CBSE Class 10 Science NCERT Solutions: Chapter 14 Source of Energy

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NCERT Solutions PDF Class 10 PDF

This chapter delves into the fundamental concepts of energy sources, crucial for Class 10 Science students following the CBSE curriculum. The NCERT Solutions for Chapter 14, 'Source of Energy,' provide clear explanations and answers to key questions. Students will explore the differences between renewable and non-renewable energy sources, understand the environmental implications of using various fuels like fossil fuels and biomass, and learn about the conversion of energy from one form to another, such as in hydropower plants. The solutions also touch upon the causes of acid rain and identify the ultimate source of energy for life on Earth. These detailed solutions are designed to aid students in grasping complex topics, reinforcing their understanding, and preparing effectively for their board examinations by offering step-by-step guidance and accurate information.

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Quick info

BoardCBSE
ClassClass 10
SubjectScience (Exemplar)
Session2026
LanguageEnglish
TypeNCERT Solutions
Chapter14. Source of Energy

Chapter summary

Chapter 14, 'Source of Energy,' focuses on classifying energy sources into renewable and non-renewable categories. It examines the environmental impact of different energy sources, including fossil fuels, nuclear energy, and solar energy. The chapter also explains the working principles of energy conversion in systems like thermal and hydro power plants and identifies the sun as the ultimate source of energy. These NCERT Solutions offer detailed explanations for multiple-choice questions, clarifying concepts related to energy generation and its environmental consequences.

Learning outcomes

  • Differentiate between renewable and non-renewable sources of energy.
  • Identify the primary causes and consequences of acid rain.
  • Understand the process of energy conversion in hydropower plants.
  • Recognize the sun as the ultimate source of energy for Earth.
  • Evaluate the environmental impact of various energy sources.

Topics covered

Paper topics

  • Renewable Energy Sources
  • Non-renewable Energy Sources
  • Fossil Fuels
  • Solar Energy
  • Hydroelectric Power
  • Thermal Power Plants
  • Nuclear Energy
  • Geothermal Energy
  • Acid Rain
  • Ultimate Source of Energy
  • Energy Conversion
  • Environmental Pollution from Energy

Important topics

  • Classification of Energy Sources (Renewable vs. Non-renewable)
  • Environmental Impact of Energy Sources
  • Energy Conversion in Power Plants
  • The Sun as the Ultimate Energy Source
  • Causes and Effects of Acid Rain

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Questions and Solutions

Multiple Choice Questions - 1

1. Which of the following is a non-renewable source of energy?

Wood Sun Fossil fuels

Wind

Solution: The correct answer is (c) Fossil fuels. Fossil fuels, such as coal, petroleum, and natural gas, are finite resources that were formed over millions of years from the remains of dead organisms. They are consumed much faster than they can be naturally replenished, classifying them as non-renewable energy sources. Wood and wind are considered renewable, and the sun is a virtually inexhaustible source of energy.

Multiple Choice Questions - 2

2. Acid rain happens because

sun leads to heating of upper layer of atmosphere

burning of fossil fuels release oxides of carbon, nitrogen and sulphur in the atmosphere

electrical charges are produced due to friction amongst clouds

earth atmosphere contains acids

Solution: The correct answer is (b) burning of fossil fuels release oxides of carbon, nitrogen and sulphur in the atmosphere. When fossil fuels like coal and oil are burned in power plants and vehicles, they release pollutants such as sulfur dioxide (SO_2) and nitrogen oxides (NO_x) into the atmosphere. These gases react with water, oxygen, and other chemicals in the atmosphere to form sulfuric acid and nitric acid, which then fall to the Earth as acid rain.

Multiple Choice Questions - 3

3. Fuel used in thermal power plants is

water

uranium

biomass

fossil fuels

Solution: The correct answer is (d) fossil fuels. Thermal power plants primarily generate electricity by burning fossil fuels, most commonly coal. The heat produced from burning these fuels is used to convert water into steam, which then drives turbines connected to generators. While natural gas and petroleum are also used, coal remains the dominant fuel in many thermal power plants worldwide.

