

ROOT, ROOT CAP, ROOT HAIR, BUD, PETALS, STEM, RADICLE, FLOWER, LEAF, VEIN, CALYX, NODE, OVUM.

Class 7 Science Chapter 2 Plants Structure And Function Question Answer Activity:

Sketch various types of leaves in Paintbrush on the computer and save the sketches in a folder of your own name.

Class 7 Science Chapter 2 Plants: Structure and Function Important Questions and Answers

Plants Structure And Function Exercise Fill in the blanks:

Plants Structure And Function Class 7 Questions And Answers Question 1.
The part that grows from inside the seed towards the soil is called the …………….. .
Answer:
radicle

Plants Structure And Function Class 7 Question 2.
The part that grows above the soil from the seed is called the …………….. .
Answer:
plumule

Plants Structure And Function Question And Answer Question 3.
The part of the plant growing below the soil from radicle for support is called …………….. .
Answer:
root

Plants Structure And Function Class 7 Exercise Question 4.
The …………….. protects the root-tip from injuries.
Answer:
root cap

Plants Structure And Function Exercise Question 5.
Roots bearing hair like processes near the root tips are called …………….. .
Answer:
root hairs

Class 7 Science Chapter 2 Plants Structure And Function Question Answer Question 6.
Thread-like or fibre like roots arising from the stem are called ……………. .
fibrous roots

Question 7.
The stem grows above the soil from the …………….. of the sprouting seed.
Answer:
plumule

Question 8.
Leaves come out at the …………….. .
Answer:
nodes

Question 9.
The part of the stem between two nodes is called …………….. .
Answer:
inter node

Question 10.
The tip or the apical end of the stem is called a …………….. .
Answer:
bud

Question 11.
The broad, spread out part of the leaf is called the …………….. or …………….. .
Answer:
leaf blade, lamina

Question 12.
The tip of the leaf is called the …………….. .
Answer:
leaf apex

Question 13.
Leaves of some plants have a stalk called a …………….. .
Answer:
petiole

Question 14.
The portion of the leaf attached to the stem is called the …………….. .
Answer:
leaf base

Question 15.
Small leaf like structures near the leaf base is called …………….. .
Answer:
stipides

Question 16.
Flowers may have a long or a short stalk called …………….. .
Answer:
pedicel

Question 17.
One end of the pedicel is attached to the …………….. .
Answer:
stem

Question 18.
…………….. is a male reproductive organ of the flower.
Answer:
Androecium

Question 19.
…………….. is a female reproductive organ of the
Answer:
gynoecium

Question 20.
Androecium consists of …………….. .
Answer:
stamens

Question 21.
Gynoecium consists of …………….. .
Answer:
carpels

Question 22.
Seeds which get divided into two equal parts are called …………….. seeds.
Answer:
dicotyledonous

Question 23.
Seeds which do not divide into two equal parts are …………….. called seeds.
Answer:
monocotyledonous

Question 24.
Petals and other parts of the flower are supported on the …………….. .
Answer:
receptacle

Question 25.
Sepals are …………….. in colour.
Answer:
green.

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
1. Peepal	a. carpels
2. Maize	b. stamen
3. Androecium	c. parallel venation
4. Gynoecium	d. reticulate venation

Answer:

Column ‘A’	Column ‘B’
1. Peepal	d. reticulate venation
2. Maize	c. parallel venation
3. Androecium	b. stamen
4. Gynoecium	a. carpels

Question 2.

Column ‘A’	Column B’
1. Tap roots	a. stem
2. Fibrous roots	b. root
3. Radicle	c. monocotyledonous plants
4. Plumule	d. dicotyledonous plants

Answer:

Column ‘A’	Column B’
1. Tap roots	d. dicotyledonous plants
2. Fibrous roots	c. monocotyledonous plants
3. Radicle	b. root
4. Plumule	a. stem

Question 3.

Column A’	Column B’
1. Leaf-tip	a. petiole
2. Edge of leaf blade	b. leaf margin
3. Portion of leaf attached to stem	c. lamina
4. Stalk of leaf	d. leaf apex
	e. leaf base

Answer:

Column A’	Column B’
1. Leaf-tip	d. leaf apex
2. Edge of leaf blade	b. leaf margin
3. Portion of leaf attached to stem	e. leaf base
4. Stalk of leaf	a. petiole

Say whether True or False Correct and rewrite the false statements:

Question 1.
Stem grows from radicle.
Answer:
False. Stem grows from the Plumule

Question 2.
Leaf margins may be entire, dentate or lobed.
Answer:
True

Question 3.
The leaf blade of leaves in some plants is divided into many small parts called leaflets.
Answer:
True

Question 4.
Maize plant has reticulate venation.
Answer:
False. Maize plant has parallel venation

Question 5.
A carpel consists of stigma, style and ovary.
Answer:
True.

Question 6.
A stamen is made up of nodes and internodes.
Answer:
False. A stamen is made up of anther filament

Question 7.
The ovary develops into a fruit.
Answer:
True

Question 8.
Fertilized ovules form the seeds.
Answer:
True

Question 9.
A mango fruit contains many seeds.
Answer:
False. A mango fruit contains only one seed

Question 10.
A fruit like cashew have seed outside the fruit.
Answer:
True.

Question 11.
Leaves of some plants do not have a petiole.
Answer:
True

Question 12.
The peepal leaf has parallel venation.
Answer:
False. It has reticulate venation.

Find the odd one out:

Question 1.
Pea, Moong, maize, groundnut
Answer:
Maize – Its seed is monocotyledonous, while others have dicotyledonous seeds.

Question 2.
Cashew, apple, mango, chikoo
Answer:
Cashew – Its seed is outside the fruit, others have internal seeds.

Question 3.
Stigma, anther, style, ovary
Answer:
Anther – It is a part of androecium, while others are a part of gynoecium.

Question 4.
Petiole, vein, calyx, apex
Answer:
Calyx – It is a part of flower, whereas others are parts of leaf.

Question 5.
Aerial, stilt, runner, lobed
Answer:
Lobed – It is a type of leaf margin, while others are types of modified roots.

Answer the following in one or two sentences:

Question 1.
Which types of roots do the fenugreek, spinach and onion plants have?
Answer:

Fenugreek and spinach have tap roots with a few secondary roots whereas onion has fibrous root.
Fenugreek roots also have some nodules which contain nitrogen fixing bacteria.

Question 2.
What are called prop roots?
Answer:
Roots emerging from the trunk and branches of a banyan tree grow towards the soil. These roots are called prop roots.

Question 3.
What is called reticulate venation?
Answer:

A leaf is divided into two equal parts by a single mid-vein which lies along the midline of the leaf blade.
Secondary veins arise from the mid-vein. They are branched and form a network or reticulum. Such a type of venation is called reticulate venation.

Question 4.
What is called parallel venation?
Answer:
In a leaf all the veins are parallel, running from the leaf base to the leaf apex. Such a venation is called parallel venation.

Question 5.
What is pollination?
Answer:
After maturity, anthers burst and the pollen grains which are released fall on the stigma. This process is called pollination.

Question 6.
Why are the underground parts of plants like radish, carrot, beet and sweet potato thick, fleshy and swollen? Which parts of the plant are they?
Answer:
The underground parts of plants like radish, carrot, beet and sweet potato are thick, fleshy and swollen because they store food in the form of starch. These are the root part of the plant.

Distinguish between:

Question 1.
Tap roots and fibrous roots.
Answer:

Tap roots	Fibrous roots
1. Roots of some plants produce secondary roots that grow obliquely and spread far and wide in the soil. This type of root is called a tap root.	1. Thread like or fibre roots arising from the stem are called fibrous roots.
2. It is found in dicotyledonous plant.	2. It is found in monocotyle-donous plant.

Question 2.
Dicotyledonous seeds and monocotyledonous seeds.
Answer:

Dicotyledonous seeds	Monocotyledonous seeds
1. Seeds which get divided into two equal parts are called dicotyledonous seeds.	1. Seeds which do not divide into two equal parts are called monocotyledonous seeds.
2. Dicotyledonous seeded plants have tap root system.	2. Monocotyledonous seeded plants have fibrous root system.

Draw neat and labelled diagram for the following:

Question 1.
Tap root
Answer:

Question 2.
Parts of a leaf.
Answer:

Question 3.
Parts of stem
Answer:

Do as directed:

Question 1.
Certain properties are mentioned below. Find a leaf corresponding to each property and describe those plants.
Answer:

Leaves with smooth surface: e.g. Banana leaf. It is large in size. It is closely rolled up one over the other. Together they look like a trunk but they form only an apparent trunk. It has parallel venation.
Leaves with rough surface: e.g. Hibiscus leaf. It has reticulate venation. Leaf margin is toothed.
Fleshy leaf: e.g. Jade plant, water hyacinth. It has fleshy, glossy and smooth leaves. They are coloured jade green and having a slightly red tinge towards the edge of leaves when exposed to higher level of light.
Spines on leaf: e.g. Opuntia, Cycas, kevda. Opuntia is a desert plant. Leaf is thick, fleshy and having spines on it.

Use your brainpower!

Answer the following questions:

Question 1.
What would have happened if plants like tamarind, banyan and mango had fibrous roots?
Answer:
If plants like banyan, mango, tamarind had fibrous roots they would get uprooted and fall even with a little strong wind as the roots would not be able to support and anchor the trees firmly.

Question 2.
What will happen if the root-tip is injured?
Answer:

Root cap helps the root to grow downward It protects the sensitive part of the root and eases the movement of the root through the soil.
Injury of the root tip causes the root to grow randomly and it also may lead to injury of the sensitive part of the root.

