Transfer of Thermal Energy
70 questions· page 1 of 7
Thermal energy passes quickly from hot regions of a metal to cold regions of the metal.
Why are metals good conductors of thermal energy?
Options
A Electrons in the metal vibrate about fixed points and quickly pass energy from one electron to the next.
B Electrons move quickly from ions in hot regions to ions in cold regions.
C Protons in the metal are close together and move quickly from hot to cold regions.
D Small ions of the metal move quickly from hot to cold regions through spaces in the metal lattice.
Which description of a dull black surface is correct?
Options
A good emitter, good absorber and good reflector of radiation
B good emitter, poor absorber and poor reflector of radiation
C good emitter, good absorber and poor reflector of radiation
D poor emitter, poor absorber and poor reflector of radiation
The diagram shows a metal pan on a hotplate.
The pan is heated by the hotplate.
How is the thermal energy transferred from the hotplate to the metal pan?
Options
A conduction
B convection
C diffraction
D refraction
A beaker of cold water is heated at its base.
What happens to the heated water?
Options
| density of heated water | movement of heated water | |
|---|---|---|
| A | decreases | no movement |
| B | decreases | upwards |
| C | increases | no movement |
| D | increases | upwards |
Four metal cans are identical except for the colour and the texture of their outer surfaces.
of water at is poured into each can.
Which can cools the most rapidly?
Options
Energy can be transferred by thermal radiation.
Four surfaces have different colours and textures. The surfaces are at equal temperatures and have equal surface areas.
Which surface transfers energy by thermal radiation at the fastest rate?
Options
A black and dull surface
B black and shiny surface
C white and dull surface
D white and shiny surface
Four copper spheres have identical surface colours and identical surface textures. They have different surface temperatures and surface areas.
Which sphere emits infrared radiation at the greatest rate?
Options
| surface temperature / | surface area / | |
|---|---|---|
| A | 500 | 120 |
| B | 500 | 480 |
| C | 1000 | 120 |
| D | 1000 | 480 |
A glass beaker contains water. When the centre of the base of the beaker is heated, a convection current is set up.
Which statement explains this?
Options
A The evaporation of water causes water molecules to rise to the surface.
B The expansion of water molecules causes them to rise to the surface.
C The water above the heat source rises because it becomes less dense.
D The water at the side falls because it becomes less dense.
A hot meal is supplied in a container made of shiny metal foil.
Why does the container help to keep the food hot?
Options
A The container traps air which increases convection.
B The foil is a poor thermal conductor.
C Shiny metal foil is a good absorber of infrared radiation.
D Shiny metal foil is a poor emitter of infrared radiation.
A piece of paper torn out of an exercise book is shown.
Which process is being described?
Options
A conduction
B convection
C evaporation
D radiation