GCSE Standard Questions: Electricity in the Home

Q15. Here is part of a lighting circuit in a house.:

(a) What is the frequency of the ac mains electricity supply in the UK?

50 Hz

[1 mark]

(b) The mains electricity supply has an alternating potential difference.

Which diagram shows an alternating potential difference? (Tick one box).

[1 mark]

The current in the lamp is 0.020 A.

Calculate the power output of the lamp.

P = IV

P = 0.020 x 230

P = 4.6 W

[3 marks]

(d) The potential difference across the lamp is 230 V.

Calculate the energy transferred by the lamp when 180 C of charge flows through the lamp.

E = QV

E = 180 x 230

E = 41,400 J

[3 marks]

(e) An electrician needs to replace the light switch in the circuit shown above.

Describe the possible hazard and the risk to the electrician when changing the light switch.

Hazard: live wire or high potential difference

Risk: electric shock or electrocution

[2 marks]

(Total 10 marks)