Question 3.
Which types of roots do the fenugreek, spinach and onion plants have?
Answer:

Fenugreek and spinach have tap roots with a few secondary roots whereas onion has fibrous root.
Fenugreek roots also have some nodules which contain nitrogen-fixing bacteria.

Question 4.
Of what use to a plant are the insects flitting about around its flowers?
Answer:

The insects try to suck the nectar from the flowers and in that process the pollen grains stick to their legs.
When they sit on another flower the pollen grain stick to the stigma and the pollination takes place. Thus, these insects help in the pollination.

Observe the figure and answer the questions given.

Question a.
What is shown in the picture?
Answer:
The picture shows the arrangement of leaves on the stem.

Question b.
What arrangement is shown in (A), (B), and (C)?
Answer:
(A) Alternate (B) Opposite (C) Whorled

Question a.
Lable parts 1 to 6.
Answer:

Gynoecium or carpel
Corolla
Androecium (Stamen)
Ovary
Corolla
Pedicel

Question b.
Name the female reproductive part.
Answer:
Gynoecium

Question c.
Name the colourful part of the flower.
Answer:
Corolla

Question d.
Which part develops into fruit?
Answer:
Ovary

Question e.
Which pa pollination?
Answer:
The transfer of pollen grains from the anther to the stigma of flower is called pollination.

7th Std Science Questions And Answers:

Nutrition and Diet Class 6 Science Chapter 7 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 6 Science Solutions Chapter 7 Nutrition and Diet Notes, Textbook Exercise Important Questions and Answers.

Std 6 Science Chapter 7 Nutrition and Diet Question Answer Maharashtra Board

Class 6 Science Chapter 7 Nutrition and Diet Question Answer Maharashtra Board

1. Fill in the blanks:

Question a.
The process of intake of food and utilizing it for all life processes is called ……………. .
Answer:
nutrition

Question b.
All the substances in our food which are useful for various body processes are called ………… .
Answer:
nutrients

Question c.
Carbohydrates and …………. provide …………… to our body.
Answer:
fats, energy

Question d.
In a balanced diet, all the nutrients are present in the ……………. proportion.
Answer:
right

Question e.
In the food pyramid, cereals are given the maximum space because they fulfill our …………… requirement.
Answer:
energy

Question f.
Intake of more food than necessary causes ………….. .
Answer:
overnutrition

2. Spot the following in the table of vitamins and minerals.

Question a.
The nutrient present in citrous fruits.
Answer:
Vitamin C

Question b.
Vitamins/minerals present in milk.
Answer:
Vitamin A, Vitamin B, Vitamin D, calcium, phosphorus.

Question c.
Causes and symptoms of night blindness, scurvy, rickets, beriberi.
Answer:

Diseases	Causes	Symptoms
1. Night blindness	Deficiency of Vitamin A	Inability to see in dim light
2. Scurvy	Deficiency of Vitamin C	Bleeding of gums
3. Rickets	Deficiency of Vitamin D	Softening of bones
4. Beri-beri	Deficiency of Vitamin B₁	Nerve disorder, muscle weakness

Question d.
Foods required to prevent the above diseases.
Answer:

Diseases	*Causes	‘Symptoms	Food for prevention
1. Night blindness	Deficiency of Vitamin A	Inability to see in dim light	Carrots, milk, dark green vegetables.
2. Scurvy	Deficiency of Vitamin C	Bleeding of gums	Amla, kiwi, oranges and citrus fruits.
3. Rickets	Deficiency of Vitamin D	Softening of bones	Exposure to sunlight, milk, fish, egg, butter.
4. Beri-beri	Deficiency of Vitamin B₁	Nerve disorder, muscle weakness	Milk, fish, meat, cereals, nuts, pulses

Question e.
Causes of anaemia.
Answer:
Deficiency of Vitamin B₁₂, iron.

Question f.
Essential mineral for healthy bones and teeth.
Answer:
Calcium, phosphorus.

Question g.
Sensory organ affected due to the deficiency of Vitamin A.
Answer:
Eyes, skin.

3. Choose the correct alternative.

Question a.
Pulses are a very good source of ……………. .
(1) carbohydrates
(2) proteins
(3) fats
(4) minerals
Answer:
(2) proteins

Question b.
…………. provide maximum energy to our body.
(1) Cereals
(2) Leafy Vegetables
(3) Water
(4) Amla
Answer:
(1) Cereals

Question c.
Goitre is caused by the deficiency of ……….. .
(1) iron
(2) calcium
(3) iodine
(4) potassium
Answer:
(3) iodine

Question d.
……….. is a type of junk food.
(1) Orange
(2) Milk
(3) Bhakri
(4) Chocolate
Answer:
(4) Chocolate

4. Use the food pyramid to select food items of your choice for three days.
Conditions:
1. The diet for all three days should be balanced.
2. There should be variety in the items chosen for the three days.
Answer:

Day 1:
Cereal like cornflakes and milk, apple, roti, sabzi and dal.

Day 2:
Bread and butter with milk, rice/ roti and chicken, curd, any one type of fruit, salad.

Day 3:
Poha, green vegetable and dal with rice or roti, raita, one fruit, vegetable sandwich.

Activity:

Question 1.
Obtain information on simple methods of spotting the adulteration in foodstuffs and try them out.

Class 6 Science Chapter 7 Nutrition and Diet Important Questions and Answers

Choose the correct alternative:

Question 1.
Vitamin ……………. and vitamin …………….. dissolve easily in water.
(a) A, B
(b) B, C
(c) B, D
(d) B, E
Answer:
(b) B, C

Question 2.
……………. carries oxygen to all parts of the body.
(a) Calcium
(b) Iron
(c) Iodine
(d) Sodium?
Answer:
(b) Iron

Question 3.
Deficiency of vitamin ……………. causes excessive bleeding after an injury.
(a) A
(b) B
(c) K
(d) D
Answer:
(c) K

Question 4.
In accordance with the food pyramid, the proportion of ……………. should be least in our diet.
(a) cereals
(b) fruits
(c) milk
(d) oil
Answer:
(d) oil

Question 5.
……………. is a rich source of vitamin C.
(a) Carrot
(b) Amla
(c) Meat
(d) Milk
Answer:
(b) Amla

Question 6.
Children of growing age need to get approximately ……………. to ……………. calories from the food they eat.
(a) 1500-2000
(b) 3150-4150
(c) 2000-2500
(d) All of them
Answer:
(c) 2000-2500

Fill in the blanks:

Question 1.
All food that we consume during the day is together called our ………. .
Answer:
diet

Question 2.
………….. convert milk into yogurt.
Answer:
Probiotics.

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
1. Carbohydrates	a. resistance to diseases
2. Proteins	b. energy
3. Fibre	c. growth
4. Vitamins	d. excretion

Answer:

Column ‘A’	Column ‘B’
1. Carbohydrates	b. energy
2. Proteins	c. growth
3. Fibre	d. excretion
4. Vitamins	a. resistance to diseases

Question 2.

Column ‘A’	Column ‘B’
1. Iron	a. Goitre
2. Calcium and phosphorous	b. Anaemia
3. Iodine	c. Inefficiency of muscles
4. Sodium and potassium	d. Weak bones

Answer:

Column ‘A’	Column ‘B’
1. Iron	b. Anaemia
2. Calcium and phosphorous	d. Weak bones
3. Iodine	a. Goitre
4. Sodium and potassium	c. Inefficiency of muscles

Question 3.

Column ‘A’	Column ‘B’
1. Vitamin A	a. Scurvy
2. Vitamin C	b. Excessive bleeding
3. Vitamin D	c. Skin disorders
4. Vitamin E	d. Nightblindness
5. Vitamin K	e. Rickets

Answer:

Column ‘A’	Column ‘B’
1. Vitamin A	d. Nightblindness
2. Vitamin C	a. Scurvy
3. Vitamin D	e. Rickets
4. Vitamin E	c. Skin disorders
5. Vitamin K	b. Excessive bleeding

Pick out the odd one:

Question 1.
Chocolate, chapatti, banana, milk
Answer:
Chocolate

Question 2.
Rice, chapatti, carrot, dal.
Answer:
Carrot

Question 3.
Scurvy, Rickets, Beriberi, Goitre.
Answer:
Goitre

Question 4.
Vitamin A, Vitamin C, Vitamin D, Vitamin E
Answer:
Vitamin C

Answer the following:

Question 1.
Why do living things need food and water?
Answer:
Living things take food and water and use them for:

Obtaining energy
Growth of the body
Carrying out day to day functions of the body.
Fighting against diseases

Question 2.
Name the main nutrients in our food.
Answer:
There are six main nutrients in our food. They are:

Carbohydrates
Fats
Proteins
Fibres
Vitamins
minerals

Question 3.
How do we get energy from the food?
Answer:

We get energy in the form of heat from the food we eat.
Heat is measured in kilocalories (calories).
Hence, the energy in food items is also measured in kilocalories (calories).

Question 4.
Vitamin C rich food should be eaten raw. Why?
Answer:

Vitamin C is very sensitive to heat and light.
It is destroyed easily during cooking. Hence, Vitamin C rich food should be eaten raw.

Question 5.
What is balanced diet? Give its significance.
Answer:
A diet containing adequate quantities of all nutrients is called as balanced diet. Significance of a balanced diet are:

An increased capacity to work.
Good physical and mental health.
Increased capacity to fight/resist diseases.
Helps in proper growth of the body.

Question 6.
What is obesity? How to avoid obesity?
Answer:

Obesity is the state of being overweight.
Junk food eaten frequently causes obesity.
Obesity is not good for health.

To avoid obesity:

Have a balanced diet.
Eat whole grains, fruits and vegetables with their skins.
Increase use of bicycles.
Play more outdoor games.
Do not eat if you are not hungry.
Do not watch T.V while eating.
Avoid precooked, packaged food.
Exercise regularly.

