MEDIUM
8th CBSE
IMPORTANT
Earn 100

Suppose you are asked to cook rice using cow dung cake, coal and LPG as fuels. Which fuel would you prefer? Give your reason.

Important Questions on Combustion, Flame and Fuels

MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
Differentiate between combustible and non-combustible substances.
HARD
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
Identify and discuss the three main zones of the candle flame.
HARD
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
Mention five characteristics of an ideal fuel.
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
A candle produces a yellow flame on burning while LPG burning in a gas burner produces a blue flame. Explain.
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
Why are water and sand used to extinguish fires?
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
How does carbon dioxide help in extinguishing a fire?
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E

Study the details of the following fuels and select the best fuel out of them. Give reason.

Fuel Calorific Value Ignition Temperature
X 45,000 KJ/kg 350°C
Y 35,000 KJ/kg 750°C
Z 75,000 KJ/kg 750°C
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
What is the cause behind the colour change of the Taj Mahal from white to yellowish?