Electricity in the home

Question 1

What are the two types of electricity supplies ?

Answer 1

Alternating current and direct current

In ac supplies, the current is constantly changing direction . Alternating current is produced by alternative voltages in which the + and - ends keep alternating.

Question 2

UK mains supply

Answer 2

ac supply at around 230 V and frequency of ac main supply is 50 Hz

Question 3

What is direct current and what supplies it ?

Answer 3

Current flowing in one direction, created by direct voltage and cells, batteries supply DC.

Question 4

Read the following

Answer 4

Most electrical appliances connected to main supply by three core cables which means they have 3 wires inside each with a core of copper and coloured plastic coating

Colour on insulation of each cable shows its purpose - colour same for each appliance = easy to tell different wires apart

Question 5

Live wire

Answer 5

brown
live wire provides alternative pd from main supply

Question 6

Neutral wire

Answer 6

blue
wire completes the circuit , when appliance is operating normally, current flows through live and neutral wires. Around 0V

Question 7

Earth wire

Answer 7

Green and yellow
protect wire and for safety
Stops appliance casing from becoming live
Not carry current unless there’s a fault
at 0v

Question 8

The live wire can give you electric shock

Answer 8

1) You body is at 0v so if you touch live wire , large PD produces across body and current flows through you.

2) cause large electric shock which can injure or kill you
3) even if plug socket or light switch is turned off = there is still danger of an electric shock . Current is not flowing but PD remaining in live wire. If you make contact with live wire, your body provides link between supply and the earth so current would flow through you.
4) Any connection between live and earth can be dangerous. If the link create a low resistance path to earth, a huge current will flow = result in fire.