Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
Safety devices
17 practice questions
Practice questions
11–17 of 17
Question 11
4 marks · Normal
Answer and see the solution →The diagram below shows the inside of a UK mains plug.
Blank diagram of a UK mains plug for labelling (a)[2 marks]On the diagram, identify and label the live, neutral, and earth pins, as well as the fuse.
(b)[2 marks]Describe how the fuse protects the user from electric shock.
Question 12
4 marks · Normal
Answer and see the solution →A student notices that some hairdryers have a plastic casing, while others have a metal casing and an earth wire.
(a)[2 marks]Explain why appliances with a metal casing must be earthed.
(b)[2 marks]Describe how the earth wire and fuse work together to protect the user if a fault occurs inside a metal-cased appliance.
Question 13
1 mark · Normal
Answer and see the solution →Which part of the plug ensures that the user does not get an electric shock if the live wire touches the casing?
- A.The earth wire
- B.The live wire
- C.The neutral wire
- D.The brass pins
Question 14
4 marks · Normal
Answer and see the solution →A kitchen kettle is fitted with a 13 A fuse. The table below shows the fuses available and their ratings:
Fuse ratings for domestic use Fuse Rating (A) A 3 B 5 C 13 (a)[2 marks]Explain why the fuse should be rated just above the normal working current of the kettle.
(b)[2 marks]State and explain what would happen if someone used the 3 A fuse instead of the 13 A fuse in the kettle.
Question 15
4 marks · Normal
Answer and see the solution →The diagram below shows a lamp connected to the mains supply with a metal casing. The circuit includes a fuse and an earth wire.
(a)[1 mark]A simple mains circuit with metal-cased lamp (b)[3 marks]Explain what happens if a fault causes the live wire to touch the metal casing of the lamp.
Question 16
4 marks · Normal
Answer and see the solution →A manufacturer decides to use a plastic casing for a new electric hand mixer. The mixer is labeled 'double insulated'.
(a)[2 marks]Describe what is meant by double insulation in this context.
(b)[2 marks]Explain why an earth wire is not needed for this appliance.
Question 17
3 marks · Normal
Answer and see the solution →An electric fan develops a fault and starts drawing a current much higher than normal. It is fitted with a fuse in the plug.
(a)[2 marks]Explain how the fuse protects the circuit and user in this situation.
(b)[1 mark]Describe what must be done before the fan can be used again after the fuse blows.