Write short notes.

Question 1.
Vitamins:
Answer:
1. Vitamins are vital substances required by our body in small quantities. They help to improve the body’s resistance to diseases. Their deficiency can lead to various diseases, e.g.: deficiency of Vitamin A causes night blindness and that of Vitamin D causes rickets. The sources of vitamins are vegetables, fruits, milk, fish, meat etc.
2. There are two kinds of vitamins – water soluble vitamins and water insoluble vitamins.
3. Vitamin B and Vitamin C are water soluble vitamins because they dissolve easily in water. They are thrown out of the body through the water in sweat and urine. Hence, a regular supply of these vitamins is essential. B₁₇B₂, B₃, B₆, B₉, and Bp are the types of vitamin B.
4. Vitamins A, D, E and K are insoluble in water but are fat soluble vitamins. They get stored in the body.

Question 2.
Probiotics:
Answer:

The useful microorganisms which convert milk into yoghurt are present in yoghurt and buttermilk are called probiotics.
Lakhs of such useful microorganisms are present in our intestine.
They are essential for our health.
Hence, to maintain them in our body we should include food rich in probiotics in our daily diet.

Question 3.
Junk food:
Answer:

Foods which gives us energy but do not supply the necessary nutrients are called junk food.
Foods like chocolate, pizzas, burgers, noodles, fried foods like pakodas are junk food.
These foods contain refined flour, sugar and oil in large proportion.
If we consume these foods frequently, our body experiences shortage of proteins, vitamins and minerals.
This may lead to malnutrition and obesity.

Question 4.
Adulteration of food:
Answer:
To earn more profits, cheaper substances of low quality called adulterants, are mixed with the foodstuffs. The mixing adulterants to foodstuffs is called adulteration of food. Adulterants may be poisonous or harmful and such food is impure and unfit for consumption.
Some of the adulterants added to foodstuffs are given below:

Give scientific reasons:

Question 1.
Deficiency of vitamin B and C are common in our body.
Answer:

Vitamin B and vitamin C are water soluble vitamins.
They are thrown out of the body through the water in sweat and urine.
Hence, a regular supply of these vitamins is essential.
If we don’t intake food rich in these vitamins, deficiency occurs.

Question 2.
Exposure to sunlight is essential.
Answer:

On exposure to sunlight our body synthesizes Vitamin D from substances in milk, fish, eggs and butter.
Its deficiency causes softening of bones (Rickets).
Vitamin D helps in absorbing calcium and phosphorous for healthy bones and teeth.
Hence, exposure to sunlight is essential.

Complete the tables given below:

Nutrients	Source	Function
1. Carbohydrates	Rice, chapatti	Provide energy
2. Fats	Oil, butter	Provide energy
3. Proteins	Sprouts, meat, eggs	Growth, repairing wear and tear of the body.
4. Vitamins	Vegetables, fruits	Improve body’s resistance to diseases
5. Fibre	Sprouts, vegetable, fruits	Help in excretion

Mineral	Source	Function
1. Iron	Spinach, raisins	Carrying oxygen to all parts of the body
2. Calcium, phosphorous	Milk, milk products, meat	Strengthen bones and teeth
3. Iodine	Raisins, fish, sea fish	Controls growth, speeds up chemical reactions in the body.
4. Sodium and potassium	Salt, leafy vegetables, fruits, pulses	Maintain the body’s water balance and functioning of the muscles and nervous system.

Vitamins	Source	Function
1. A	Carrot, milk, vegetables	Protects eyes, helps to keep skin, bones and teeth healthy.
2. B₁	Milk, fish, cereals	Helps in proper function of nerves and heart.
3. B₉	Deep green vegetables, papaya, kiwi	Growth of the body
4. B₁₂	Meat, milk products	Formation of red blood cells
5. C	Amla, citrus fruits, green leafy vegetables	Protects body tissues
6. D	On exposure to sunlight, Vitamin D is made in our body	Formation of collagen – a protein essential for gums, teeth, bones and skin
7. E	Green leafy vegetables, vegetable oil	Metabolism, reproduction
8. F	Green leafy vegetables, sprouted pulses, yellow of egg	Helps in clotting of blood

Using the food items given below, prepare a balanced diet pyramid.
[Chapatti, banana, carrot, butter, Nan, egg, bread, cheese, dal, spinach, milk]
Answer:

Can you recall?

Question 1.
Which are the various groups of foodstuff? Which main constituents of food do we get?
Answer :
The various groups of foodstuffs are:

Milk and milk products, meat, fish, eggs.
Cereals and pulses
Vegetables and fruits.
Fatty substances oil, butter and ghee.

There are six main nutrients in our food: carbohydrates, fats, proteins, fibres, vitamins and minerals.

Nutrients	Foodstuffs
1. Carbohydrates	Cereals and pulses
2. Protein	Milk product, meat, fish, eggs
3. Fats	Butter, oil, ghee
4. Fibres	fruits and vegetables

Question 2.
What trouble do we have to face if we do not get enough fibre from our daily diet?
Answer:
Fibres help in excretion of food, if we do not get enough fibre we will face indigestion and stomach-ache.

Question 3.
What care must be taken to make sure that fibre is not lost or removed from the food we get?
Answer:
We must not over-cook the foodstuff containing fibres. Fruits should be eaten raw.

6th Std Science Questions And Answers:

Heat Class 7 Science Chapter 9 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 9 Heat Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 9 Heat Question Answer Maharashtra Board

Class 7 Science Chapter 9 Heat Question Answer Maharashtra Board

Fill in the blanks:

Question a.
Maximum heat is absorbed by a ………….. coloured object.
Answer:
black

Question b.
……………. of heat does not require a medium.
Answer:
Radiation

Question c.
Conduction of heat takes place through a ……………. substance.
Answer:
solid

Question d.
The shining surface in a thermos flask decreases the outgoing heat by ……………… .
Answer:
reflection

Question e.
Cooking utensils are made from metals due to their property of ……………… .
Answer:
conduction

Question f.
The earth receives heat from the sun by ………………. .
Answer:
radiation

2. What will absorb heat?
Steel spoon, wooden board, glass vessel, iron griddle (lava), glass, wooden spoon, plastic plate, soil, water, wax.

Question a.
What will absorb heat?
Steel spoon, wooden board, glass vessel, iron griddle (lava), glass, wooden spoon, plastic plate, soil, water, wax.
Answer:
Following will absorb heat fast: steel spoon, iron griddle, water, wax. Remaining objects also obsorb heat but very slowly.

3. Write Answers to the following questions.

Question a.
How does a fever get lowered by putting a cold compress on the forehead of a patient?
Answer:
The water in the cold compress will evaporate by the heat of fever thus taking some local heat of the body and temperature of the body is lowered, therefore the fever gets lowered by putting a cold compress on the forehead of a patient.

Question b.
Why are the houses in Rajasthan painted white?
Answer:
Rajasthan being a desert, temperature is very high. So there is excess heat. White colour doesn’t absorb the heat but reflects back, so houses will not become hot due to excess heat and inside of the house will be cool. So the houses in Rajasthan are painted white.

Question c.
What are the modes of heat transfer?
Answer:
There are three modes of heat transfer:

conduction
convection
radiation.

Question d.
Explain which mode of heat transfer causes sea breezes and land breezes?
Answer:

Unequal heating of air above the sea and land sets up convection currents which cause sea breezes during the day time.
The land near the sea is heated by sunlight to a higher temperature than the sea.
As the air above the land is heated, it becomes lighter and moves upwards, its place is then taken by cooler air moving from the sea towards the land.
Sea breezes are thus set up. At night, the land cools faster than water in the sea. Therefore air above sea water is hotter than air above the land.
So cooler air from the land moves towards the sea forming land breeze.

Question e.
Why is the outer coat of the penguins of Antarctica black?
Answer:
The outer coat of the penguins of Antarctica is black because black colour absorbs heat so penguins get lots of heat due to this black colour and they can live easily in very, very cold Antarctica region.

Question f.
Why are heaters fitted near the floor and air conditioners near the ceiling of a room?
Answer:
1. Due to air conditioners, air becomes cool so its density increases and it becomes heavy. So it goes down and warm air with less density comes up and take the place of cold air. This cycle goes on and on and the whole room becomes cool.
2. If it is fitted near the floor then cool air of high density can’t go up and upper air with low density cannot come down and cooling of the room does not take place properly so air conditioners are fitted near the ceiling of a room.
3. Heaters are fitted near the floor. Due to heating, air becomes hot which is lighter than cold air. So it goes up and upper air with high density comes down.
4. This cycle goes on and on and the full room becomes warm. So heaters are fitted near the floor.

4. Give scientific reasons.

Question a.
An ordinary glass bottle cracks when boiling water is poured into it, but a borosil glass bottle does not.
Answer:

An ordinary glass bottle cracks when we pour boiling water into it because there is a lot of temperature difference between the inner and outer parts of the glass.
The inner part gets hot and expands while the outer part remains cold since glass is a bad conductor of heat.
This unequal expansion causes the crack of glass bottle.
But the borosil glass bottle has a very high melting point so the temperature difference is very less, hence it doesn’t crack.

Question b.
The telephone wires which sag in summer become straight in winter.
Answer:

Telephone wires are made up of copper metal. Metals expand on heating.
In summer the copper wire expands, thus the length of the wire increases between the two poles and instead of remaining straight it sags.
In winter due to cold, it contracts and comes back to the original position, so it becomes straight in winter.

Question c.
Dewdrops form on the grass in winter.
Answer:

During the winter, the temperature of air is low, its capacity to hold the vapour is less.
At such times the excess water vapour is transformed into water droplets due to cold. And so the dew drops form on the grass in winter.

