Electricity in the Home

Question 1

True or false? The frequency of the UK mains electricity supply is 230 Hz

Answer 1

False

The frequency of the UK mains supply is 50 Hz; the potential difference is 230 V

Question 2

What is the potential difference between the live wire and the earth wire in an electrical appliance that’s turned on?

Answer 2

230 V

Question 3

What is the difference between an alternating current and a direct current?

Answer 3

An alternating current is constantly changing direction, whereas a direct current always flows in the same direction

Question 4

Briefly describe the functions of the live and neutral wires in an electrical appliance.

Answer 4

The live wires carries the (alternating) voltage, and the neutral wire completes the circuit to allow current to flow in the appliance.

Question 5

Why should a switch be connected in the live wire of a circuit?

Answer 5

A switch should be connected in the live wire so that the circuit can be broken, cutting off the live supply from the mains and reducing the risk of an electric shock.

Question 6

A hairdryer is plugged into the mains electricity supply but the hairdryer is switched off. Is it dangerous to touch the hairdryer’s live wire? Explain your answer.

Answer 6

Yes, it is still dangerous. A current isn’t flowing but there’s still a potential difference across the live wire. If you made contact with the live wire, your body might provide a link between the supply and the earth, so a large current could flow through you. This would cause an electric shock which could injure or kill you.