The materials which are burnt to produce heat energy are known as fuels. Examples of fuels are : Wood, Coal, Cooking gas (LPG), Kerosene, Diesel and Petrol (see above figure). In our day to day life, the most important sources of energy are fuels. The usefulness of a fuel is measured in terms of its calorific value. Higher the calorific value, better the fuel will be. The amount of heat produced by burning a unit mass of the fuel completely is known as its calorific value. The unit of mass usually taken for measuring the calorific value of a fuel is "gram".
1. The materials which are burnt to produce heat energy are called
a. Non-renewable
b. Renewable
c. Fuels
d. None of these
2. In our daily life, most important sources of energy are
a. Fuels
b. Oceans
c. Biomass energy
d. None of these
3. Which of the following are fuels?
a. Coal
b. Petroleum
c. Wood
d. All of the above
4. The usefulness of a fuel is measured in terms of its ....
a. Amount
b. Colour
c. Calorific value
d. None of these
5. The unit of mass usually taken for measuring the calorific value of a fuel is
a. Kg
b. Litre
c. Gram
d. Metre