Question d.
In winter, why does an iron pillar feel colder than a wooden pole.
Answer:

Iron is a metal and metals are very good conductors of heat so it transfers heat at a much faster rate than wood.
That means, when we touch them, metals conducts away energy in the form of heat emitted by our hand and temperature of our hand lowers down and we get a cold’ sensation.
This is what makes the metal appear colder than the wood.
The wood is taking away heat at a much slower rate.

Project:

Question 1.
Make a note of the various examples of heat transfer seen in day-to-day life.

Class 7 Science Chapter 9 Heat Important Questions and Answers

Fill in the blanks:

Question 1.
………………… is an indicator of the heat in a substance.
Answer:
Temperature

Question 2.
………………. flows from higher temperature to lower temperature.
Answer:
Heat

Question 3.
Transfer of heat from one place to another takes place by ……………. or ……………. .
Answer:
conduction, convection, radiation

Question 4.
During conduction, particles of the substance …………….. in their place.
Answer:
vibrate

Question 5.
In a convection current, warm air travels …………….. .
Answer:
upwards

Question 6.
A …………….. is necessary for the conduction of heat.
Answer:
medium

Question 7.
The ………………. of conduction of heat through a medium depends on the medium.
Answer:
speed

Question 8.
Convection takes place only in …………… medium.
Answer:
fluid

Question 9.
Transfer of heat in the absence of a medium is called ……………… .
Answer:
radiation

Question 10.
Substances through which heat travels easily and quickly are called …………… .
Answer:
good conductors

Question 11.
Substances through which heat travels very slowly are called ………… of heat.
Answer:
bad conductors

Question 12.
Copper is a better ………… of heat than …………. .
Answer:
conductor, iron

Question 13.
………………. made first thermos flask in 1892.
Answer:
Sir James Dewar

Question 14.
Neither conduction nor convection of the heat occurs in thermos flask due to the ……………… .
Answer:
vacuum.

Match the following:

Question 1.

Column ‘A’	Column ‘B’
1. Good conductor	a. flow of particles
2. Bad conductor	b. particles vibrate
3. Conduction	c. glass
4. Convection	d. copper

Answer:

Column ‘A’	Column ‘B’
1. Good conductor	d. copper
2. Bad conductor	c. glass
3. Conduction	b. particles vibrate
4. Convection	a. flow of particles

Question 2.

Column ‘A’	Column ‘B’
1. Radiation	a. convection current
2. Black body	b. conduction
3. Vibration	c. absorbs more heat
4. A rotating paper lantern	d. no medium

Answer:

Column ‘A’	Column ‘B’
1. Radiation	d. no medium
2. Black body	c. absorbs more heat
3. Vibration	b. conduction
4. A rotating paper lantern	a. convection current

Say whether true or false, correct and rewrite the false statements:

Question 1.
Glass is a bad conductor of heat.
Answer:
True

Question 2.
In a thermos flask, hot things remain hot and cold things become warm.
Answer:
False. In a thermos flask, hot things remain hot and cold things remain cold.

Question 3.
Radiation of heat depends upon the colours of the outer surface of the body.
Answer:
True

Question 4.
During radiation, the particles of the medium vibrate.
Answer:
True

Question 5.
Copper is better conductor of heat than iron.
Answer:
True

Question 6.
During conduction, particles of the conductor leave their original place.
Answer:
False. During conduction, particles of the conductor do not leave their original place, but only vibrate in their own place.

Question 7.
Hot water is heavier than cold water.
Answer:
False – Hot water is lighter than cold water.

Question 8.
A convection current always travels down wards.
Answer:
False – A convection current always travels upwards.

Question 9.
Every warm substance continuously emits heat in all directions around itself.
Answer:
True

Question 10.
Air is a bad conductor of heat.
Answer:
True

Define the following:

Conduction
convection
radiation
Transfer of heat.

Answer:

Conduction: The transfer of heat from one end of a solid substance to the other, without the particles leaving their original place is called conduction.
Convection: Transfer of heat in fluids due to formation of currents is called convection.
Radiation: Transfer of heat in all directions in the absence of a medium is called radiation.
Transfer of heat: The flow of heat from one place to another is called transfer of heat.

Give scientific reasons:

Question 1.
Cricketers wear white clothes when playing in the sun.
Answer:
White clothes do not absorb heat but reflect back therefore cricketers wear white clothes while playing in the sun.

Question 2.
Sawdust is a bad conductor of heat.
Answer:
Sawdust is a bad conductor of heat because heat travels very slowly through it.

Question 3.
We can feel the heat of table lamp under it.
Answer:
We can feel the heat of table lamp under it because every warm substance continuously emits heat in all directions around itself by radiation.

Question 4.
Medium is necessary for conduction.
Answer:
Conduction is the transfer of heat from one end of a substance to another. Transfer of heat has to be done by particles of a substance and particles of a substance are particles of a medium. Hence, a medium is necessary for conduction.

Question 5.
Explain the structure and functioning of thermometer containers-
Answer:

Thermoware containers keep food hot. These containers consist two boxes fitted one inside the other.
The outer box is made up of plastic while the inner one is made up of a shiny metal, there is air between the two boxes.
Air is a bad conductor of heat. Thus, heat is not lost by either conduction or convection. Also, the shiny inner surface prevents heat loss due to radiation.
The container has a plastic lid. This also prevents any transfer of heat.

Question 6.
what is mailed infrared camera? Write its uses.
Answer:

Radiation of heat takes place from many objects in nature such as trees, mountains, stones and roads.
A camera has been developed which uses these radiations to make our surroundings visible even at night. This is called infrared camera.
It is used to keep watch on the movements of the enemy during the night.
It is also used to track the movements of animals in the wild.

Question 7.
Why is mercury used in a thermometer?
Answer:
Mercury is used in a thermometer because of the following properties.

There is a big difference between the freezing point and boiling point of mercury. Its freezing point is – 39° C and its boiling point is 357° C.
It is shiny and can be easily seen.
It does not stick to glass.
It expands regularly and uniformly in all conditions.

Question 8.
Write the difference between Conduction, Convection and Radiation.
Answer:

Conduction	Convection	Radiation
1. It is a mode of transfer of heat from hot part of an object to the cold part.	It is a mode of transfer of heat by means of convection currents.	It is a mode of transfer of heat in all directions without any medium.
2. It occurs in solids.	It occurs in liquids and gases.	It occurs in all objects of high temperature and vacuum.
3. It is a slow process.	It is a slow process	It is a fast process.

Question 9.
Draw and explain about the Thermos flask or Dewar flask.
Answer:

Principle:
1. As there is no medium in the vacuum between the two bottles, no transfer of heat can take place by conduction or convection.
2. Radiant heat is reflected back inside from the shiny surfaces.
3. Glass and plastic are bad conductors of heat hence they do not transfer heat either into or out of the bottle. Thus transfer of heat does not take place by any of the three modes, namely conduction, convection or radiation Hence, hot things in the flask remain hot and cold things cold.

Structure:

A thermos flask consists of two thin glass bottles fitted one inside the other.
The inner surfaces of the bottles have a silver coating to shine like a mirror.
A vacuum is created in the space between the two bottles by removing all the air from it.
A plastic or cork lid is provided to fit on the mouth of the bottle.

Draw neat labelled diagrams of:

Question 1.
The relation between density and convection
Answer:

Question 2.
Conduction of heat
Answer:

Question 3.
Convection of heat
Answer:

Question 4.
Expansion and contraction of a liquid
Answer:

Question 5.
Thermos flask
Answer:

Can you tell?

Answer the following questions:

Question 1.
Why does the halwai wrap up cloth around the end of his slotted spoon while stirring the boiling milk in his large kadhai?
Answer:
The halwai wrap up cloth around the end of his slotted spoon while stirring the boiling milk in his large kadhai because (i) His slotted spoon is made up of metal and metal is a good conductor of heat so due to constant heating spoon gets very hot which makes hand to get burnt, (ii) But cloth is a bad conductor of heat so it does not allow heat to reach till hand and halwai does not feel hot when he stirs the boiling milk.

Question 2.
Why do we hold a steel glass in a handkerchief while drinking hot milk from it?
Answer:

Steel is metal and it is a good conductor of heat. So due to hot milk it becomes hot and it is difficult to hold. Person’s hand get burnt due to it.
So it is better to hold in a handkerchief because handkerchief is made up of cloth which is a bad conductor of heat. So your hand does not feel hot.

Use your brain power!

Question 1.
Why do we wear woollen clothes in winter?
Answer:
We wear woollen clothes in winter because

Air is a poor conductor of heat and woollen clothes do not allow the transfer of body heat.
Therefore we do not feel cold in woollen clothes and get protected from cold in winter.

Question 2.
Why do we use white clothes in summer and dark or black clothes in winter?
Answer:

White clothes do not absorb heat, so in summer, weather is very hot and white clothes protect us from heat whereas in winter it is very cold so we need more heat.
Dark or black clothes absorb more heat so we get protection from cold.

Question 3.
Why is there a gap at the joints of rails and of cement concrete bridges?
Answer:

The joints of rails and cement concrete bridges are made of iron. Metal is a good conductor of heat so in summer due to heat it expands and its length will be increased.
To allow for this expansion, gaps are kept.
If these gaps are not kept, then after expansion the rails and cement concrete would have buckled upwards due to lack of space.
Due to that bridges would crack and railway tracks get crooked.

Question 4.
Why is mercury or alcohol used in a thermometer?
Answer:
Mercury is used in a thermometer because of the following properties.
Alcohol is used in a thermometer for the following properties.

It can measure a low temperature because its freezing point is low. (-115°C) but it can not measure higher temperature as its boiling point is low.
It can measure the temperature precisely because it has large expansion coefficient.
It’s expansion is regular.
Less hazardous.

