Question
Fig. 6.1 shows apparatus that is used to demonstrate some effects of the transfer of energy by radiation
The glass bulb painted matt black, the shiny glass bulb and the spaces above the liquid in the tube
all contain air.
The heater glows red when switched on. The heater is the same distance from each bulb.
(a) State the two types of radiation that are emitted by the heater
1
2
(b) Before the heater is switched on, the liquid levels in the glass tube are the same.
State and explain any changes in the liquid levels that take place when the heater is
switched on.
Answer/Explanation
Answer
(a) Visible / light and infra-red
(b) Any 4 of:
Level of water in left-hand tube falls and level of water in right-hand rises
Matt black bulb is a good absorber OR is better absorber than shiny bulb
Shiny bulb is a good reflector OR is better reflector than matt black bulb
temperature rises more in left-hand tube OR less in right-hand tube
Pressure rises more in left-hand tube OR less in right-hand tube
Air expands more in left-hand hand tube OR less in right-hand tube