GCSE Standard Questions: Electricity in the Home
A student uses a hair dryer. The hair dryer's plug contains a fuse. The diagram below shows the fuse.
(a) Explain how the fuse prevents too large a current in the hair dryer.
A current gives heat energy to the wire when it passes through. If the current is too large for the fuse rating it will melt the wireand cause a break in the circuit - stopping current flow,
(b) The hair dryer is rated at 240 V, 1.5 kW. Calculate the current rating in amps of the hair dryer.
Power Rating = Voltage x Current
P = IV
I = P/V
I = 1500 /240 = 6.25 A
(c) The fuse in the hair dryer blows and the student has to replace it. The following fuses are available:
1A, 3A, 5A and 13A
(i) Which fuse should the student use?
(ii) Explain your choice.
The lower value fuses would blow as soon as the switch was closed.
(d) A hair dryer heats up air. Name one other example of electrical heating used in the home.
Any sensible answer:
Electric fire (to radiate heat into a room)
Fan heater to heat the air in the room
Kettle (to heat water)
(Total 9 marks)