Question 5.
Why hot substance does not remain as hot after two or three hours?
Answer:
A little heat is lost from around the lid and by a small amount of conduction through the vessel. So hot substance does not remain as hot after two or three hours.

Diagram based questions.

Observe the diagram and answer the given questions below it.

Question a.
What is the diagram about?
Answer:
The diagram is showing us the relation between density and convection.

Question b.
Why is the ice wrapped in wire gauze?
Answer:
Ice floats on water, to make it sink, it is wrapped in wire gauze.

Question c.
What does this experiment prove?
Answer:
When a liquid is heated, its density decreases and it rises upwards. This leads to the convection currents which makes the heated liquid rise upwards and cooler liquid takes it place.

Question a.
What is the diagram about?
Answer:
Expansion and contraction of a solid substance.

Question b.
Does the same thing happen in liquids and gases?
Answer:
Yes. Generally substances solids, liquids and gases expand on heating and contract on cooling.

Question c.
Give one example of this property in everyday life.
Answer:
Gaps are present in between two railway line track joints so that they do not bend due to expansion.

Question a.
Label parts 1 – 4
Answer:

Vacuum
metal/plastic jar
Spring
silvered surface of the glass.

Question b.
What is the principle of this object?
Answer:
As there is no medium in the vacuum between the two bottles, no transfer of heat takes place due to conduction and convection and radiated heat is reflected back by the shiny surface.

Question c.
State the uses of the given object.
Answer:
The temperature of substances inside it are maintained for some time. Hot things remain hot and cold things cold for 2 – 3 hours.

Question d.
What is an infrared camera?
Answer:
It is a camera which uses radiations to make our surroundings visible at night. Using this camera, it is possible to keep a watch on the movements of the enemy during the night.

Question e.
What is thermoware?
Answer:
Thermoware are object which do not allow heat to escape from them. So things stay warm in them. eg. hot pot, thermos flask.

7th Std Science Questions And Answers:

Nutrition in Living Organisms Class 7 Science Chapter 4 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 4 Nutrition in Living Organisms Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 4 Nutrition in Living Organisms Question Answer Maharashtra Board

Class 7 Science Chapter 4 Nutrition in Living Organisms Question Answer Maharashtra Board

1. Classify according to food-type.
Tiger, cow, vulture, bacteria, deer, goat, human, fungus, lion, sparrow, buffalo, frog, cockroach, tick.
Answer:

Carnivores: tiger, Lion
Herbivores: cow, deer, goat, buffalo
Scavengers: vulture
Decomposers: fungus, bacteria
Granivores: sparrow
Insectivores: frog Parasitic: tick
Omnivores: human, cockroach

2. Nutrition In Living Organisms Class 7 Exercise Match the pairs.

Class 7 Science Chapter 4 Nutrition In Living Organisms Question Answer Question 1.

Column ‘A’	Column ‘B’
1. Parasitic plant	a. Mushroom
2. Parasitic plant	b. Lichen
3. Saprophytic plant	c. Drosera
4. Symbiotic plant	d. Cuscuta

Answer:

Column ‘A’	Column ‘B’
1. Parasitic plant	d. Cuscuta
2. Parasitic plant	c. Drosera
3. Saprophytic plant	a. Mushroom
4. Symbiotic plant	b. Lichen

3. Answer the following questions in your words.

Question a.
Why do living organisms need nutrition?
Answer:
Living organisms need nutrition due to the following: (a) To supply the energy required for doing work, (b) For growth and development of the body, (c) To replace the damaged cells and repair tissues, (d) To fight diseases.

Question b.
Explain the process of production of food in plants.
Answer:
1. Green plants can produce their own food. With the help of sunlight and chlorophyll, plants make their own food in their leaves, using water and nutrients from the soil and carbon dioxide from the air.

2. This process is called as photosynthesis. In this process plants give out oxygen and take in carbon dioxide.

Question c.
What is meant by parasitic plants? Name their different types with examples of each.
Answer:
The plants that grow on the body of other plants to obtain food are called as parasitic plants.

There are two types of parasitic plants:

Holoparasites: e.g. Rafflesiaceae
Hemiparasites: e.g. Loranthaceae

Question d.
Explain the various steps of nutrition in animals.
Answer:
Steps of nutrition in animals are as follows:

Ingestion: Food is taken into the body.
Digestion: Conversion of food into simple soluble forms.
Absorption: Transfer of soluble food to the blood.
Assimilation: Utilization of absorbed food by cells and tissues for energy production, growth and repair.
Egestion: Removal of waste products and undigested food from body.

Question e.
Name some unicellular organisms in which all life processes take place within their unicellular body.
Answer:
Unicellular organisms like amoeba, euglena, paramoecium in which all life processes take place within their unicellular body.

4. Give reasons.

Question a.

Insectivorous plants are attractively coloured.
Answer:

Insectivorous plants generally grow in soil or water deficient in nitrogen compounds.
The plant body of the Drosera burmanii has a flower like appearance. It grows close to the ground. Even its leaves are attractively pink or red in colour with hairs at the margin.
Droplets of a sticky substances found on tips of the hairs attract insects.
These plants consume insects to fulfill their need for nitrogen. To attract the insects these plants are attractively coloured.

Question b.
Butterflies have a long tube-like proboscis.
Answer:
Holozoic mode of nutrition means the feeding of solid and liquid food by animals. Butterflies live on nectar from flowers. Therefore to suck the nectar from flowers, they have a long tube-like structure called proboscis.

5. Prepare and complete the flowchart according to type of nutrition.

Question a.
Prepare and complete the flowchart according to type of nutrition.

Answer:

6. Think and answer.

Question a.
We prepare a variety of foodstuffs and dishes at home. Are we then autotrophic organisms?
Answer:

We prepare a variety of foodstuffs and dishes at home but we are not autotrophic organisms.
In autotrophic organisms they have chlorophyll in their body and food is prepared here with help of sunlight, water and CO₂ for the organisms.
But the food which we prepare at home is not generated in our body.

Question b.
Which organisms are greater in number – autotrophs or heterotrophs? Why?
Answer:

Autotrophs have chlorophyll in the cell and here the organic food is prepared using sunlight, water and CO₂.
They do not depend on any other organism for survival.
But the heterotrophs depend on autotrophs and other organisms for survival. Hence autotrophs are more in number than heterotrophs.

Question c.
The number of heterotrophs found in desert regions is smaller. However, they are found in greater numbers in the sea. Why is this so?
Answer:

In desert region due to scarcity of water and excess heat, very few cactus are found as autotrophs compared to sea. As autotrophs are less, number of heterotrophs dependent on autotrophs are smaller.
Whereas in sea due to greater numbers of autotrophs, greater number of heterotrophs are found.

Question d.
What damage or harm do ectoparasitic and endoparasitic animals cause?
Answer:

Ectoparasitic animals suck the blood of the animal on which it remains and endoparasitic animals get readymade food from the body of animal in which it remain.
This way both the parasites make the animal weak by sucking their blood or by eating prepared food from them.

Question e.
Why is plant food not produced in any other parts of the plant except the green ones?
Answer:
Plant food is not produced in any other parts of the plant except the green ones because only green part contains chlorophyll and chlorophyll is very necessary for the production of food.

Class 7 Science Chapter 4 Nutrition In Living Organisms Project:

Question 1.
Many heterotrophic organisms live on one and the same plant. Observe one such plant in your neighborhood and find out about the heterotrophs that depend upon it for their food. Observe and make flotes about other organisms that use these heterotrophs as their food.

Question 2.
Prepare a Power point presentation on the topic ‘Nutrition in Living Organisms’.

Class 7 Science Chapter 4 Nutrition in Living Organisms Important Questions and Answers

Nutrition In Living Organisms Class 7 Exercise Fill in the blanks.

Nutrition In Living Organisms Class 7 Exercise Question 1.
Leaves have microscopic openings called ……………. .
Answer:
Stomata

Class 7 Science Chapter 4 Nutrition In Living Organisms Question 2.
In the process of photosynthesis plants take in ……………. and ……………. gas is given out.
Answer:
Carbondioxide, oxygen

Question 3.
The ……………. transports minerals and water from roots to all aerial parts of the plant.
Answer:
xylem

Question 4.
The ……………. transports the food from the leaves to other parts of the plant.
Answer:
phloem

Question 5.
Plants produce ……………. by the process of photosynthesis.
Answer:
Carbohydrates

Question 6.
……………. are made from carbon, hydrogen, oxygen.
Answer:
Carbohydrates

Question 7.
……………. are made from carbon, hydrogen and oxygen and nitrogen.
Answer:
proteins

Question 8.
……………. plants contain rhizobium micro-organisms.
Answer:
leguminous

Question 9.
Micro-organisms like ……………. are present in soil.
Answer:
azotobacter

Question 10.
Lichen is of a symbiosis between ……………. and ……………. .
Answer:
algae, fungi

Question 11.
The scientist ……………. identified Drosera plant in Sri Lanka in 1737.
Answer:
Johannes Burman

Question 12.
Fungi like mushroom and yeast are ……………. .
Answer:
saprophytes

Question 13.
Removal of waste products and undigested food from the body is called …………….
Answer:
Egestion

Question 14.
Amoeba moves with the help of ……………. .
Answer:
pseudopodia

Question 15.
Butterflies suck food with a tube like ……………. .
Answer:
proboscis

Question 16.
The ……………. or ……………. is an ant eating animal found in India.
Answer:
bobcat, udmanjar

Question 17.
Seed eating animals are called ……………. .
Answer:
granivores

Question 18.
Fruit eating animals are called ……………. .
Answer:
frugivores

Question 19.
Animals that obtain their food from both plants and animals are called ……………. .
Answer:
Omnivores

Question 20.
Roundworms are known as ……………. .
Answer:
endoparasites

Class 7 Science Chapter 4 Nutrition In Living Organisms Match the column:

Question 1.

