NCERT Solutions Class 10 Science Chapter 14

NCERT Solutions for Class 10 Science Chapter 14 – Sources of Energy 

Chapter 14 of Class 10 Science is about the Sources of Energy. It is a critical chapter from the perspective of CBSE Class 10 Board Examinations. An in-depth understanding of this chapter will increase your chances of scoring good marks. 

Extramarks is one of the best online learning platforms for students because it has a repository of study materials for them to maximize their potential. . Our academic research team has prepared the study materials based on the latest NCERT textbooks and as per the CBSE  guidelines to help students learn and understand the concepts easily. Lakhs of students have trust and faith in  Extramarks study materials to score high grades in their exams. Extramarks is a one stop solution to all your problems.

NCERT Solutions for Class 10 Science Chapter 14, provided by Extramarks, is developed by subject matter experts to help students understand the concepts of energy and its sources clearly and build a strong foundation for higher classes as these chapters are graded and require prerequisite knowledge.. 

Students can also prepare well for competitive examinations like Olympiads by referring to these solutions on Extramarks. Concepts like types of energy sources, good sources of energy, conventional and non-conventional sources of energy, and more are all well explained in the key topics covered under NCERT Solutions for Class 10 Science Chapter 14.

Key Topics Covered In NCERT Solutions for Class 10 Science Chapter 14

Here is a summary of the key topics covered in Chapter 14 of Class 10 Science. 

Students are encouraged to refer to our NCERT Solutions for Class 10 Science Chapter 14 in which our subject experts  have  explained each topic at a greater length. Students will learn with interest and find it easy to memorise. Solutions in a way also guide how to answer questions without making careless slips. It makes them confident and that itself reduces their anxiety and stress to a great extent. Hence it becomes easier for students to score well in the examinations.

Good Sources of Energy

Energy is the most vital element of our daily lives. A good energy source can provide excellent and valuable energy at a stable rate over a long period. 

 The characteristics of good sources of energy are listed below:

  1. Safe and suitable to use.
  2. Does enormous work per unit of mass.
  3. Produces a lot of heat per unit of mass.
  4. Easy to store and transport.
  5. Inexpensive and accessible.
  6. Environment-friendly i.e. produces less amount of smoke and residue.

Categories of Sources of Energy:

Sources of Energy can be categorized in two ways:

  • Renewable and Non-Renewable Sources of Energy.
  • Conventional sources of Energy and Non-Conventional sources of energy.

Each of the above categories is explained well in our NCERT Solutions for Class 10 Science Chapter 14. NCERT solutions help students be confident and improve their learning abilities to understand those complex topics with ease and prepare well for the examinations to get excellent results.

Renewable and Non-Renewable Sources of Energy

Renewable sources are those which are inexhaustible. Energy can be replaced and used again and again without any limit. They are naturally available in abundance free of cost and generated in a short period. We can ensure a steady supply of energy at a constant pace if we manage biomass by replacing the trees we cut down for firewood. Examples of  renewable  sources of  energy include:

  1. Solar Energy.
  2. Wind energy.
  3. Water energy (hydro-energy).
  4. Geothermal Energy.
  5. Ocean energy.
  6. Biomass energy (firewood, animal dung, and biodegradable waste from cities and crop residues constitute biomass).

Non-Renewable Sources are those which are exhaustible. These energies cannot be replaced once they are used. These sources were generated or accumulated in nature over millions of l years by dead cells of plants and animals called Fossil fuels. Due to their immense use and limited availability, these sources are getting exhausted at a fast pace in today’s world. It is tough to find and utilise the new deposits of these sources. Also, non-renewable sources cause more pollution in the environment. 

Examples of non-renewable sources of energy are fossil fuels like:

  1. Coal.
  2. Oil.
  3. Natural gas.

 Both renewable and non-renewable energy sources are illustrated with examples and explained in detail in our NCERT Solutions for Class 10 Science Chapter 14 which students can only access by registering on Extramarks’ website.

Conventional Sources Of Energy

Following are the conventional sources of energy that have been used broadly since ancient times to meet our energy requirements are given below:

  1. Fossil Fuels (Coal, Oil, natural gas):

Fossil fuels are the remains of primitive plants and animals buried deep inside the earth millions of years ago due to some natural processes.  The organisms or its parts get buried in sand or mud in the formation process.  Then they decay and disintegrate gradually, leaving no signs of their existence. 

