IGCSE · 4 · multiple choice
Electricity and magnetism · Question 4
Electricity and magnetism · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- demanding
- Marks
- 1
- Topics
- 1
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multiple choice1 mark
An electric heater is rated at 230 V, 2.0 kW. Fuses of 3 A, 5 A, 10 A and 13 A are available. Which is the most suitable fuse for the heater?
- A
3 A
- B
5 A
- C
10 A
- D
13 A
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Answer overviewCorrect answer: C — 10 A
01
1 markAnswer and reasoning
How to approach it
Predict from the governing principle before looking for a matching option. Then reject alternatives by checking direction, units, limiting behaviour or the physical meaning of each statement.
- 1
The correct choice is C: 10 A
- 2
The working current is 2000 / 230 = 8.7 A, so the fuse must be the smallest standard rating above it. A and B are below the working current and would melt every time the heater was switched on. D would carry the working current safely but is so far above it that a fault current of 12 A — enough to overheat the flex — would flow without ever blowing the fuse.
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