Energy Resources and Energy Transfers
4 marks · EasySolar heating panels are used to heat water in some homes.
Name the main process by which energy from the Sun reaches the panels.
State what colour and finish (shiny/dull) is best for the surface of the panel for maximum absorption of energy. Give a reason.
Explain how the water inside is heated using energy from the Sun.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Radiation
(b) Matt black (dull black) surface. Reason: matt black absorbs more radiation. · must show black, matt/dull, absorbs radiation
(c) The surface absorbs radiation, heats up, and transfers energy to the water by conduction. · must show water heated by contact
Common mistakes: Confusing radiation with conduction/convection
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States 'radiation' (or 'infrared radiation').
B1 (b) · 1 mark · Gives correct surface: 'matt black' or 'dull black'.
B1 (b) · 1 mark · Correct reason: 'absorbs radiation' or similar.
B1 (c) · 1 mark · Explains heat transfers to water by conduction.
Worked solution
a) The main process is radiation.
b) The best surface is matt black (dull black) because it absorbs the most radiation.
c) The absorbed energy heats the panel, which then heats the water by conduction.