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Lakhmir Singh Solutions for Class 10 Physics Chapter 3 Sources of Energy
By Ankit Gupta
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Updated on 11 Jun 2025, 16:04 IST
Class 10 is one of the most important years in a student’s school life. Physics, as a subject, plays a major role in developing scientific thinking and practical knowledge. One of the most interesting and important chapters in Class 10 Physics is “Sources of Energy.” It helps students understand where we get our energy from and how we use it in our daily lives.
To make this chapter easier and more understandable, many students refer to Lakhmir Singh Solutions. These solutions offer clear explanations, simple answers, and step-by-step problem-solving methods that help students prepare better for exams.
The “Sources of Energy” chapter explains different kinds of energy sources—like fossil fuels, solar energy, wind energy, hydroelectricity, and biomass. It also teaches the difference between renewable and non-renewable sources. Students learn how energy is produced, stored, and used, and how it affects the environment. This chapter is not just about learning for exams; it also makes students aware of the importance of using clean and sustainable energy in the future.
Lakhmir Singh Solutions are very helpful because they are written in easy-to-understand language. They follow the NCERT pattern and cover all textbook questions. The answers are well-structured, so students can easily learn and revise the concepts. These solutions also include extra questions and tips that help students gain confidence and improve their problem-solving skills. Whether it's a theoretical question or a numerical one, the solutions guide the student in a step-by-step way, which makes learning stress-free and enjoyable.
Another big advantage of using Lakhmir Singh Solutions is that they help students understand the logic behind every concept. Instead of memorizing facts, students learn why something happens and how it works. This deeper understanding helps in building a strong base for higher studies in science. It also improves critical thinking and scientific reasoning, which are essential in real life.
In conclusion, Lakhmir Singh Solutions for Class 10 Physics “Sources of Energy” is a great study tool. It supports students in scoring well, gaining clarity on concepts, and becoming more environmentally aware. By using these solutions, students can make learning Physics simple, interesting, and effective.
Download Lakhmir Singh Solutions for Class 10 Physics Chapter 3 Sources of Energy PDF Here
Lakhmir Singh Class 10 Chapter 3 PDF includes detailed solutions, examples, and extra questions to help you master real numbers and other topics. Click here to download the Lakhmir Singh Class 10 Chapter 3 PDF.
Access Answers to Lakhmir Singh Solutions for Class 10 Physics Chapter 3 Sources of Energy Electricity
Q1. Name a non-renewable source of energy other than fossil fuels.
Answer: Nuclear fuels like uranium are non-renewable sources of energy apart from fossil fuels.
Q2. What is the calorific value of a fuel?
Answer: Calorific value is the amount of heat released when 1 gram of fuel is burned completely.
Q3. What does it mean if the calorific value of cooking gas is 50kJ/g?
Answer: It means that burning 1 gram of cooking gas will produce 50 kilojoules of heat energy.
Q4. Which produces more heat per gram when burned: coal or LPG?
Answer: LPG gives more heat per gram than coal because its calorific value is higher.
Q5. What is the ignition temperature of a fuel?
Answer: Ignition temperature is the minimum temperature at which a fuel catches fire and starts burning.
Q6. What does it mean if the ignition temperature of a fuel is 80°C?
Answer: It means that the fuel needs to be heated to at least 80°C before it can catch fire.
Q7. Fill in the blank: The amount of heat produced by burning a unit mass of a fuel completely is known as its ______ value.
Answer: Calorific value.
Do Check: Lakhmir Singh Solutions for Class 10
Q8. What is a source of energy? Name the two main types of energy sources.
Answer: A source of energy is something that provides energy for use. The two main types are:
a) Renewable sources
b) Non-renewable sources.
Q9. List four features of a good source of energy.
Answer:
a) Easy to store and transport
b) Safe and simple to use
c) Easily available
d) Gives a lot of energy per unit mass.
Q10. What is a non-renewable source of energy? Give two examples.
Answer: A non-renewable source is one that can run out with use. Examples are coal and petroleum.
Q11. What is a renewable source of energy? Give two examples.
Answer: A renewable source is available in large amounts and does not run out. Examples are solar energy and wind energy.
