NCERT Solutions for Class 10 Science Chapter 14 Sources of Energy


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.

Benefits of NCERT Solutions

NCERT Solutions for Class 10 contain immensely significant points and for every chapter, each concept is simplified so that it turns out to be easy to remember that expands the odds of scoring commendably in the board exams. NCERT Solutions for class 10 by Extramarks is the best reference material for test preparation. Given below are a couple of points about how these solutions help in exam preparation.
1. It helps students practice loads of questions from every chapter which encourages them to make their concepts more grounded..

2. NCERT Solutions for Class 10 encourages you to upgrade your knowledge and clear your concepts with the goal that you can score well in your exams.

3. These solutions are the best examination materials to know your weak and strong points. It is essential to work on your weak points to score well in the exams. 

4. Most of the questions in exams are asked in a similar arrangement from NCERT textbooks. Hence, students should altogether revise every chapter’s solution to get a good command in subjects

Tips & Strategies for Class 10 Exam Preparation

1. Make a timetable to complete your syllabus and make time for revision.

2. Refer to NCERT Solutions given on the Extramarks website to clear your concepts anytime while preparing for your exams.

3. Start studying with the help of Extramarks – The Learning App to pass your exams with flying colours. It provides complete study material with solved and unsolved papers.

4. It is important to clear all your doubts before the exam with your teachers or Alex (an AI studybot).

5. While reading or learning a chapter, make sure to make notes with algorithms, formulas, theorems, etc., and study them for a quick revision before exams.

6. Practice an ample number of question papers to make your concepts stronger.

7. Take rest and a proper meal. Don’t stress too much.

Why opt for Extramarks NCERT Solutions for Class 10 ?

Extramarks provide NCERT Solutions for all subjects at your fingertips. These solutions are designed by subject matter experts and provide solutions to every NCERT textbook questions. Extramarks especially focuses on making learning interactive, effective and for all classes. We provide free NCERT Solutions for class 10 and all other classes

Frequently Asked Questions

How to use NCERT Solutions for scoring in class 10 Maths CBSE Board Exams?

NCERT 10 solutions for math are in-depth solutions written in very basic and simple language which makes them easy to understand. It gives sufficient study material to practice with to the students which the latter can use for practicing for board exams. Extramarks website has NCERT solutions for all classes that can be used by students of different classes. These solutions can be accessed by visiting the footer section of the website. Prepare notes and learn from NCERT solutions, go through them thoroughly before the exam, and practice with the questions that crop up in NCERT solutions.

Do you provide solutions for All subjects for class 10 CBSE?

Yes, Extramarks website has NCERT solutions for class 10 along with all other classes of CBSE listed on the footer section. These solutions have been prepared by top faculty members who have years of experience and expertise in teaching CBSE students.

Why are the NCERT solutions Important for Class 10?

 Extramarks class 10 NCERT solutions are crucial for board preparation for students. These solutions are given in a simple language which makes it easy to understand for all and it proves to be the basis for board examination which further helps the students in understanding the extensive study material. Class 10 NCERT solutions focus on fundamental clarity of the concepts which further helping in clearing all doubts and helping students achieve concept clarity. NCERT solutions provide enough practice and study material to students that they can use to test their knowledge

Will NCERT solutions of Class 10th be good enough to prepare for the Class 10 Board exams?

Yes, class 10 solutions (NCERT) are sufficient to prepare for class 10 board exams. NCERT solutions are simple and easy to understand written in a way that is appealing to students. NCERT solutions form the basis of examination of class 10 board so they prove to be a sufficient solution which also gives enough study material to practice with to students. Different types of NCERT solutions help students prepare for the exam through varied formats and provide them concept clarity.

Do I need to use textbook solutions other than NCERT solutions for Class 10 exam prep

Class 10 CBSE NCERT solutions are sufficient to prepare for board exams but if you want to test your knowledge and would like to browse more solutions then you can use textbook solutions to prepare for the exam. Although the NCERT solutions are enough for preparing for the exam, you can check out the solved and unsolved sample papers along with textbook solutions from Extramarks - The Learning App and website

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