Heat

A cup contains hot liquid. Some of the liquid evaporates. What happens to the mass and what happens to the weight of the liquid in the cup?

• A

• B

• C

• D

Which statement about evaporation is correct?

• A

• B

• C

• D

A pool of water evaporates. As molecules escape, the temperature of the water left in the pool changes. From where do the molecules escape and what is the effect on the temperature of the water in the pool? B

• A

• B

• C

• D

A liquid is heated in a beaker. The density of the liquid changes as its temperature increases. This causes energy to be transferred throughout the liquid. How does the density change and what is this energy transfer process? B

• A

• B

• C

• D

A rod is made half of glass and half of copper. Four pins A, B, C and D are attached to the rod by wax. The rod is heated in the centre as shown. The pins fall off when the wax melts. Which pin falls off first?

• A

• B

• C

• D

Which process involves convection?

• A

• B

• C

• D

A student suggests some uses for containers made from good thermal conductors and for containers made from poor thermal conductors. In which row are both suggested uses correct?

• A

• B

• C

• D

Two plastic cups are placed one inside the other. A small spacer keeps the two cups separated. Hot water is poured into the inner cup and a lid is put on top, as shown.

• A

• B

• C

• D

A solid is heated from room temperature. The graph shows how its temperature changes with time as it is heated constantly. At which time has it just become completely liquid?

• A

• B

• C

• D

Thermal energy travels through space from the Sun to the Earth. Space is a vacuum. How is thermal energy transferred from the Sun to the Earth?

• A

• B

• C

• D