8) Electricity in the home

What are the two types of electricity supply?

Alternating current (AC) and direct current (DC).

What is alternating current (AC) and where is it commonly used?

AC is current that constantly changes direction, commonly used in the UK mains supply at around 230 V.

What frequency is the UK mains AC supply?

50 Hz (50 cycles per second).

What type of current do batteries and cells provide?

Direct current (DC), which flows in a single direction.

What are the three types of wires in a typical UK mains cable, and their colors?

Live wire (brown), neutral wire (blue), and earth wire (green and yellow).

What is the role of the live wire?

It provides the alternating potential difference (230 V) from the mains supply.

What is the function and color of the neutral wire?

It completes the circuit and is blue, with around 0 V potential.

What is the purpose of the earth wire?

It provides safety by preventing the appliance casing from becoming live, carrying current only in case of a fault.

Why can the live wire give an electric shock even if the switch is off?

Because there's still a potential difference in the live wire, and contact with it can allow current to flow through a body to the earth.

Why is a connection between live and earth dangerous?

It creates a low resistance path, allowing a large current to flow, which can cause serious injury or damage.