Question
Four metal mugs with lids each contain the same volume of hot water at the same temperature.
The mugs are made from the same metal and are the same shape and size, but each has its outside surface painted with a different combination of texture and colour.
Which mug radiates thermal energy at the fastest rate?
A the mug painted shiny white
B the mug painted dull white
C the mug painted shiny black
D the mug painted dull black
Answer/Explanation
Ans: D
Question
A hot metal plate is placed near to a cold metal plate. Infra-red radiation transfers thermal energy between the two plates.
Which choice of colour causes the temperature of the cold plate to increase most slowly?
| hot plate | cold plate |
A | matt black | matt black |
B | matt black | shiny white |
C | shiny white | matt black |
D | shiny white | shiny white |
Answer/Explanation
Ans: D
Question
Four identical metal plates are painted either black or white and have either a dull or a shiny surface.
They are heated to the same temperature.
Which plate radiates thermal energy at the greatest rate?
A the plate that is dull and black
B the plate that is dull and white
C the plate that is shiny and black
D the plate that is shiny and white
Answer/Explanation
Ans: A