Q12. What is the difference between renewable and non-renewable sources of energy? Give examples.
Answer: Renewable sources are unlimited like sunlight and wind. Non-renewable sources are limited and can be used up, like coal and petroleum.
Q13. Why are fossil fuels called non-renewable?
Answer: Fossil fuels are non-renewable because once they are used up, they cannot be replaced quickly.
Q14. Name two renewable sources of energy and explain why they are renewable.
Answer: Wind and water are renewable because they are available in nature all the time and can be used again and again.
Q15. Name two non-renewable sources of energy and explain why they are non-renewable.
Answer: Coal and petroleum are non-renewable because they take millions of years to form and cannot be replaced quickly.
Q16. a) Classify the following into renewable and non-renewable sources: Coal, wind, tides, petroleum, wood, natural gas.
Answer: Renewable: wind, tides, wood; Non-renewable: coal, petroleum, natural gas.
b) What is the basis of this classification?
Answer: The classification is based on whether the energy source can be replaced or not.
Q17. Coal is made from wood, so why is coal non-renewable while wood is renewable?
Answer: Coal takes millions of years to form, but wood grows much faster. So coal can run out, but wood can be replaced quickly.
Q18. a) What is a fuel? Give five examples.
Answer: A fuel is a material that gives heat when burned. Examples: wood, coal, diesel, LPG, kerosene.
b) What are the qualities of a good fuel?
Answer: i) High energy output
ii) Proper ignition temperature
iii) Easily available and cheap
iv) Does not give harmful gases when burned.
c) Fuel A: Calorific value = 55kJ/g, Ignition temp = 80°C, gases = CO2 and H2O. Fuel B: Calorific value = 80kJ/g, Ignition temp = 10°C, gases = CO2, CO, SO2. Compare the fuels.
Answer: Fuel A:
i) Lower heat output (disadvantage)
ii) Safe ignition temp (advantage)
iii) No harmful gases (advantage).
Fuel B:
i) High heat output (advantage)
ii) Low ignition temp (can be risky)
iii) Releases harmful gases (disadvantage).
Q19. Which of these is a renewable source of energy?
a) petrol
b) natural gas
c) biogas
d) kerosene
Answer: c) biogas
Q20. Which of the following is a non-renewable source of energy?
a) wood
b) alcohol
c) hydrogen gas
d) natural gas
Answer: d) natural gas
FAQs on Lakhmir Singh Solutions for Class 10 Physics Sources of Energy
What is covered in Chapter 3 – Sources of Energy in Lakhmir Singh’s Class 10 Physics book?
Chapter 3 explains different sources of energy like fossil fuels, solar energy, wind energy, hydro power, geothermal, and biomass. It also discusses the advantages and disadvantages of each source, and the importance of using renewable energy for a sustainable future.
How are Lakhmir Singh Solutions helpful for Chapter 3: Sources of Energy?
The solutions provide clear, simple, and accurate answers to all textbook questions. They also include extra questions, solved examples, and diagrams that help students understand the concepts better and prepare effectively for exams.
Are Lakhmir Singh Solutions based on the latest CBSE syllabus?
Yes, the solutions strictly follow the CBSE Class 10 Physics syllabus and NCERT guidelines. They are regularly updated to reflect any changes in the curriculum.
Do the solutions include explanations for both theory and numericals?
Absolutely. The solutions explain both theoretical concepts and numerical problems step-by-step. This helps students grasp the reasoning behind each answer and improves their problem-solving skills.
Can Lakhmir Singh Solutions help in board exam preparation?
Yes. These solutions are highly useful for board exam preparation. They offer well-structured answers and cover all key topics that frequently appear in the CBSE Class 10 board exams.
Are diagrams and illustrations included in the solutions?
Yes, many solutions include labeled diagrams and illustrations, especially for topics like solar cooker, windmill, or biogas plant. These visual aids help in better understanding and also improve presentation in exams.
Where can I find the Lakhmir Singh Solutions for Class 10 Physics Chapter 3?
You can find the solutions online on trusted educational websites, in PDF format, or in guidebooks available in bookstores. Many school platforms also offer these solutions as part of their study material.