Class 8 Science Chapter 6 Combustion And Flame Quiz 3 (25 MCQs)

Quiz Instructions

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1. A fire can be controlled by
2. OBSERVE THE FOLLOWING STATEMENTS:1.) good fuel-very costly.2.) innermost zone of candle flame-black3.) calorific value of a fuel-kilojoule per kg (kJ / kg)4.) middle zone of candle flame-blueChoose the correct statements.
3. Combustion requires three elements:fuel, oxygen, and .....
4. What is the chemical process that takes place during the burning of candles?
5. Fuel must be heated to its ..... before it starts burning
6. Carbon fuels like wood, coal, petroleum release in burnt carbon particles dangerous pollutants causing respiratory problems.
7. Coal burns in air producing ..... , ..... , and .....
8. Good fuels have
9. Rapid Combustion occurs when .....
10. There are following zones of a flame
11. ..... of fuel forms poisonous carbon monoxide gas.
12. Define combustion .....
13. An ideal fuel is cheap, readily available, easily combustible and easy to transport. It has high calorific value. It does not produce gases or residues that pollute the environment. Based on the above statements which of the following is closest to being an ideal fuel?
14. What is fuel??
15. Burning of LPG is an example of
16. A combustible substance cannot catch fire or burn as long as its temperature is higher than its ignition temperature.
17. The hottest part of the flame
18. Combustion always results as flames
19. Substance that does not burn in air is
20. When water is poured over burning wood, the fire goes off. This is because
21. Unburnt carbon particles of the fuel cause
22. The substance which have very low ignition temperature will
23. A fuel gives yellow flame due to
24. Increased concentration of Carbon dioxide in the air causes .....
25. During the process of Combustion ..... is given out