Due to extreme pressure and temperature on the earth, these get converted into fossil fuels. The process is referred to as fossilization. These are non-renewable and cause environmental problems due to pollution.

  1. Hydro Energy (Hydro Power Plant):

In this, the flowing river water is stored in a high-rise dam, and later the water is allowed to fall with great force from the top of the dam on the turbines. These turbines are connected to electric generators, which generate electric currents and hence, the electricity produced by using the energy of falling water is called hydroelectricity or hydel power. 

This process is also described as converting the potential energy of water into kinetic energy and then into electric energy.

The process of generating electricity using a hydropower plant is shown below. A more detailed  explanation can be found in our NCERT Solutions for Class 10 Science Chapter 14

Advantages of Hydro Power Plant: 

  • It is abundantly available free of cost and is the most conventional and renewable energy source.
  • It’s clean energy which has less impact on environmental pollution as compared to other forms of energy.

Disadvantages of Hydro Power Plant: 

  • High cost involved in the construction.
  • Dams cannot be constructed on all river sites.
  • Vast areas of human residence and agriculture fields get engulfed.
  1. Biomass Energy:

Biomass is the organic matter of dead plants, trees, animals, agricultural waste, sewage, poultry dropping, and cow dung used as fuel to produce energy. It is a renewable and conventional source of energy. 


During the decomposition of biomass components in the absence of oxygen(Anaerobic Respiration), a mixture of gases is produced called Bio-gas. The picture given below illustrates the process of producing biogas in a biogas plant.

Biogas comprises 75% methane,  25% CO2, and traces of nitrogen and hydrogen gases.

Advantages of Biogas: 

  • The biogas plant is simple and easy to build in rural areas.
  • The fuel does not leave smoke or ashes while burning.
  • The main component of biogas, i.e., Methane, is a high-value calorific fuel.
  • The consumed slurry forms good manure rich in nitrogen and phosphorus. 
  • Deforestation is reduced.
  1. Wind Energy:

Moving air is called wind. Air blows due to the uneven heating of the earth. Wind energy is produced from the air blowing at a high speed. With the use of windmills, the blowing air is leveraged to turn the wind turbines which in turn generate electricity. The surface of the earth would always have uneven heating, so wind energy would also be available forever.

Wind’s kinetic energy is used in the running of windmills, water lifting pumps, flour mills, fly engines, fewer airplanes, or gliders in the air to generate electricity.


  • Renewable energy and it’s cost-effective.
  • Wind energy is a green energy source and does not cause pollution and it’s  eco-friendly


  • They aren’t aesthetically pleasing, and there are limited locations suitable for wind turbines.
  •  It requires a large area to install the windmills.
  • Wind speed is not always uniform, and is quite unpredictable, and the output result is less than the investment.

Different forms of energy sources, their advantages and disadvantages, and their applications in our day-to-day life are covered in our NCERT Solutions for Class 10 Science Chapter 14.

Non-Conventional Sources of Energy

Non-Conventional Sources of Energy are not so widely used or used on a limited scale to meet our energy requirements.  Here are some examples:

  1. Solar Energy:

It is a renewable source produced by the sun in the form of heat and light. Photovoltaic cells(solar cells) convert solar radiation directly into electricity. 

Solar cells are organized on large flat sheets to form a mirror solar panel. Solar devices are painted black from the outside and a large glass plate traps solar radiation and the greenhouse effect.


  • Renewable.
  • Eco-friendly.


  • Silicon cells are costly.
  • Solar devices cannot be used at night or on cloudy days.
  • Solar radiations are not uniform, and a maximum of only 100 degrees Celsius temperature can be achieved.
  1. Geothermal Energy:

The Energy utilized from the heat of the sun is called geothermal energy. It is the naturally occurring thermal energy of the earth found in the rocks and the fluid trapped within those rocks. 

The rocks and hot gases called magma are formed when the heat melts the rocks. This magma is accumulated deep within the earth’s surface forming hot spots. Electricity is generated due to the underground water making contact with these hot spots and changing into steam.


