Mains Electricity (Edexcel GCSE Physics)

Explain what is meant by the term A.C.

Figure 1 shows a kettle. The kettle uses A.C. current to heat water.

Figure 1

The kettle has a metal case. 

Explain why it would be dangerous for the live wire from the electric cable to touch the case of the kettle.

The kettle uses mains power to function. 

(i) State the potential difference of the UK main supply.

[1]

(ii) A label on the kettle says that its power output is 2.5 kW.

Show that the current in the kettle is about 11 A.

[2]

(i) State the relationship between voltage, current and resistance.

[1] 

(ii) Calculate the resistance of the kettle.

 resistance .......................................... Ω[2]

Figure 1 shows an incomplete table of the insulating cable colours for the wires in a UK plug.

Complete the table by filling in the missing information.

  Figure 1

An electric lamp contains a 3 A fuse.

Explain the role of the fuse within the circuit of the lamp.

Which of the diagrams shows a fuse which has been correctly connected to the circuit?

A	B
C	D

A battery-powered lawn mower uses direct current.

Which graph correctly shows direct current?

A	B
C	D

Electric lawnmowers are powered by the mains supply. An electric lawnmower is fitted with a 5 A fuse. 

Which row of the table correctly describes where the fuse should be fitted and how the fuse does its job? 

The owner of an electric lawnmower wants to install a circuit breaker to protect themself and the lawnmower from a surge in current.

Under normal operating conditions, the lawnmower draws a current of 4 A.

The manufacturer provides the graph shown in Figure 1 with the purchase of the circuit breaker.

Figure 1

Which row of the table correctly describes what will happen when the current is 4 A, and what will happen if the current rises to 14 A?   

Sam has a toaster and the fuse blows. Sam takes the fuse out and sees that it has 13 A written on it.

Sam doesn't have any 13 A fuses, but they have a 3 A fuse and decide to use that.

Describe what will happen when Sam switches on the toaster.

Sam buys a 13 A fuse for the toaster.

Figure 1 shows the possible positions to place the fuse in the circuit.

Figure 1

Which fuses show the correct position for the fuse?

As well as a fuse, the toaster is fitted with an earth wire as a safety feature.

Explain how the earth wire makes the toaster safe to use.

 Which of the following shows an A.C. circuit?

Which graph correctly shows an alternating current?

Figure 1 shows a circuit diagram for a D.C. circuit. The circuit contains a fuse.

Figure 1

Each of the ammeters reads 1.2 A.

Which option correctly describes the fuse that should be fitted to the circuit in this position?