Question 1Multiple choice · 1 markA* challenge
An electric heater is rated at 600 W, 230 V.
Which fuse should be fitted in its plug?
- A 3 A
- B 5 A
- C 13 A
- D 30 A
Show answer
Answer: A
Free Electrical safety questions for IGCSE Physics (0625), part of Electricity & magnetism. Each question has the answer and the marking points an examiner would look for.
Generate a full Electrical Safety worksheet →All Electricity & magnetism questionsAn electric heater is rated at 600 W, 230 V.
Which fuse should be fitted in its plug?
Answer: A
Why is it dangerous to use electrical appliances with wet hands?
Answer: D
Some appliances are double insulated.
Explain what double insulated means.
Explain why the switch is placed in the live wire.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | casing non-conducting so no earth needed the casing is made of an insulating material (plastic) B1 so it cannot become live and no earth wire is needed B1 | 2 |
| (b) | off means appliance not live when switched off, the appliance is disconnected from the live wire B1 so it is not at a high voltage B1 | 2 |
An electric kettle is rated 2400 W, 230 V.
Calculate the current in the kettle when it is working normally.
Fuses of 3 A, 5 A and 13 A are available. State which fuse should be fitted and explain why.
The kettle is used for 2.5 hours each week. Electrical energy costs 20 cents per kWh. Calculate the weekly cost.
State two hazards of using electrical appliances in a damp bathroom, or with damaged insulation.
Explain why a circuit breaker is preferred to a fuse in many modern homes.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 10.4 A I = P/V = 2400/230 C1 10.4 A A1 | 2 |
| (b) | 13 A 13 A B1 the lowest rating above the normal current B1 | 2 |
| (c) | 120 cents energy = 2.4 kW × 2.5 h = 6.00 kWh C1 × 20 = 120 cents A1 | 2 |
| (d) | water conducts — shock; exposed wires — shock / fire water lowers resistance so electric shock more likely B1 damaged insulation exposes live wires (shock / fire) B1 | 2 |
| (e) | acts faster; can be reset it switches off more quickly B1 it can be reset rather than replaced B1 | 2 |
A kettle has a metal case connected to the earth wire.
Explain how the earth wire and fuse protect a user if the live wire touches the case.
State two hazards of using electrical appliances.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | large current to earth, fuse melts a large current flows from the live wire through the case to earth B1 this current melts the fuse B1 the circuit is broken so the case is not live B1 | 3 |
| (b) | damaged insulation; overheating cables; damp conditions Any 2 of: any two: damaged insulation; overheating of cables; damp conditions; excess current from overloaded sockets B2 | 2 |
A circuit breaker can be used instead of a fuse.
Explain one advantage of a circuit breaker.
A heater has a power of 2.3 kW and runs from 230 V. Calculate the current and choose a suitable fuse from 3 A, 5 A and 13 A.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | resets; faster it can be reset easily / it acts faster B1 | 1 |
| (b) | 10 A; 13 A I = P ÷ V = 2300 ÷ 230 C1 10 A A1 13 A fuse A1 | 3 |
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