Column ‘A’	Column ‘B’
1. Endoparasite	a. Vulture
2. Ectoparasite	b. Human
3. Seed eating animals	c. Tapeworm
4. Fruit eating animals	d. Bed bug
5. Scavenger	e. granivores
6. Omnivore	f. frugivores

Answer:

Column ‘A’	Column ‘B’
1. Endoparasite	c. Tapeworm
2. Ectoparasite	d. Bed bug
3. Seed eating animals	e. granivores
4. Fruit eating animals	f. frugivores
5. Scavenger	a. Vulture
6. Omnivore	b. Human

Say whether true or false, correct and rewrite the false statements.

Question 1.
Bed bug is an example of endoparasitic nutrition.
Answer:
False, Bed bug is an example of ectoparasitic nutrition

Question 2.
Spider shows saprozoic nutrition.
Answer:
True

Question 3.
The anteater is found in India.
Answer:
False. The anteater is found in Central and South America

Question 4.
Yellowing of leaves occur due to deficiency of iron.
Answer:
True

Question 5.
Mushroom is used in making bread.
Answer:
False. Yeast is used in making bread

Question 6.
Cuscuta is completely a parasitic plant.
Answer:
True

Question 7.
The nitrogen dioxide dissolves in rainwater and is converted into nitric acid.
Answer:
True

Question 8.
Micro-organism Rhizobium is found in soil.
Answer:
False. Micro-organism Azotobacter is found in soil.

Question 9.
Fixation of nitrogen occurs by biological and atmospheric methods.
Answer:
True

Question 10.
The chloroplasts present in the leaves contain chlorophyll.
Answer:
True

Question 11.
Decomposers obtain their food from living organisms.
Answer:
False, They obtain their food by decomposing the dead bodies of organisms or other materials

Question 12.
Carbondixode is given out during the process of photosynthesis.
Answer:
False, Oxygen is given out during the process of photosynthesis

Question 13.
Phloem transports the food from leaves to other parts of the plant.
Answer:
True

Question 14.
Carbohydrates are made up of carbon, hydrogen oxygen and nitrogen.
Answer:
False, Protein are made up of carbon, hydrogen, Oxygen and nitrogen.

Give scientific reasons.

Question 1.
Micro-organisms like Rhizobium are useful.
Answer:

Rhizobium micro-organisms are useful because plants cannot take gaseous nitrogen from air.
These micro-organisms absorb atmospheric nitrogen and convert it into its nitrate, a compound which is useful for plant.

Question 2.
Lichen is an example of a symbiotic nutrition.
Answer:
Lichen is a symbiosis between algae and fungi in which fungi provides water, minerals, as well as shelter to algae and in return the algae Master Key General Science (Std. 7), provide food to the fungi. So Lichen, is an example of symbiotic nutrition.

Question 3.
Drosera burmanii is an insectivorous plant.
Answer:
Drosera burmanii grows in a soil which has nitrogen deficiency. It feeds upon insects to obtain nitrogen, so it is an insectivorous plant.

Question 4.
Human is an omnivore.
Answer:
Humans obtain their food from both, plants and animals so human is an omnivore.

Question 5.
Tapeworm is an endoparasite.
Answer:
Tapeworm lives inside the body of other animals and obtain its food. So tapeworm is an endoparasite.

Question 6.
Decomposers are important for the ecosystem
Answer:
Decomposers feed on dead and decaying matter and therefore indirectly clean the ecosystem. If decomposers were not there then nutrients would not be able to return back and get recycled. Therefore decomposers are very important for the ecosystem.

Question 7.
Cuscuta is a total parasite while Loranthus is a partial parasite.
Answer:
Cuscuta is a nongreen yellow thread-like plant completely dependent on the host plant, loranthus is a partial parasitic because it can prepare its own food and it only takes water and minerals from the host plant.

Answer the following in your own words:

Question 1.

Classify the types of nutrients.
Answer:
There are two types of nutrients.

Nutrients like carbohydrates, proteins and fats are required in large quantity. These are macro-nutrients.
Minerals and vitamins are required in very small quantity. They are called micro-nutrients.

Question 2.
Explain the types of nutrition.
Answer:
There are two types of nutrition.

Some organisms can produce their own food and thus nourish themselves. This is called autotrophic nutrition.
Some organisms depend on other organisms, plants and animals for their food. This is called heterotrophic nutrition.

Question 3.
Write differences between xylem and phloem.
Answer:

xylem	Phloem
1. The xylem transports minerals and water from the root to all aerial parts of the plant.	1. The phloem transports the food (glucose) from the leaves to other parts of the plant where it is either consumed or stored.

Question 4.
What is chemosynthesis? Which plants produce their food by chemosynthesis?
Answer:

Chemosynthesis is the biological conversion of one or more carbon-containing molecules and nutrients into organic matter.
It uses the oxidation of inorganic compounds or methane as a source of energy rather than sunlight.
Sulphur bacteria and nitrosomonas produce their food by chemosynthesis.

Question 5.
Name the micro-organisms which help in biological fixation of nitrogen. How?
Answer:
Two different types of micro-organisms can bring about biological nitrogen fixation.

Root-nodules of leguminous plants contain the micro-organism rhizobium. These micro-organisms absorb atmospheric nitrogen and convert if into its nitrate, a compound.
Micro-organisms like azotobacter are’present in soil. They also convert atmospheric nitrogen into nitrates.

Question 6.
What is symbiotic nutrition? Give one example of it.
Answer:

Two or more than two different types of plant live together to fulfill their needs of nutrition, protection, support etc. with each other’s help. This type of nutrition is called symbiotic nutrition.
e.g. Lichen is an example of symbiosis between algae and fungi.

Question 7.
Write about Drosera burmanii.
Answer:

It is art insectivorous plant.
The scientist Johannes Burman identified this plant in Sri Lanka in 1737. Hence, the plant is named after him.
It grows close to the ground.
Its leaves are attractively pink or red in colour with hairs at the margin.
Droplets of a sticky substance found at the tips of the hairs attract insects.
It grows in a place where deficiency of nitrogen in the soil. To get nitrogen for its growth, it eats insects.

Question 8.
What are called saprophytic plants? Give Examples.
Answer:
Plants which obtain the food from dead and decaying bodies of other organisms are called saprophytic plants e.g. Yeast and mushrooms.

Question 9.
Classify the animals according to the type of food they eat.
microbes, vulture, monkey, tiger, lion, goat, cow, buffalo, crow, hyena, human, chimpanzee
Answer:

Herbivores: goat, cow, buffalo.
Carnivores: tiger, lion
Omnivores: monkey, human, chimpanzee
Scavengers: vulture, crow, hyena
Decomposers: microbes

Explain the terms:

Herbivores: Animals that depend on plants only for their food are called Herbivores.
Carnivores: Animals that depend on other animals for their food are called Carnivores.
Granivores: Animals that eat grains (seed) are called Granivores.
Frugivores: Animals that eat fruits are called frugivores.
Omnivores: Animals that obtain their food from both plants and animals are called omnivores.
Scavengers: Animals that obtain their food from dead bodies of animals are called Scavengers.
Decomposers: Microbes which obtain their food by decomposing the dead bodies of organisms or other materials are called decomposers.
Ectoparasitic nutrition: Some animals live on the body surface of other animals and obtain their food by sucking their blood. This is called ectoparasitic nutrition.
Endoparasitic nutrition: Some animals live inside the body of other animals and obtain their food. This is called endoparasitic nutrition.
Symbiotic nutrition: In some cases, two or more than two different types of plants live together to fulfill their needs of nutrition, protection, support etc. with each other’s help. This type of nutrition is called symbiotic nutrition.

Write the role of different nutrients like nitrogen, phosphorus, potassium,magnesium, Iron, manganese and zinc and effects of their deficiency on plants.

Question 1.
Write the role of different nutrients like nitrogen, phosphorus, potassium, magnesium, Iron, manganese and zinc and effects of their deficiency on plants.
Answer:
Role of nutrients and effects of their deficiency on plants:

Nutrients	Function	Effects of deficiency
Nitrogen	Important components of proteins, chlorophyll and cytoplasm.	Retarded/stunted growth, yellowing of leaves.
Phosphorus	Conversion of light energy into chemical energy.	Early leaf-fail, late flowering, slow growth of roots.
Potassium	Necessary for metabolic activities.	Weak stem, wilting of leaves, failure to produce carbohydrates.
Magnesium	Production of chlorophyll	Slow/retarded growth, yellowing of leaves.
Iron	Production of chlorophyll	Yellowing of leaves
Manganese	Production of main plant hormones	Retarded growth, spotted leaves
Zinc	Production of hormones and their intermediates	Retarded growth, yellowing of leaves

Can you tell?

Answer the following question:

Question 1.
How does ingestion occur in unicellular animals like amoeba?
Answer:

Amoeba does not have organs like hands and mouth.
It is a unicellular animal. It can take in food through any part of the surface of its unicellular body.
It surrounds the food particle from all sides to take it into the cell.
After that it digests the food with the help of different enzymes.
Undigested food is left behind as the amoeba moves further with the help of pseudopodia.
In unicellular animals like amoeba, euglena, paramoecium,. etc. all the steps of nutrition occur within their unicellular body.

Question 2.
How do plants produce their own food?
Answer:
Green plants produce their own food with the help of sunlight, chlorophyll, water, nutrients from soil and carbon dioxide from the air. This process is called as photosynthesis

Use your brain power!

