CIE iGCSE Co-Ordinated Science P2.3.3 Radiation Exam Style Questions Paper 2
Question
There is a vacuum in the space between the Sun and the Earth.
How is thermal energy transferred from the Sun to the Earth?
(A) by conduction only
(B) by convection only
(C) by radiation only
(D) by convection and radiation
▶️Answer/Explanation
Ans : C
Question
Which statement about thermal radiation is correct?
A A dull surface is a good absorber and a good reflector of thermal radiation.
B A dull surface is a poor absorber and a poor reflector of thermal radiation.
C A shiny surface is a good absorber but a poor reflector of thermal radiation.
D A shiny surface is a poor absorber but a good reflector of thermal radiation.
▶️Answer/Explanation
Ans : D
Question
Four identical metal cans contain equal quantities of water at 80 °C. The outer surfaces of two of the cans are dull and the outer surfaces of the other two cans are shiny. Lids are put on two of the cans. All the cans are allowed to cool. Which can cools the fastest?
▶️Answer/Explanation
Answer: A
Explanation: A dull surface radiates heat more effectively than a shiny surface, and a can without a lid loses heat faster due to convection. Therefore, the dull can without a lid cools the fastest.
Question
Three identical metal cans X, Y and Z are painted. X is painted dull black, Y is painted dull white and Z is painted shiny silver.
All three cans are filled with the same amount of water at 100°C. They are left in a cool room for the same amount of time.
Which row shows possible temperatures of the water in each of the cans after this time?
▶️Answer/Explanation
Answer: A
Explanation: The dull black can (X) will cool the fastest because it is the best emitter of infrared radiation. The shiny silver can (Z) will cool the slowest because it is the poorest emitter. Therefore, the temperatures will be X (lowest), Y (middle), and Z (highest).