Class 8 Combustion and flame

The substances which have very low ignition temperature will

• catch fire easily

• will not catch fire

• catch fire after some time

• none of these

CNG and LPG are the examples of

• solid fuels

• liquid fuels

• gaseous fuels

• they aren't fuels

what is combustion

• chemical process

• physical process

• none of these

• both a & b

Ignition temperature is

• Lowest temperature at which a substance catches fire

• Highest temperature at which a substance catches fire

• Any temperature

• 100⁰ C

Fuel may be

• Solid

• Liquid

• Gas

• All of the three

Combustion is a reaction in which a substance reacts with

• hydrogen

• Nitrogen

• Oxygen

• Chlorine

Water cannot be used as a fire extinguisher to put out

• Burning coal

• Electrical fires

• Burning wood

• Forest fires

Water is not used to control fires involving electrical appliances.

• False
• True

Substance which catch fire are called

• Acids

• Bases

• Burners

• Combustible

Essential requirements for producing fire are

• Fuel

• Air

• Heat

• All of these