Chapter 12: SOURCES OF ENERGY

Chapter 12. Sources of Energy Class 10 Science and Technology (212) NIOS Textbook Solutions

Chapter 12. SOURCES OF ENERGY

INTEXT QUESTIONS 12.1

1. List out any five activities from your daily life in which different forms of energy are involved.

Answer: The five daily activities involving different forms of energy are:

(a) Cooking of food – heat energy and chemical energy of fuel

(b) Lightning of bulbs – electrical energy and light energy

(c) Talking to each other – sound energy

(d) Cycling – mechanical energy

(e) Torch – chemical energy of cells.

2. What are the three most common forms of energy that we use frequently?

Answer:  The three most common forms of energy that we use frequently are:

(i) Heat, (ii) Light and (iii) Electricity

3. Differentiate between renewable and non-renewable sources of energy.

Answer: The difference between renewable and non-renewable sources of energy are :

Renewable Sources of Energy	Non-Renewable Sources of Energy
1. These sources can be replenished or renewed naturally over a short period of time.	1. These sources exist in limited quantities and take millions of years to form, so they get exhausted with use.
2. They are generally eco-friendly and cause little or no pollution (e.g., solar, wind, tidal energy).	2. They cause significant environmental pollution, including air, water, and soil pollution (e.g., coal, petroleum).
3. They are available abundantly in nature and are essentially free once the harnessing system is installed.	3. They are costly to extract, transport, and process, and their prices keep increasing due to scarcity.

INTEXT QUESTIONS 12.2

1. Name any four non-renewable sources of energy and give at least one advantage of each.

Answer:

 

Non-renewable Source of Energy	One Advantage
(i) Coal	It is cheaper and easily accessible.
(ii) Oil	It is excellent sources of energy for our transportation.
(iii) Natural Gas	It is cleaner burning than gasoline, but does produce Carbon Dioxide, the main greenhouse gas and it has high calorific value.
(iv) Nuclear Fuel	Nuclear fuel used in nuclear power stations does not burn and hence no waste gases are produced.

2. Nuclear energy is considered to be a very powerful alternative of fossil fuels. Even then why is it not being used on a much larger scale?

Answer: Nuclear energy is considered a very powerful alternative to fossil fuels. Even then, it is not being used on a much larger scale because of the following reasons:

(i) It is difficult to set up nuclear power plants.

(ii) A large amount of money is required to ensure safety in nuclear power plants.

(iii) The nuclear waste produced is hazardous and its disposal is difficult.

3. What are the limitations of using natural gas for meeting our energy requirements?

Answer: The limitations of using natural gas for meeting our energy requirements:

(i) Stock of natural gas is limited and it cannot be replenished.

(ii) Use of natural gas can cause unpleasant smell in the area.

INTEXT QUESTIONS 12.3

1. Name any one alternative source of energy which you would like to use in your home. Justify your answer. Solar energy. Because it is free and easily available in the area in which we live. It can be used for cooking, water heating and also for keeping our home warm in winter.

2. Biofuel is considered to be a good fuel. Why is it not being used on a mass scale to replace the fossil fuels in our country?

Answer: Biofuel is considered a good fuel, but it is not being used on a mass scale to replace fossil fuels in our country because of the following reasons:

(i) The bio-fuel is not as energy efficient as petrol.

(ii) The main ingredient of bio-fuel i.e. methane is harmful to the environment.

(iii) Bio-fuel is a relatively expensive source for generating energy, both in terms of producing the biomass and converting it to ethanol.

3. List any five traditional uses of solar energy.

Answer: The five traditional uses of solar energy are :

(i) drying of clothes (ii) heating of water (iii) drying crops,

(iv) breeding and raising chicks and (v) drying manure.

INTEXT QUESTIONS 12.4

1. What are the steps that you can and should take for saving energy at home or in the office?

Answer: The steps for saving energy are :

(i) Switch off lights, fans and other appliances when not in use.

(ii)Water taps should not be left open.

(iii) While cooking vegetables the vessel should remain covered.

 (iv) For cooking, only the required quantity of water should be used.

(v) Soak pulses in water for some time before cooking,

(vi) use of more efficient appliances.

(vii) use public transport in place of your own vehicle to save fuel.

(viii) Share automobiles rides to office, instead of driving alone to office

2. List at least three reasons behind the energy crisis in our country.

Answer: Reasons behind the energy crisis in our country are :

(i) Our over-dependence on limited and exhaustible sources of energy such as our coal and oil deposits.

(ii)Increasing gap in the demand and supply of the energy.

(iii) Ever increasing prices of the energy and fuel from other countries.

