Chapter 9 - Energy Resources
(A) What resource will have to be used for the following work –
(1) Rohan wants to fly a kite.
Ans: Wind
(2) People in an Adivasi hamlet have to be protected from the cold.
Ans: Wood
(3) Cooking on a picnic.
Ans: Wood
(4) Salma wants to iron her clothes.
Ans: Electricity
(5) Starting a railway-engine.
Ans: Thermal Energy
(6) Heating water for a bath.
Ans: Wood
(7) After sunset, making light available inside the house.
Ans: Wood or Electricity
(B) Answer the following questions.
(1) Which energy resource does man use the most? Why?
Ans: The energy resources that man use the most are coal and mineral oil. Coal is used for different purposes, such as cooking, in industries, at thermal power stations, etc. Mineral oil is in great demand and is used in thermal power generation.
(2) Why are energy resources needed?
Ans: We engage in various activities to fulfill our needs, for which we need energy. Many types of energy resources are available on earth. They are important as we use them for various purposes in industries, schools, businesses and transportation. It is also used in all day-to-day activities.
(3) Why do we need to use environment-friendly energy resources?
Ans: We help to conserve, protect, and maintain the environment when we use environment-friendly energy sources. This helps to reduce the environment’s degradation. Energy security, which is the need of the hour, will be provided through environmentally friendly resources in addition to promoting sustainable growth.
(C) Explain the differences using the points in the brackets.
(availability, environment-friendliness, advantages and drawbacks)
(1) Mineral oil and solar energy
Ans:
| Points | Mineral oil | Solar energy |
|---|---|---|
Availability | It is limited in nature as it is found deep inside the ocean floor and Earth's surface. | Unlimited as it is obtained from the sun |
Environment-friendliness | Not environment friendly as it causes pollution. | Is environment friendly as it doesn't cause pollution . |
Advantages | Used in thermal and atomic Power generation. | Used in solar power generation. It is pollution free and helps in energy security. |
Drawbacks | It causes pollution and is highly inflammable. | It is very expensive to store this energy. |
(2) Hydel power and power from geo-thermal source
Ans:
| Points | Hydel power | Power from geo-thermal source |
|---|---|---|
Availability | The water used in generating power can still be used again. | Underground heat is utilized to generate power and is inexhaustible. |
Environment-friendliness | Hydel power does not cause any degradation of the environment. | They cause minimum pollution. |
Advantages | Reuse of water is possible. Energy generation is pollution-free. | If used on a large scale and more efficiently it may reduce global warming. |
Drawbacks | When water is not available it can’t produce electricity. Humans, flora, and fauna may lose natural habitat when hydel power plants are set up. | Only a few sites have the potential to establish geothermal power plants. High installation cost is involved. The energy generation capacity is too small |