Electricity Part 2

Question 1

What is alternating current?

Answer 1

Current that changes direction periodically.

Question 2

What is direct current?

Answer 2

Current that flows in one direction only.

Question 3

What is the potential difference of the mains supply?

Answer 3

230V

Question 4

What is the frequency of the mains supply?

Answer 4

50Hz

Question 5

Why do all appliances have a plug?

Answer 5

This allows a safe way of connecting the appliance to the mains electricity supply.

Question 6

State the function of the live wire.

Answer 6

It carries the alternating p.d. from the supply.

Question 7

State the function of the neutral wire.

Answer 7

It completes the circuit.

Question 8

State the function of the earth wire.

Answer 8

It’s a safety wire to stop the appliance becoming live.

Question 9

What colour is the live wire?

Answer 9

Brown

Question 10

What colour is the neutral wire?

Answer 10

Blue

Question 11

What is the p.d. between the live and neutral wire?

Answer 11

230V

Question 12

What is the p.d. between the live and earth wire?

Answer 12

230V

Question 13

What is the p.d. between the neutral and earth wire?

Answer 13

0V

Question 14

Explain why a person could receive an electric shock if they were working with the live wire. (3)

Answer 14

• The person has a p.d. of 0V as they are connected to the earth, and the live wire has a p.d. of 230V.
• Therefore, the p.d. between the person and the live wire is 230V.
• So when the person touches the live wire, they receive an electric shock.