Exercises
(A) What resource will have to be used for the following work?
1. Rohan wants to fly a kite.
– Wind energy
2. People in an Adivasi hamlet have to be protected from the cold.
– Wood or coal
3. Cooking on a picnic.
– Firewood, gas, or solar energy
4. Salma wants to iron her clothes.
– Electricity
5. Starting a railway engine.
– Coal, diesel, or electricity
6. Heating water for a bath.
– Firewood, gas, electricity, or solar energy
7. After sunset, making light available inside the house.
– Electricity, solar energy, or oil lamps
(B) Answer the following questions.
1. Which energy resource does man use the most? Why?
- Man uses mineral oil the most because it is needed for vehicles, machines, industries, and daily activities.
2. Why are energy resources needed?
- Energy resources are needed to run machines, cook food, light homes, transport goods, and perform many activities in daily life.
3. Why do we need to use environment-friendly energy resources?
- We need to use environment-friendly resources because they do not pollute the air, water, or land and are available for a long time without harming nature.
(C) Explain the differences using the given points.
1. Mineral oil and solar energy:
- Availability: Mineral oil is limited, while solar energy is unlimited.
- Environment-friendliness: Mineral oil causes pollution; solar energy is clean.
- Advantages: Mineral oil gives quick energy; solar energy is renewable and free.
- Drawbacks: Mineral oil is expensive and causes pollution; solar energy depends on sunlight and needs costly technology.
2. Hydel power and power from the geo-thermal source:
- Availability: Hydel power is available near rivers; geo-thermal energy is available near hot water springs.
- Environment-friendliness: Both are clean and do not cause pollution.
- Advantages: Hydel power is easy to generate; geo-thermal energy is constant and does not depend on weather.
- Drawbacks: Hydel power needs dams, which can harm the environment; geo-thermal energy is not available everywhere.
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