(iv) Reluctance in using alternative and renewable sources of energy, such as solar, wind, bio-energy, etc..

(v) Overuse and misuse of the available sources of energy.

3. What do you mean by the statement that ‘energy can neither be created nor destroyed?

Answer: The statement ‘energy can neither be created nor be destroyed’ means that energy the total energy remains constant. It can only be transformed from one form of energy into another.

TERMINAL EXERCISE

1. What are different forms of energy?

Answer: The different forms of energy are  heat energy, light energy, mechanical energy, electrical energy, chemical energy and sound energy .

2. Distinguish between conventional and non-conventional sources of energy.

Answer: The Difference between Conventional and Non-conventional Sources of Energy

Conventional Sources of Energy	Non-conventional Sources of Energy
These are traditional sources of energy used for a long time.	These are modern and alternative sources of energy.
They are mostly exhaustible and may get depleted.	They are generally renewable and can be used continuously.
They cause more environmental pollution.	They produce less or no pollution.
Examples: Coal, petroleum, natural gas, firewood.	Examples: Solar energy, wind energy, biogas, tidal energy.
Availability is limited.	Availability is abundant and sustainable.

3. What are conventional sources of energy? Give two examples.

Answer: Conventional sources of energy are the traditional sources of energy that have been used by humans for a long time. Most of these sources are limited in quantity and may get exhausted after continuous use.

Examples:  Coal  and Petroleum .

4. Why non-conventional sources of energy are preferred over the conventional sources?

Answer: Non-conventional sources are preferred because they are renewable (inexhaustible) and eco-friendly, causing little to no pollution. Unlike conventional sources (coal, petroleum), they are abundant in nature (sun, wind, water) and free of cost once the equipment is installed. They also help in conserving fast-depleting fossil fuels for future generations and are more sustainable in the long run, making them ideal for meeting growing energy demands without harming the environment.

5. “Sun is the ultimate source of energy”. Justify this statement.

Answer: The Sun is called the ultimate source of energy because most sources of energy directly or indirectly come from it. Plants prepare food using sunlight, and animals depend on plants for energy. Fossil fuels like coal and petroleum are formed from plants and animals that originally got energy from the Sun. Wind energy is also produced due to uneven heating of the Earth by the Sun. Thus, the Sun is the main source of energy on Earth.

6. List some uses of nuclear energy.

Answer: Uses of nuclear energy are:

(i) Energy produced in a nuclear reactor can be harnessed to produce electricity.

(ii) Nuclear energy is also being used to power submarines and ship. Vessels driven by nuclear energy can sail for long periods without having to refuel.

(iii) Radioisotopes obtained as by-products in nuclear reactions are used in medicine, agriculture and research.

7. What are the hazards of producing nuclear energy?

Answer: The hazards of producing nuclear energy are:

(i) Radioactive Waste: It produces highly toxic nuclear waste that remains active for thousands of years, posing serious disposal challenges.

(ii) Radiation Leakage: Accidents or meltdowns can release harmful radiation into the environment, causing fatal diseases like cancer and genetic mutations.

(iii) Thermal Pollution: Discharge of hot water from nuclear plants harms aquatic life.

(iv) High Risk: Mismanagement or natural disasters can lead to catastrophic environmental and health disasters.

8. What do you mean by the energy crisis? List out the possible reasons.

Answer: Energy crisis is a situation in which the demand for energy becomes greater than its available supply, causing shortage of energy resources.

Possible reasons:

(i) Rapid increase in population.

(ii) Excessive use of conventional energy sources.

(iii) Limited availability of fossil fuels.

(iv) Industrialisation and urbanisation.

(v) Wastage and inefficient use of energy.

(vi) Slow development and use of alternative energy sources.

9. What measures should be taken to mitigate the problem of energy crisis in our country?

Answer: The following measures should be taken to reduce the problem of energy crisis in our country:

(i) Promote the use of non-conventional sources of energy such as solar and wind energy.

(ii) Conserve energy by avoiding unnecessary use.

(iii) Use energy-efficient appliances and technologies.

(iv) Reduce wastage of electricity and fuel.

(v) Encourage research and development of renewable energy sources.

(vi) Create public awareness about energy conservation.

10. Why should we save energy?

Answer: We should save energy because:

(i) Energy resources like coal and petroleum are limited and exhaustible.

(ii) Saving energy helps to reduce pollution and protect the environment.

(iii) It ensures availability of energy for future generations.

(iv) It reduces the cost of energy consumption.

(v) It helps in overcoming the energy crisis and supports sustainable development.

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