  • Inexpensive.
  • Renewable


  • Fewer sites are available for harnessing energy.
  1. Ocean Energy:

Oceans acquire 71% of the earth. Ocean water can be used as a renewable source of energy in the following ways:  

  • Ocean Thermal Energy
  • Ocean Tidal Energy
  • Sea Wave Energy
  • Energy from Nuclear Deuterium of Oceans
  • Energy From Salinity Gradient in Seas
  • Energy From Sea Vegetation or Biomass
  1. Nuclear Energy:

Nuclear Energy is a reaction in which the nucleus of an atom undergoes a change to form a new atom and releases an enormous amount of energy. 

There are two distinct ways of obtaining nuclear energy.

(a) Nuclear fission 

(b) Nuclear fusion. 

It is used for heat generation and fuel for marine vessels.


  • The alternative source of energy due to the depletion of fossil fuels.
  • A large amount of energy is released from a small amount of fuel.


  • Risk of nuclear waste leakage.
  • High cost of setting up the nuclear plant.
  • Pollution of the environment.

Due to the shortage of traditional energy sources of fossil fuels, the usage of solar energy and other renewable forms of energy is on the rise. Refer to our NCERT Solutions for Class 10 Science Chapter 14 to understand how energy sources are evolving in recent years.

Environmental Consequences

The environmental consequences due to the growing energy demand are:

  • Acid rain is produced due to the combustion of fossil fuels which damages the plants (crops), soil, and aquatic life.
  • Increase in greenhouse gas and carbon dioxide in the atmosphere.
  • The building of hydropower plants is a disturbing ecological balance.
  • Nuclear power plants are the primary cause of increased radioactivity in the environment.

NCERT Solutions for Class 10 Science Chapter 14: Exercises &  Solutions

Class 10 Science NCERT Solutions Chapter 14 provided by Extramarks is the most reliable source for students to refer to and practice the questions expected from this chapter. All the questions are solved with step-by-step answers to understand the concepts better. Questions from the textbooks are also answered here. Students will get access to a repository of exam-specific questions, such as MCQs, short and long-answer questions, and more.

NCERT Solutions – Short-answer Questions

NCERT Solutions – MCQ’s

NCERT Solutions – Long-answer Questions

Furthermore, in addition to NCERT Solutions for Class 10 Science Chapter 14, students may access NCERT Solutions for all other chapters:

Chapter 1 Chemical Reactions and Equations
Chapter 2 Acids, Bases and Salts
Chapter 3 Metals and Non-metals
Chapter 4 Carbon and Its Compounds
Chapter 5 Periodic Classification of Elements
Chapter 6 Life Processes
Chapter 7 Control and Coordination
Chapter 8 How do Organisms Reproduce?
Chapter 9 Heredity and Evolution
Chapter 10 Light Reflection and Refraction
Chapter 11 Human Eye and Colourful World
Chapter 12 Electricity
Chapter 13 Magnetic Effects of Electric Current
Chapter 14 Sources of Energy
Chapter 15 Our Environment
Chapter 16

NCERT Exemplar Class 10 Science

NCERT Exemplar Class 10 Science is one of the most definitive study and practice-oriented materials developed by subject matter experts.. Students need to get acquainted with all types of questions to master the topic and continue the process of learning with excellent academic results. By practicing these advanced levels of questions through the Exemplar, students not only get a good knowledge of all the concepts of this chapter, analyze their shortcomings and overcome them before facing the board examinations but also can prepare well for the competitive examination such as Olympiads, JEE, NEET, etc.

Furthermore, students can refer to the Exemplar problem and solutions for Class 10 Science chapter-wise on the Extramarks’ website.

NCERT Solutions Class 10 Science -Exemplar Questions and Answers

Key Features of NCERT Solutions for Class 10 Science Chapter 14- Sources of Energy

Extramarks has helped lakhs of students with their studies and exam preparation. Our NCERT solutions and other study materials are prepared by subject matter experts with years of experience.

 Following are some of the advantages of  studying from our NCERT Solutions:

  • Our NCERT Solutions provides detailed solutions to the chapter questions that help you fetch more marks in the examinations by providing authentic and reliable study material.
  • The content of our NCERT Solutions is created based on the latest NCERT textbooks and  CBSE guidelines.   
  • The chapter notes and answers are prepared by highly qualified and experienced science faculty.
  • NCERT Solutions for Class 10 Science Chapter 14 provides well-explained solutions to all the in-text and end-text questions in the chapter.   It also covers tricky and difficult questions to test their understanding of the concept and apply those concepts learned in real-life situations.