Multiple Choice Questions - 4

4. In a hydro power plant

Potential energy possessed by stored water is converted into electricity

Kinetic energy possessed by stored water is converted into potential energy

Electricity is extracted from water

Water is converted into steam to produce electricity

Solution: The correct answer is (a) Potential energy possessed by stored water is converted into electricity. In a hydroelectric power plant, water is stored at a height in a dam, giving it potential energy. When this water is released, its potential energy is converted into kinetic energy as it flows downwards. This moving water turns the blades of a turbine, which is connected to a generator that produces electricity.

Multiple Choice Questions - 5

5. Which is the ultimate source of energy?

Water Sun Uranium

Fossil fuels

Solution: The correct answer is (b) Sun. The sun is considered the ultimate source of energy for almost all life on Earth. Plants convert solar energy into chemical energy through photosynthesis. Fossil fuels are derived from ancient plants and animals, storing energy originally captured from the sun. Even wind and wave energy are ultimately driven by solar energy.

Multiple Choice Questions - 6

6. Which one of the following forms of energy leads to least environmental pollution in the process of its harnessing and utilisation?

Nuclear energy

Thermal energy

Solar energy

Geothermal energy

Solution: The correct answer is (c) Solar energy. Solar energy is a clean and renewable source that produces minimal pollution during operation. Nuclear energy involves radioactive materials and waste disposal challenges. Thermal energy, often derived from burning fossil fuels, releases greenhouse gases and other pollutants. Geothermal energy can sometimes release underground gases and requires careful management.

Common mistakes

  • Confusing renewable and non-renewable energy sources.
  • Misunderstanding the process of energy conversion in power plants.
  • Incorrectly identifying the ultimate source of energy.
  • Overlooking the environmental impact of different energy sources.

Revision tips

  • Create a table to compare and contrast renewable and non-renewable energy sources.
  • Draw diagrams to illustrate the energy conversion process in a hydropower plant.
  • Focus on understanding the link between burning fossil fuels and environmental issues like acid rain.
  • Review the explanations for each question to reinforce key concepts.

Practice MCQs

Q1. Which of the following is classified as a non-renewable source of energy?

Q2. Acid rain is primarily caused by:

Q3. What is the primary fuel used in most thermal power plants for generating electricity?

Q4. In a hydroelectric power plant, the energy conversion process involves:

Q5. What is considered the ultimate source of energy for most energy forms on Earth?

Q6. Which form of energy generation results in the least environmental pollution during its harnessing and utilization?

Frequently asked questions

What is the main difference between renewable and non-renewable energy sources?

Renewable energy sources can be replenished naturally over a short period, like solar and wind energy. Non-renewable sources exist in finite quantities and are consumed much faster than they can be formed, such as fossil fuels.

Why is the sun considered the ultimate source of energy?

The sun is the ultimate source because it provides energy directly for processes like photosynthesis and indirectly for fossil fuels, which are formed from ancient organic matter that originally captured solar energy.

How does burning fossil fuels lead to acid rain?

Burning fossil fuels releases oxides of sulfur and nitrogen into the atmosphere. These gases react with water, oxygen, and other chemicals to form sulfuric and nitric acids, which then fall to the Earth as acid rain.

What type of energy conversion happens in a hydroelectric power plant?

In a hydroelectric power plant, the potential energy stored in water at a height is converted into kinetic energy as it flows down, which then turns turbines to generate electricity.

Which energy source causes the least environmental pollution?

Solar energy is generally considered to cause the least environmental pollution during its harnessing and utilization compared to fossil fuels, nuclear energy, or geothermal energy.

What is the primary fuel used in thermal power plants?

Thermal power plants primarily use fossil fuels, such as coal, natural gas, and petroleum, to generate heat for producing steam that drives turbines.

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