Answer the following questions:

Question 1.
Write the uses of yeast and mushrooms.
Answer:
Yeast is used in fermentation processes and making bread.
Mushrooms are a rich source of vitamins and iron.

Question 2.i
Which part of the loranthus plant carries out photosynthesis?
Answer:
Leaves of the loranthus plant carries out photosynthesis.

Question 2.ii
From where do they obtain minerals and water?
Answer:
They obtain water and minerals from the xylem and phloem of the other host plant.

Question 2.iii
Why is loranthus known as a partially parasitic plant?
Answer:
Loranthus is known as partially parasitic plant because it does photosynthesis with the help of leaves but only for water and minerals it depends on other plants.

Question 3.
Why does the pitcher plant feed on insects even though it produces food by photosynthesis?
Answer:
Pitcher plants grow in a place where soil has deficiency of nitrogen compounds so to fulfill the need of nitrogen they feed on insects.

Observe the diagram and answer the following questions.

Question a.
Name the process shown in the picture.
Answer:
The process shown is photosynthesis.

Question b.
Which type of plants use the above process for their nutrition?
Answer:
Autotrophic plants (green plants) use the above process for their nutrition.

Question c.
What is the pigment in the leaf that helps in the above process?
Answer:
Chlorophyll

Question d.
Give the chemical equation of the above process?
Answer:

Question e.
What is the importance of this process to living things?
Answer:
Photosynthesis helps the plants to prepare their own food and also store it in their plant bodies. Animals depend upon this stored food for their nutrition.
During photosynthesis, oxygen is given out which is important for all living organisms for respiration.

Observe the diagram and answer the following questions.

Question a.
What is shown in the picture?
Answer:
Roots of leguminous plants having root nodules.

Question b.
What is the importance of these types of plants?
Answer:
These types of plants help to provide nitrogen to the soil.

Question c.
What is the process called?
Answer:
Biological Nitrogen fixation

Question d.
Explain the process.
Answer:
Root nodules of leguminous plants contain Rhizobium micro-organisms. These micro¬organisms convert atmospheric nitrogen into nitrates. Thus the soil becomes rich in nitrogen.

7th Std Science Questions And Answers:

Changes – Physical and Chemical Class 7 Science Chapter 13 Questions And Answers Maharashtra Board

January 4, 2025January 3, 2025 by Bhagya

Balbharti Maharashtra State Board Class 7 Science Solutions Chapter 13 Changes – Physical and Chemical Notes, Textbook Exercise Important Questions and Answers.

Std 7 Science Chapter 13 Changes – Physical and Chemical Question Answer Maharashtra Board

Class 7 Science Chapter 13 Changes – Physical and Chemical Question Answer Maharashtra Board

1. Distinguish between the following.

Question a.
Physical change and Chemical change
Answer:

Physical changes	Chemical changes
1. In a physical change material may change its	1. A change which after physical properties and
shape, size, texture or state.	composition also.
2. No new compound is formed.	2. New compound /substance is formed due to chemical change.
3. The change is temporary. It is reversible.	3. The change is permanent and irreversible.
4. Examples: Evaporation of water, boiling of water, melting of ice.	4. Examples: Burning of wood, paper, souring of milk, digestion of food, rusting of iron.

Question b.
Periodic changes and Non-periodic change
Answer:

Periodic changes	Non-periodic change
1. Some changes occur again and again after a definite interval of time. Such changes are called periodic changes.	1. In this, certain changes will recur after one occurrence, it cannot be said for sure, even if they occur interval is not fixed. Such changes are called non-periodic changes.
2. Examples: movement of clock hands in clock showing time, change of season, day and night formation, heart beat, ripening of fruit, rising and setting of the sun.	2. Examples: volcanic eruption, occurrence of an earthquake, tsunami, forest fires, freezing of water to form ice, sneezing, rusting of iron.
3. They repeat themselves after a fixed interval of time.	3. They do not repeat themselves after a fixed interval of time.

Question c.
Natural change and Man-made change
Answer:

Natural change	Man-made change
1. Changes that occur naturally on its own are called natural changes.	1. Changes that are result of human activity. Such changes are called man-made.
2. Examples ripening of a fruit, spoiling of milk, change in the climate	2. Burning of fossil fuels, deforestation, pollution of air, water and soil.

2. Under which different types can the following changes be classified?

Question a.
Conversion of milk into yoghurt.
Answer:
Manmade (useful).

Question b.
Bursting of cracker.
Answer:
Manmade (fast change).

Question c.
Occurrence of an earthquake.
Answer:
Non-periodic.

Question d.
Revolution of earth around the sun.
Answer:
Periodic. (Natural change)

Question e.
Stretching of a spring.
Answer:
Physical, reversible change.

3. Give reasons.

Question a.
While purchasing canned food, its expiry date should be checked.
Answer:

Canned food is processed food.
After certain period of time it may get spoilt due to some growth of micro-organism it may get intoxicated.
If we consume such food we may get food poisoning, so we should check the expiry date.

Question b.
An iron article should be given a coat of paint.
Answer:

When an iron article is kept for long time it gets corroded due to presence of oxygen in atmosphere.
Iron gets oxidized to iron oxide which forms a reddish brown layer on it and iron gets rusted.
It is called corrosion. Due to corrosion things become weak.
So an iron article should be given a coat of paint so that it is protected against corrosion.
Paint gives protection to iron.

Question c.
A Wooden article should be polished.
Answer:

When a wooden article comes in contact with moisture there is possibility of fungal growth and also termites will make wooden article brittle and break.
So a wooden article should be polished which forms a protective layer.
It does not allow the wooden article to get decayed by moisture or attacked by termite.

Question d.
Copper and brass utensils should be tinned.
Answer:

Due to corrosion of copper or brass a greenish layer is seen to form on it.
So to protect copper and brass utensils from corrosion they are coated with tin.
This process is called thinning.

Question e.
A dry handkerchief gets wet at once on dipping in water, but it takes long for a wet handkerchief to dry.
Answer:

The dry fibres of handkerchief absorbs water to its maximum capacity immediately that is why handkerchief gets wet at once.
When wet handkerchief dries, all the water absorbed has to become water vapour by evaporation.
This depends on surrounding air and heat.
That is why wet handkerchief takes a long time to dry.

4. What will you take into account while identifying the following:

Question a.
A physical change in a substance.
Answer:
I will take into account the following facts.

Whether the shape, size or state of the substance is changed.
Whether it is a temporary change.
Whether it is a reversible change.

Question b.
A chemical change in a substance.
Answer:
I will take into account the following facts.

Whether a new substance is formed.
Whether it is a permanent change.
Whether it is a non-reversible change.

5. Read the paragraph and note down the various types of changes it mentions.

Question a.
Read the paragraph and note down the various types of changes it mentions.
It was nearing six o’clock in the evening. The sun was setting. A breeze was blowing. Leaves on the tree were shaking. Sahil was sitting in the courtyard, rolling balls of wet soil and shaping them into various toys. Then he felt hungry and went into the house. Mother made a dough from wheat flour and fried purees. While eating hot purees, his attention was drawn outside the window. It had started raining. There was lighting too. Sahil was enjoying his dinner in the dim light.
Answer:

Clock showing six o’clock time – It is a periodic change.
Sun was setting – A periodic change.
Breeze was blowing – A natural change.
Leaves shaking – A natural change.
Making toys from wet soil – Physical change.
Making dough from wheat flour – Physical change
Frying purees – Chemical change.
Raining – Natural change.
Lightning – Natural change.

Project:

Question a.
Visit a place where work like powder coating. spray painting is done. Make a note of the information you obtain.

Class 7 Science Chapter 13 Changes – Physical and Chemical Important Questions and Answers

Fill in the blanks and rewrite the sentences:

Question 1.
Burning of candle is a ………………. change.
Answer:
chemical

Question 2.
Cooking of vegetable is ………………. change.
Answer:
useful

Question 3.
A man painted his main gate made up of iron to prevent it from ………………. .
Answer:
rusting

Question 4.
Galvanization is a process used to prevent the rusting of ………………. .
Answer:
iron

Question 5.
Making sugar solution is a ………………. change.
Answer:
physical

Question 6.
A physical change is generally ………………. .
Answer:
temporary

Question 7.
Grinding of wheat grain changes its size, it is a ………………. .
Answer:
physical change

Question 8.
Iron benches kept in lawns and gardens get rusted. It is a change because a new ………………. is formed.
Answer:
chemical, product.

State whether the following statements are True or False. Correct and rewrite the false statement:

Question 1.
Iron and rust are the same substance.
Answer:
False, Rust is oxide of iron.

Question 2.
Iron pipes coated with zinc do not get rusted easily.
Answer:
True

Question 3.
Formation of manure from leaves is a physical change.
Answer:
False, it is a chemical change.

Question 4.
Cutting a log of wood into pieces is a chemical change.
Answer:
False, it is a physical change.

Question 5.
Digestion of food is a chemical change.
Answer:
True

Question 6.
Melting of wax is a chemical change.
Answer:
False, it is a physical change.

Question 7.
Dissolving sugar in water is physical change.
Answer:
True

Question 8.
Changes in which new substances are formed are called physical changes.
Answer:
False, they are called chemical change.

Question 9.
Breaking down of larger food particles into smaller particles is a chemical change.
Answer:
False, it is a chemical change.

Question 10.
Setting of curd is a physical change.
Answer:
False, it is a chemical change.

Question 11.
Heating of iron is a physical change.
Answer:
True

Question 12.
Cooking a vegetable is chemical change.
Answer:
True

Question 13.
Freezing water into ice is a chemical change.
Answer:
False, it is a physical change

Define the following.

Question 1.
Physical change:
Answer:
In a physical change the material may change shapes or forms but no new compounds are formed and change can generally be reversed by reversing the conditions.

