Chapter 14 Sources of Energy Question 1: What is a good source of energy? Answer: A good source of energy fulfils the following criteria: (I)It produces a lot of heat per unit mass. (II) It does a huge amount of work per unit mass. (III) It is easily accessible. (IV) It is easy to store and transport. (V)It is economical. (VI)It produces less amount of smoke. Question 2: What is a good fuel? Answer: A good fuel produces a huge amount of heat on burning, does not produce a lot of smoke, and is easily available. Question 3: If you could use any source of energy for heating your food, which one would you use and why? Answer: Natural gas can be used for heating and cooking food because it is a clean source of energy. It does not produce huge amount of smoke on burning. Although it is highly inflammable, it is easy to use, transport, and it produces a huge amount of heat on burning. ...
Class–X (Our Environment) Questions 1. Why are some substances biodegradable and some non-biodegradable? 2. Give any two ways in which biodegradable substances would affect the environment. 3. Give any two ways in which non-biodegradable substances would affect the environment. Class–X (Our Environment) Answers 1. Substances which can be acted upon by microorganism (decomposer) are called biodegradable. For example- vegetable wastes, paper, cotton etc. On the other hand, materials which are not acted upon by decomposers are called non-b...