Fuel and Flame MCQs for CBSE
Fuel and Flame MCQs Class 8
Class: CBSE Class 8
Subject: Science
Section: Section 6 – Combustion and Flame
Topic: Fuel and Flame MCQs
Board: CBSE Board Examinations
Subject: Science
Section: Section 6 – Combustion and Flame
Topic: Fuel and Flame MCQs
Board: CBSE Board Examinations
1. A substance that burns to produce heat energy is called:
Answer: b) Fuel
Fuels release heat energy on burning and are used for cooking, transport and industries.
Fuels release heat energy on burning and are used for cooking, transport and industries.
2. Which of the following is a gaseous fuel?
Answer: c) LPG
Liquefied Petroleum Gas is stored in cylinders and burns cleanly.
Liquefied Petroleum Gas is stored in cylinders and burns cleanly.
3. The visible part of fire is called:
Answer: b) Flame
Flame is the region where burning vapours produce light and heat.
Flame is the region where burning vapours produce light and heat.
4. Which fuel is known as clean fuel?
Answer: c) LPG
It burns without smoke and leaves no residue.
It burns without smoke and leaves no residue.
5. The hottest zone of a flame is:
Answer: c) Outer non‑luminous zone
Complete combustion occurs here producing maximum heat.
Complete combustion occurs here producing maximum heat.
6. Yellow flame indicates:
Answer: b) Incomplete combustion
Unburnt carbon particles glow producing yellow light.
Unburnt carbon particles glow producing yellow light.
7. Blue flame indicates:
Answer: b) Complete combustion
Blue flame is clean and hottest.
Blue flame is clean and hottest.
8. Candle flame has how many zones?
Answer: c) Three
Inner dark, middle luminous, outer non‑luminous.
Inner dark, middle luminous, outer non‑luminous.
9. Fuel with highest calorific value is:
Answer: a) Hydrogen
It produces large heat and water as product.
It produces large heat and water as product.
10. Which fuel leaves maximum residue?
Answer: b) Wood
Solid fuels leave ash after burning.
Solid fuels leave ash after burning.
11. Ideal fuel should be:
Answer: d) All of these
Ideal fuel combines efficiency, safety and affordability.
Ideal fuel combines efficiency, safety and affordability.
12. Non‑luminous flame is preferred for cooking because:
Answer: c) It is hotter
Complete combustion produces more heat.
Complete combustion produces more heat.
13. Soot deposition occurs in:
Answer: b) Yellow flame
Unburnt carbon deposits as soot.
Unburnt carbon deposits as soot.
14. Which fuel is used in rockets?
Answer: b) Hydrogen
Hydrogen provides high thrust due to high calorific value.
Hydrogen provides high thrust due to high calorific value.
15. Flame forms when:
Answer: c) Vapours burn
Flame is produced by burning gaseous vapours.
Flame is produced by burning gaseous vapours.
16. Charcoal burns with:
Answer: b) No flame
It glows red without vapour formation.
It glows red without vapour formation.
17. Which fuel causes least pollution?
Answer: c) CNG
It burns cleanly with minimal harmful gases.
It burns cleanly with minimal harmful gases.
18. The middle zone of candle flame is:
Answer: b) Luminous
It glows yellow due to incomplete combustion.
It glows yellow due to incomplete combustion.
19. LPG is stored as:
Answer: b) Liquid under pressure
It vaporizes when released.
It vaporizes when released.
20. Fuel efficiency depends mainly on:
Answer: b) Calorific value
Higher calorific value fuels produce more heat per kg.
Higher calorific value fuels produce more heat per kg.
