Combustion and flame Class 8

What type of process is combustion?

• Physical process

• Metabolic process

• Chemical process

• None of the above

Can the process of rusting be considered as combustion?

• No, there is no heat or light produced

• Yes, it is considered to be rapid combustion

• Yes, there is little bit of heat produced and the process can be called slow combustion

• None of the above

Why is LPG considered the best fuel for cooking?

• It creates a luminous flame with more light and less heat.

• It creates a non-luminous flame with less light and more heat

• It is an eco friendly fuel

• Only option 2 and 3 are correct

Sodium is a metal which follows-

• Slow combustion

• Rapid combustion

• Complete combustion

• Spontaneous combustion

A material undergoes complete combustion when-

• It is yellow in colour and produces a luminous flame

• It is black in colour

• It is blue in colour and produces non-luminous flame

A person whose clothes caught fire is covered with blanket. Why is it so?

• To keep the person cold

• To stop the heat and light beimg emitted

• To hide the burnt body parts

• To cut off all air supply to extinguish the fire

LPG means

• Liquefied Petroleum Gas

• Liquefied Petrol Gas

• Liquid Petrol Godown

• Liquid Petroleum Gas

The substance which vapourises during burning gives ___________

• Light

• Heat

• Flame

• Ash

Fuel must be heated to its _______________ _______________ before it starts burning

• Melting point

• Ignition temperature

• Boiling point

• None of the above

The substances which have very low ignition temperature will

• Catch fire easily

• Will not catch fire

• Catch fire after some time

• None of the above