Coal is a fuel which leaves behind a lot of ash after burning. The fuel should burn smoothly and at a steady rate. This is because if a fuel burns too fast, then most of the heat produced by it will be wasted. And if the fuel burns too slowly, then the heat produced may not serve our purpose. The fuels should have a low rate of evaporation at room temperature.
1. Which of the following leaves behind a lot of ashes after burning?
a. Coal
b. Petrol
c. CNG
d. None of these
2. The fuel should burn ........ and at a ....... rate.
a. smoothly, steady
b. rapidly, violently
c. smoothly, violently
d. None of these
3. If a fuel burns too fast, then most of the heat produced by it will be .......
a. Preserved
b. Wasted
c. May not serve our purpose
d. All of the above
4. If a fuel burns too slow, then most of the heat produced by it will .......
a. be preserved
b. be wasted
c. not serve our purpose
d. All of the above
5. The fuels would have ....... rate of evaporation at room temperature.
a. Low
b. High
c. Moderate
d. None of these
