1. The process of burning a substance in the presence of oxygen is called:
A. Respiration
B. Combustion
C. Evaporation
D. Condensation

2. The substance that burns during combustion is called:
A. Product
B. Fuel
C. Catalyst
D. Residue

3. Which gas is necessary for combustion?
A. Nitrogen
B. Oxygen
C. Carbon dioxide
D. Hydrogen

4. The lowest temperature at which a substance catches fire is called:
A. Boiling point
B. Ignition temperature
C. Melting point
D. Freezing point

5. Which of the following is a combustible substance?
A. Stone
B. Sand
C. Wood
D. Glass

6. Which of the following is a non-combustible substance?
A. Paper
B. Coal
C. Iron nail
D. Wood

7. The burning of LPG in a gas stove is an example of:
A. Rapid combustion
B. Spontaneous combustion
C. Explosion
D. Slow combustion

8. Which type of combustion occurs without an external flame?
A. Rapid combustion
B. Spontaneous combustion
C. Explosion
D. Artificial combustion

9. Forest fires are examples of:
A. Rapid combustion
B. Spontaneous combustion
C. Explosion
D. Controlled combustion

10. Firecrackers produce energy in the form of:
A. Heat
B. Light
C. Sound
D. All of these

11. An explosion produces:
A. Heat slowly
B. Heat and sound suddenly
C. Only light
D. Only smoke

12. A good fuel should produce:
A. Less heat
B. Maximum heat
C. No heat
D. Smoke only

13. Which of the following is a gaseous fuel?
A. Coal
B. Petrol
C. LPG
D. Wood

14. Which of the following is a liquid fuel?
A. Petrol
B. Coal
C. Wood
D. Coke

15. Which of the following is a solid fuel?
A. LPG
B. Natural gas
C. Coal
D. Petrol

16. The amount of heat produced by burning 1 kg of fuel is called:
A. Ignition value
B. Calorific value
C. Heat index
D. Thermal unit

17. The unit of calorific value is:
A. Joule
B. Kilojoule per kilogram
C. Newton
D. Watt

18. Which fuel has a higher calorific value?
A. Cow dung cake
B. Coal
C. Petrol
D. Wood

19. The visible part of fire is called:
A. Heat
B. Flame
C. Gas
D. Spark

20. A candle flame has:
A. One zone
B. Two zones
C. Three zones
D. Four zones