Question 2.
Chemical change
Answer:
A chemical change produces a new substance having new and different properties and which cannot be reversed by reversing the conditions.

Question 3.
Periodic change
Answer:
Some changes occur again and again after . a definite interval of time, such changes are called periodic changes.

Question 4.
Non-periodic change
Answer:
Changes that do not repeat themselves after a fixed interval of time are called non-periodic changes.

Question 5.
Reversible change
Answer:
The changes that can occur in a forward and reverse direction again and again are called reversible changes.

Question 6.
Irreversible change.
Answer:
The changes which we cannot reverse back to same thing are called Irreversible changes e.g. Burning of wood, paper.

Question 7.
Condensation
Answer:
The process by which matter changes from its vapour or gaseous state into its liquid state by cooling is called condensation.

Question 8.
Corrosion of metals
Answer:
When an iron article rusts, a reddish brown layer (of iron oxide) forms on it. A greenish layer is seen to form on a copper article. This is called corrosion of metals.

Question 9.
Galvanization
Answer:
Iron articles are given a thin coat of zinc to prevent corrosion this is called galvanization.

Question 10.
Tinning
Answer:
Copper and brass articles are coated with tin. This is called tinning.

Question 11.
Natural change
Answer:
Changes that occur naturally like ripening of a fruit, spoiling of milk are called natural changes.

Question 12.
Man-made change
Answer:
Man-made changes are result of human- activity. E.g. Burning of fossil fuel.

Question 13.
Useful change
Answer:
Many changes such as baking bread, cooking food are useful to us, they are called useful changes.

Question 14.
Harmful change
Answer:
The changes that are not useful or changes that harms living things or the environment are called harmful changes.

Name or Give two example of:

Question 1.
Two physical changes.
Answer:

Melting of wax
Melting of ice

Question 2.
Two chemical changes.
Answer:

Burning of wax candle
Burning of wood or paper.

Question 3.
Two periodic changes.
Answer:

Occurrence of day and night
change of seasons

Question 4.
Two non-periodic changes.
Answer:

A meteor moving across the sky.
A bird sitting on a tree flies away.

Question 5.
Two reversible changes.
Answer:

Melting of wax.
Freezing water into ice.

Question 6.
Two irreversible changes.
Answer:

Ripening of a mango.
Burning of wood

Question 7.
Two natural changes.
Answer:

Lighting in the sky.
Earthquake.

Question 8.
Two manmade changes.
Answer:

Baking bread
Cooking food.

Question 9.
Two useful changes.
Answer:

Ripening of mango
Curdling of milk.

Question 10.
Two harmful changes.
Answer:

Spoiling of milk.
Air pollution.

Match the following:

Question 1.

Column ‘A’	Column ‘B’
1. Photosynthesis	a. Physical change.
2. Dissolving sugar in water	b. Chemical change
3. Burning of wood	c. Man-made change.
4. Melting of wax	d. Periodic changes.
5. Digestion of food	e. Non-periodic change
6. Heartbeat	f. Chemical change.
7. Occurrence of earthquake.	g. Physical change.
8. Deforestation	h. Chemical change.

Answer:

Column ‘A’	Column ‘B’
1. Photosynthesis	b. Chemical change
2. Dissolving sugar in water	a. Physical change.
3. Burning of wood	f. Chemical change.
4. Melting of wax	g. Physical change.
5. Digestion of food	h. Chemical change.
6. Heartbeat	d. Periodic changes.
7. Occurrence of earthquake.	e. Non-periodic change
8. Deforestation	c. Man-made change.

Question 2.

Column ‘A’	Column ‘B’
1. Depositing a layer of zinc on Iron	a. Tinning
2. Souring of milk	b. Rust
3. Curdling of milk	c. Galvanization
4. Iron oxide	d. Chemical changes
5. Depositing layer of tin on copper and brass article.	e. Man-made changes.

Answer:

Column ‘A’	Column ‘B’
1. Depositing a layer of zinc on Iron	c. Galvanization
2. Souring of milk	d. Chemical changes
3. Curdling of milk	e. Man-made changes.
4. Iron oxide	b. Rust
5. Depositing layer of tin on copper and brass article.	a. Tinning

Distinguish between the following.

Question 1.
Reversible change and Irreversible change
Answer:

Reversible change	Irreversible change
1. The changes that can occur in a forward and reverse direction again and again is called reversible.	1. The changes which we can not reverse back to some thing are called irreversible change.
2. E.g.: (a) Melting a wax candle and obtaining the original solid wax again, (b) Stretching a rubber or spring.	2. E.g.: Burning of paper or wood cannot be undone. Wood cannot be obtained from the ash.

Under which different types can be following changes be classified:

Question 1.
Formation of curd from milk.
Answer:
Manmade change (useful), chemical

Question 2.
Burning of wood or paper.
Answer:
Manmade, chemical change.

Question 3.
Glowing of bulb.
Answer:
Manmade (fast).

Question 4.
Rusting of iron.
Answer:
Chemical change (harmful)

Question 5.
Burning of Camphor.
Answer:
Chemical change

Question 6.
Souring of milk.
Answer:
chemical change (harmful)

Question 7.
Digestion of food.
Answer:
Chemical change (useful), irreversible

Question 8.
Change of season.
Answer:
Periodic change, natural change

Question 9.
Day and night formation.
Answer:
Periodic change

Question 10.
Heartbeat.
Answer:
Periodic change

Question 11.
Water pollution.
Answer:
Manmade, harmful change

Question 12.
Air pollution.
Answer:
Manmade, harmful change

Question 13.
Burning of fossil fuel
Answer:
Manmade (irreversible change)

Question 14.
Ripening of fruit.
Answer:
Natural, chemical

Question 15.
Change-in climate.
Answer:
Natural, periodic

Question 16.
Melting of ice into water
Answer:
Physical change

Question 17.
Germination of seed.
Answer:
Natural, slow, desirable.

Question 18.
Bursting of balloon.
Answer:
Irreversible change (fast).

Give reasons:

Question 1.
The burning of wax is a chemical change
Answer:

Because when the cotton wick embedded in the candle is burnt, ash and smoke is formed.
It is not possible to make wick again from the smoke and ash.

Can you tell?

Answer the following questions:

Question 1.
We see many man-made materials in our day-to-day life. For what purpose are they produced.
Answer:
We see many man-made matrical in our day to day life. For example,

Air conditioners for getting cool air in houses offices and cars.
Wooden furniture made from wood obtained by cutting trees.
Refrigerators to protect food from spoiling.

Question 2.
You made a link from the glass piece. How will you change the shape of the link to give it its original shape?
Answer:
Heat the glass piece again at the link. When it becomes soft break it.

Question 3.
How will you restore the original candle after melting one ?
Answer:
Collect the melted wax and give the required shape when it is soft.

Question 4.
What comes after daytime?
Answer:
Night time (periodic change)

Question 5.
What is the next stage after sunrise?
Answer:
Sunset (periodic change)

Question 6.
What comes after a high tide in the sea?
Answer:
Low tide (periodic)

Question 7.
A bird sitting on a tree flies away.
Answer:
non-periodic change.

Question 8.
A meteor streaking across the sky.
Answer:
non-periodic change.

Use your brainpower!

Answer the following questions:

Question 1.
What kind of change is the falling of a tree in a storm?
Answer:
Natural change.

Question 2.
What kind of a change is the conversion of milk into yoghurt?
Answer:
Manmade ‘ change, useful change and a chemical change

Question 3.
What is meant by irreversible change? Give some examples.
Answer:

An irreversible change is a permanent change that cannot be undone, cannot reverse it back to original substance.
In irreversible change new materials are always formed.
Irreversible changes are permanent changes.
Heating, burning, mixing, powdering are few processes which causes irreversible changes.

Examples:

burning of paper or wood
cooking of raw egg.

Question 4.
Which type of change is the change of seasons from summer to rains to winter?
Answer:
Natural and periodic change

Question 5.
Which hands of a clock show periodic changes from 6.00 am to 6.00 pm? How many times?
Answer:
Small (hour) hand (12 times).

Question 6.
Which of the following are physical changes and which are chemical changes?
(making a table from wood, burning wood, breaking of a glass object, ripening of a tomato, rusting of iron.
Answer:

Physical	Chemical
1. Making a table from wood	1. Burning wood
2. Breaking of a glass object	2. Rusting of iron
	3. Ripening of a tomato

Question 7.
What are periodic and non-periodic changes?
Answer:
1. We find that some changes occur again and again after a definite interval of time. Such changes are called Periodic changes, e.g. Sunrise and Sunset.
2. On the other hand, it cannot be ‘Slid for sure when certain changes will recur after one occurrence. Even if they recur, the time interval is not fixed. Such changes are called non-periodic changes, e.g. A meteor streaking across the sky.

Question 8.a.
Which changes shown in the pictures below are temporary.

Answer:
(b) Removing iron nails with help of magnet
(d) Conversion of ice cubes into water.

Question b.
Which of the changes are permanent?
Answer:
Bud blooming into flower.

Question c.
In which did the original matter undergo a change?
Answer:

In permanent change
Bud blooming into flower.

Question d.
In which the original matter remain unchanged?
Answer:
In temporary changes
(b) iron nails
(d) ice cubes.

Question e.
In which of the changes was a new substance with a new property formed?
Answer:

Bud blooming into flower.
Ice to water, Ice is in solid state, Water is in liquid state.

Question 9.
Give some examples of fast and slow changes that occur in your surroundings.
Answer:

Fast	Slow
1. Burning of paper or wood	1. rusting of iron
2. Burning of candle	2. germination of seeds
3. Bursting of a balloon	3. curdling of milk
4. Bursting of crackers	4. ripening of a fruit

7th Std Science Questions And Answers: