Bihar Board Class 10 · Science · Matric exam 2027
Chapter 14: Sources of Energy
This chapter’s questions from Bihar Board (BSEB)’s real papers of 2021–2026 — the 20 asked most often, 3 with the full model answer, 17 with how the answer begins — and objective questions with the board’s key. All 22 questions of this chapter, with answers, are in the app.
- marks a year (about)
- 4
- questions a year (about)
- 5
- rank in Science
- #10
From 6 years of papers, 2021–2026 · full chapter-wise marks
VVI questions — the ones the board asked most (20)
- Q1Short answer2 marksAsked: 2021, 2025
What is nuclear fusion?
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Model answer · nuclear fusion
- 1.Nuclear fusion is the process in which two light nuclei combine to form a heavier nucleus. Fusion means joining lighter nuclei to make a heavier nucleus, most commonly hydrogen or hydrogen isotopes to create helium, such as 2H + 2H → 3He (+ n).1 mark
- 2.A large amount of energy is released in this process, as the mass of the product is little less than the sum of the masses of the original individual nuclei. Such nuclear fusion reactions are the source of energy in the Sun and other stars.1 mark
- Write the words 'two light nuclei combine to form a heavier nucleus' in the first paragraph.
- Give the example equation 2H + 2H → 3He (+ n) to support the definition.
- Mention that a large amount of energy is released, linking it to the Sun and other stars.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
- Q2Short answer2 marksAsked: 2022, 2023
What are the drawbacks of fossil fuels ?
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Model answer · drawbacks of fossil fuels
- 1.Burning of fossil fuels causes air pollution because the oxides of carbon, nitrogen and sulphur that are released on burning fossil fuels are acidic oxides. These lead to acid rain which affects our water and soil resources.1 mark
- 2.The carbon dioxide gas produced on burning fossil fuels causes the green-house effect of gases, which leads to global warming.1 mark
- Write 'acid rain' and 'oxides of carbon, nitrogen and sulphur' as the cause of air pollution.
- Mention 'green-house effect' and 'global warming' together for the second point.
- Keep both points separate; do not mix acid rain with global warming in one sentence.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
- Q3Long answer6 marksAsked: 2025
Describe the structure and working method of a biogas plant.
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Model answer · structure and working of biogas plant
- 1.A biogas plant has a dome-like structure built with bricks. A slurry of cow-dung and water is made in the mixing tank from where it is fed into the digester.1 mark
- 2.The slurry is sent to the digester, which is a sealed chamber in which there is no oxygen. Anaerobic micro-organisms that do not require oxygen decompose or break down the complex compounds present in the cow-dung slurry. It takes a few days for this decomposition process to be complete.1.5 marks
- 3.As a result of the decomposition process, gases like methane, carbon dioxide, hydrogen and hydrogen sulphide are produced. This mixture of gases is called bio-gas, and since the starting material is mainly cow-dung, it is popularly known as 'gobar-gas'. Bio-gas is an excellent fuel as it contains up to 75% methane, burns without smoke, leaves no residue like ash, and has a high heating capacity.1.5 marks
- 4.The bio-gas produced is stored in the gas tank above the digester, from where it is drawn through the outlet pipe built on top of the dome for use. Bio-gas is used as fuel for cooking and is also used for lighting.1 mark
- 5.The slurry left behind after the gas is removed is taken out periodically and used as excellent manure, rich in nitrogen and phosphorous.1 mark
Diagram: Draw a dome-shaped brick structure labelled: Mixing tank, Slurry (cow-dung + water), Inlet chamber, Digester (sealed, anaerobic), Gas tank/dome, Outlet pipe (bio-gas to use), and Outlet for slurry/manure.
- Mention that the digester is 'a sealed chamber in which there is no oxygen' to earn the anaerobic point.
- List all four gases - methane, carbon dioxide, hydrogen and hydrogen sulphide - produced during decomposition.
- State that the leftover slurry is used as manure 'rich in nitrogen and phosphorous'.
Marks split from a structure derived from past papers (checked twice); not Bihar Board’s official scheme
- Q4Long answer6 marksAsked: 2026
What is energy crisis ? Mention its solution.
How the model answer begins
1. Energy crisis refers to the imbalance between demand and supply of energy, arising from the rapid depletion of conventional energy sources like coal, petroleum and natural gas due to population growth and…
The full answer from Medha Ma’am → - Q5Long answer6 marksAsked: 2025
Describe the structure and working method of a biogas plant.
How the model answer begins
1. A biogas plant is a dome-like structure built with bricks and concrete.
The full answer from Medha Ma’am → - Q6Long answer5 marksAsked: 2025
What is energy crisis ? Mention the measures to resolve it.
How the model answer begins
1. Energy crisis is the condition created due to the imbalance between the demand for energy and its supply. Our energy requirements increase with our standard of living and with technological progress, our demand for…
The full answer from Medha Ma’am → - Q7Long answer5 marksAsked: 2025
What is energy crisis ? Mention the measures to resolve it.
How the model answer begins
1. The imbalance between the demand for energy and its supply is called an energy crisis. With technological progress, our demand for energy increases day by day as our life-styles are changing and our basic requirements…
The full answer from Medha Ma’am → - Q8Short answer2 marksAsked: 2025
What is called the best source of energy?
How the model answer begins
1. A good source of energy is one which would do a large amount of work per unit volume or mass, that is, it has a high calorific value.
The full answer from Medha Ma’am → - Q9Short answer2 marksAsked: 2025
What are fossil fuels ?
How the model answer begins
1. Fossil fuels are fuels formed from the remains of plants and animals buried deep inside the earth for millions of years. These fuels were formed over millions of years ago and there are only limited reserves, so fossil…
The full answer from Medha Ma’am → - Q10Short answer2 marksAsked: 2025
What is fossil fuel? Write with example.
How the model answer begins
1. Fuels formed from the remains of ancient plants and animals over millions of years are called fossil fuels.
The full answer from Medha Ma’am → - Q11Short answer2 marksAsked: 2025
What are renewable and non-renewable sources?
How the model answer begins
1. Renewable sources of energy are such energy sources that can be regenerated. If we manage bio-mass by replacing the trees we cut down for fire-wood, we can be assured of a constant supply of energy at a particular rate.…
The full answer from Medha Ma’am → - Q12Short answer2 marksAsked: 2025
What are the benefits of a dam?
How the model answer begins
1. The benefits of a dam are that high-rise dams are constructed on the river to obstruct the flow of water and thereby collect water in larger reservoirs. This stored water ensures a continuous supply of water for…
The full answer from Medha Ma’am → - Q13Short answer2 marksAsked: 2026
What is geothermal energy ?
How the model answer begins
1. The heat energy generated from the hot rocks or magma located deep inside the earth is called geothermal energy. Due to geological changes, molten rocks formed in the deeper hot regions of earth's crust are pushed…
The full answer from Medha Ma’am → - Q14Short answer2 marksAsked: 2023
What do you mean by nuclear energy ?
How the model answer begins
1. Nuclear energy is the energy obtained from the process of fission or fusion of the atomic nucleus. In nuclear fission, the nucleus of a heavy atom such as uranium, plutonium or thorium is split apart into lighter nuclei…
The full answer from Medha Ma’am → - Q15Short answer2 marksAsked: 2023
What are the benefits of generating electricity from solar cell ?
How the model answer begins
1. Generating electricity from solar cells is pollution-free. Solar cells convert solar energy into electricity directly and do not cause any pollution, unlike devices that burn fossil fuels, making them…
The full answer from Medha Ma’am → - Q16Short answer2 marksAsked: 2022
What are the advantages of obtaining energy from wind?
How the model answer begins
1. Wind energy is a renewable source of energy that never gets exhausted. It is an environment-friendly and efficient source of renewable energy and requires no recurring expenses for the production of electricity.
The full answer from Medha Ma’am → - Q17Short answer2 marksAsked: 2022
Write the characteristics of solar energy.
How the model answer begins
1. Solar energy is a renewable and inexhaustible source of energy. The Sun has been radiating an enormous amount of energy at the present rate for nearly 5 billion years and will continue radiating at that rate for about 5…
The full answer from Medha Ma’am → - Q18Short answer2 marksAsked: 2022
What is nuclear fission?
How the model answer begins
1. Nuclear fission is the process in which the nucleus of a heavy atom, such as uranium, plutonium or thorium, is split apart into lighter nuclei.
The full answer from Medha Ma’am → - Q19Short answer2 marksAsked: 2022
Is fossil fuel renewable? Give reasons.
How the model answer begins
1. Fossil fuel is not a renewable source of energy. The fossil fuels are non-renewable sources of energy.
The full answer from Medha Ma’am → - Q20Short answer2 marksAsked: 2025
What is called the best source of energy ?
How the model answer begins
1. A good source of energy would be one which would do a large amount of work per unit volume or mass.
The full answer from Medha Ma’am →
2 more questions of this chapter, each with its model answer, in the AskMedha app.
Objective questions with the board’s key (10)
- 1. Bihar Board 2026
Which of the following is used in electricity production ?
- (A) Iron
- (B) Copper
- (C) Wind ✓
- (D) Soil
Answer: (C)
- 2. Bihar Board 2026
Coal and Petroleum are
- (A) fossil fuels ✓
- (B) renewable fuels
- (C) nuclear fuels
- (D) all of these
Answer: (A)
- 3. Bihar Board 2026
Which of the following is an example of 'ground water'?
- (A) River
- (B) Well ✓
- (C) Pond
- (D) Sea
Answer: (B)
- 4. Bihar Board 2026
An example of fossil fuel is
- (A) Petroleum products
- (B) Coal
- (C) Both (A) and (B) ✓
- (D) None of these
Answer: (C)
- 5. Bihar Board 2026
Which of the following is the main source of energy on earth ?
- (A) Coal
- (B) Water
- (C) Air
- (D) Sunlight ✓
Answer: (D)
- 6. Bihar Board 2026
Which is used in solar cells ?
- (A) Uranium
- (B) Plutonium
- (C) Silicon ✓
- (D) None of these
Answer: (C)
- 7. Bihar Board 2025
What type of energy source is hydroelectric energy?
- (A) Renewable ✓
- (B) Non-renewable
- (C) Both (A) and (B)
- (D) None of these
Answer: (A)
- 8. Bihar Board 2025
In which state is the Kalpakkam Nuclear Power Plant located ?
- (A) Karnataka
- (B) Tamil Nadu ✓
- (C) Uttar Pradesh
- (D) Gujarat
Answer: (B)
- 9. Bihar Board 2025
The two non-renewable sources of energy are
- (A) Gobar gas and biomass
- (B) Coal and petroleum ✓
- (C) Biomass and petroleum
- (D) None of these
Answer: (B)
- 10. Bihar Board 2025
Which of the following is a renewable resource?
- (A) Coal
- (B) Forest ✓
- (C) Petroleum
- (D) None of these
Answer: (B)
Questions parents and students ask
- How many marks does "Sources of Energy" carry in Bihar Board Class 10 Science?
- In the Bihar Board papers of 2021–2026, this chapter carried about 4 marks and about 5 questions a year; by marks it ranks 10 in Science.
- Which are the most important (VVI) questions of "Sources of Energy"?
- The 20 questions above are from the board’s real papers, each with the years it was asked; the most-asked come first with their full model answers. All 22 written questions of this chapter, with answers, are in the AskMedha app.
- Do the answers follow the board’s marking scheme?
- BSEB does not publish a marking scheme. Each answer is written point by point on a structure derived from past papers and checked by a second, independent model; it is never called the board’s official scheme.
The same preparation, with Medha Ma’am — on your phone
Every question of every chapter with its model answer, practice questions in the board’s own shapes, 60 minutes of class a day, written answers marked, a test every Sunday and a WhatsApp report to parents.
Medha Ma’am is an AI teacher, not a live tutor. Every answer is checked twice; a person takes responsibility.