GCSE Standard Questions: Electricity in the Home

A2.

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,

(2 marks)

(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

(4 marks)

(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?

13A

(1 mark)

The lower value fuses would blow as soon as the switch was closed.

(1 mark)

(d) A hair dryer heats up air. Name one other example of electrical heating used in the home.

Electric fire (to radiate heat into a room)

Fan heater to heat the air in the room

Kettle (to heat water)

Immersion heater

(1 mark)

(Total 9 marks)