Ch7 Mains Electricity

Question 1

What does a fuse look like /contain

Answer 1

Usually in the form of a cylinder which contains a thin piece of wire made from a metal with a low melting point

Question 2

What happens if too large a current flows in a circuit to the fuse

Answer 2

The fuse becomes very hot and melts. The fuse blows, shutting off the circuit

Question 3

Is the wiring in a house designed to have a high or low resistance

Answer 3

A low resistance

Question 4

Is the heating element in kettles and toasters designed have a high or low resistance

Answer 4

High resistance

Question 5

What is the equation for power

Answer 5

Power = current X voltage

Question 6

What is the equation for energy

Answer 6

Energy = power X Time

Question 7

What do mains electricity and batteries provide-AC or DC current

Answer 7

Mains electricity supply AC

Cells and batteries provide DC

Question 8

What three wires to ring circuits are usually consist of

Answer 8

-Live wire:
provides the path along which the electrical energy from the powerstation travels. This wire is alternately positive and negative causing alternating current (AC) to flow along it
- neutral wire:
Completes the circuit
- Earth wire:
Usually has no current flowing through it. It is there to protect you if the appliance develops a fault