MEDIUM
8th CBSE
IMPORTANT
Earn 100

Why are water and sand used to extinguish fires?

Important Questions on Combustion, Flame and Fuels

EASY
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>TRACK YOUR PROGRESS>Q 1
Substances which burn or catch fire easily are called as _____ substances. (combustible / non-combustible)
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?
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
Classify the fuels on the basis of their source.
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
LPG is better domestic fuel than wood give reasons.
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
Give reasons why Goldsmiths use the outermost zone of the flame for melting gold and silver?
MEDIUM
8th CBSE
IMPORTANT
Expanded Universal Science>Chapter 6 - Combustion, Flame and Fuels>ASSESSMENT ZONE>Q E
Give reasons why for any fuel to burn, it is essential to reach its ignition temperature?