Students can score good marks in their school exams, assignments, and final board exams by referring to Class 10 Science Chapter 14 NCERT Solutions and other study resources from the Extramarks’ website. We do have a repository of educational material designed to answer all your queries. Extramarks is a one-stop solution to all your problems. 

Q.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.


The correct option is (b).
Explanation: A solar water heater requires bright and intense sunlight to function. Due to absence of sunlight on a cloudy day, solar energy is not available for the solar heater to work properly.

Q.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


The correct option is (c).

Explanation: Bio-mass Energy Source: The energy source which can be obtained from plants materials and animal wastes are called bio-mass energy source.
Wood is a plant material, gobar gas is formed from animal dung and coal is a fossil fuel obtained from the buried remains of plants and animals. Therefore, these are bio mass products.
Nuclear energy is released during nuclear fission and fusion and produces tremendous amount of energy. Hence, nuclear energy is not an example of bio-mass energy source.

Q.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


The correct option is (c).
Explanation: Nuclear energy is produced during nuclear fission and fusion. In nuclear fission, the nucleus of heavy atoms (such as uranium, plutonium) is bombarded with low-energy neutrons. Therefore, uranium atom breaks into two lighter nuclei. This reaction produces huge amount of energy. In nuclear fusion, two lighter nuclei are fused together to form a relatively heavier nuclei. This reaction produces tremendous amount of energy. These reactions can be carried out in the absence or presence of sunlight.

Q.4 Compare and contrast fossil fuels and the Sun as direct sources of energy.


Fossil Fuels: The fuels such as coal, petroleum, natural gas etc. are the energy sources those are found under the Earth’s crust. Nowadays, these energy sources are being used in a large scale. These energy sources are limited in the nature. These are non-renewable sources of energy and require millions of years for their formation.

Solar Energy: It is a renewable and direct source of energy produced by the Sun. The Sun has been shining from several years. Solar energy is free of cost to all in a huge amount.

Q.5 Compare and contrast bio-mass and hydro electricity as sources of energy.


Bio-mass is a renewable source of energy which is obtained from dead plants and animal wastes. It is the result of natural process. Therefore, it can be naturally refilled.

Examples: Gobar-gas, wood, etc.

Hydro-electricity is also a renewable source of energy. It is obtained from the potential energy stored in water at a height.

Example: Electricity generated at dams.

Q.6 What are the limitations of extracting energy from-

(a) the wind?
(b) waves?
(c) tides?


(a) Wind mills are used to harness wind energy. A windmill cannot generate electricity if the speed of wind is less than 15 km/h. Moreover, a large number of windmills are required, which covers a large area.

(b) To extract energy from waves, very strong ocean waves are required.

(c) It requires high tides to extract energy from tides. Moreover, the occurrence of tides depends on the relative positions of Sun, Moon, and Earth.

Q.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?


(a) The source of energy that cannot be exhausted in nature is called renewable source of energy.
Examples: Sun, wind, moving water, bio-mass, etc.

The source of energy that can be exhausted in nature is called non-renewable source of energy.
Examples: Coal, petroleum, natural gas, etc.

(b) Exhaustible sources are those sources of energy, which will deplete after a few hundred years later.
Examples: Coal, petroleum, etc.

Inexhaustible resources of energy are those sources which will not deplete in future.
Example: Bio-mass.

Yes. The options given in (a) and (b) are same.

Q.8 What are the qualities of an ideal source of energy?


A source of energy which is considered as an ideal source of energy must be economical, easily accessible, pollution free, easy to store and transport and able to produce huge amount of heat and energy on burning.

Q.9 What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?


Advantages: Solar cooker requires energy of Sun to operate. Solar energy is inexhaustible renewable source of energy and free for all and available in nature in huge amount.

Disadvantages: Solar cookers are very expensive. They do not work in absence of sunlight. Therefore, on a cloudy day, it becomes useless.

The regions where days are very short or places with cloud covers round the year, have limited utility for solar cooker.

Q.10 What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption?


There is a huge demand of fossil fuels due to industrialisation in all over the world. Burning of fossil fuels releases many harmful gases in the atmosphere and increases the level of green house gas content in the atmosphere. It has increased the problem of global warming.

The consumption of fossil fuels cannot be completely reduced. However, some measures can be taken such as using electrical appliances wisely and not wasting electricity. In place of using our own vehicles, public transport system with mass transit must be adopted on a large scale.

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