Concept of Heat IGCSE

When the molecules of a substance vibrate faster, the

• Temperature reduces

• internal energy increases

• internal energy decreases

• molecules have lower potential energy

When a cold object is placed beside a hot one, heat flow is from

• Cold to hot

• hot to cold

• both cases as above

• nothing happens between them

Which of these is not synonymous with thermal agitation?

• Internal energy

• heat energy

• thermal energy

• gravitational energy

In which of these substances would the molecules vibrate fastest when exposed to same heat energy ?

• Diamond

• wood

• cotton wool

• mercury

Which of these is not a consequence of increase of heat energy?

• Expansion

• Change of state

• increase in temperature

• Change in mass

Change of state from ice to water is an example of the application of

• force

• heat

• light

• power

Which of these has the molecules expand most at same heat energy ?

• solid

• liquid

• gas

• all of the above

Change of state from steam to water is called

• Condensation

• melting

• sublimation

• deposition

Fusion is change of state from

• Liquid to solid

• solid to liquid

• liquid to gas

• gas to liquid

On which of the following is the design of the thermostat of an electric iron based?

• Apparent expansion of a body

• expansion of metals when heated

• change in resistance of a body on heating

• thermoelectric effect