NCERT Solutions for class 10 Science Chapter 14:Sources of Energy

NCERT Solutions for class 10 Science Chapter 14 Exercise Question

Question 1

A solar water heater cannot be used to get hot water on
a. A sunny day
b. A cloudy day
c. A hot day
d. A windy day

Answer

b) A cloudy day

Question 2

Which of the following is not an example of a bio-mass energy source?
a. Wood
b. Gobar-gas
c. Nuclear energy
d. Coal

Answer

c) Nuclear energy

Question 3

Most of the sources of energy we use represent stored solar energy. Which of the following is not ultimately derived from the sun’s energy?
a. Geothermal energy
b. Wind energy
c. Nuclear energy
d. Bio-mass

Answer

c) Nuclear energy

Question 4

Compare and contrast fossil fuels and the sun as direct sources of energy.

Answer

fossil fuels are obtained from deep under Earth’s crust. fossil fuels are the direct source of energy. But these are limited in amount also they are non-renewable and cannot be replenished

Solar energy is abundant in nature and can be replenished and also a direct source of energy . Solar energy is available in unlimited amount So it is renewable source of energy.

Question 5

Compare and contrast bio-mass and hydroelectricity as sources of energy.

Answer

Bio-mass is is a renewable source of energy and it is obtained from the dead plants and animals wastes. Examples wood, gobar-gas.

Hydroelectricity is obtained from the potential energy of the stored water at a some height.So we generator electricity. Dams and reservoirs are used in hydroelectricity.Both bio-mass and hydroelectricity sources can be obtained again and again.

Question 6

What are the limitations of extracting energy from:
a. The wind?
b. Waves?
c. Tides?

Answer

a) The wind:windmills are used wind to convert energy .Its limitations is windmills need more than 15 km/h speed of wind to generate electricity. And it requires a long time to get a significant amount of energy and wear and tear of windmill parts is quite high.

b) Waves:Wave energy can only be used in areas where Waves are very strong.It setup cost is very high.

c) Tides: Very strong ocean waves are required in order to produce energy from waves .The height of tidal waves limit the production of tidal energy.

Question 7

On what basis would you classify energy sources as:
a. Renewable and non-renewable?
b. Exhaustible and inexhaustible?

Are the options given in (a) and (b) the same?

Answer

a) Renewable and non-renewable:
A renewable resource that can be used repeatedly and does not run out because it is naturally replaced and easily available in nature. Like solar energy, tidal energy, wind energy, bio-mass.

Non-renewable energy sources are those which do not restore on their own and have limited amount in nature. Like fossil fuels which includes petroleum, coal and natural gas.

b) Exhaustible and inexhaustible:
Exhaustible resources can be also called non - renewable resources and it can be deplete after few hundred years. Like coal and petroleum.

Inexhaustible source can be also called renewable resource its present unlimited in nature and do not deplete Like solar, wind energy and tidal energy.

Question 8

What are the qualities of an ideal source of energy?

Answer

The qualities of an ideal source of energy are follow:

Its cost is very low

It should be easily available

It should be Pollution free

Easy transportation and storage

It has a high calorific value.

easy to handle.

Question 9

What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?

Answer

Advantages:

solar cooker need sunlight. It is a clean renewable source of energy and its is available in unlimited amount of free energy.

Disadvantages:

In cloudy day it doesn’t work as it need sunlight for work and its manufactur cost is also very high .

Question 10

What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption?

Answer

The demand of energy is increased due to the industrialisation all over the world. Their energy demands are fulfilled by energy obtained from fossil fuels. Due to their harsh usage its harm the environment by releases large amount of carbon dioxide which led greenhouse and results in global warming. So we should use these resources in optimum.we need to reduce the unnecessary usage of electricity and water. We should not waste the energy. We should use alternate source of energy such as solar energy.