class 8 ICSE HEAT

In gases increase in volume is directly proportional to its original

• Length

• Breath

• Height

• All

Mechanical clocks have pendulum which are made up of alloy of iron and nickel called as

• Brass

• Alnico

• Invar

• Steel

The increase in length of a rod on heating depends on

• its initial length

• its rise in temperature

• its material

• all the above

Why does a piece of ice when touched with hand appear cold?

• Because ice loses heat to hand.

• Because hand loses heat to ice.

• Because on touching ice, it melts to water at 0^oC.

• Because temperature of ice is very low.

Conversion of ice into water is an example of

• Evaporation

• Freezing

• Sublimation

• Melting

The process in which a substance changes its state from liquid to vapour state at fix temperature

• Boiling

• Freezing

• Sublimation

• Evaporation

The process in which a substance changes its state from liquid to vapour state at all temperature is

• Boiling

• Freezing

• Sublimation

• Evaporation

If on heating a solid, the increase in breadth and thickness is negligible (or radius) as compared to length, it is called as

• Superficial expansion

• Volume expansion

• Linear expansion

• Liquid expansion

Which of these process involves all the atoms and molecules

• Evaporation

• Boiling

• Both

• None

Which of these process is a surface phenomenon

• Evaporation

• Boiling

• Freezing

• Cooling