2024 · M/J · 5054/21 | Q5

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Question (5 of 8)11 marks · Practise this topic →

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(a)Complete Fig. 5.1 by drawing the symbol for a fuse in the gap in the circuit.

Fig. 5.1 — see the question text for what it shows

Answer guidance

Complete Fill in every gap. A partly completed answer usually scores partly.

[1 mark]

(b)(i)On Fig. 5.2 sketch a current−voltage graph for a filament lamp.

Fig. 5.2 — see the question text for what it shows

[1 mark]

A current−voltage graph is sketched for a filament lamp.

(b)(ii)Explain the shape of the current−voltage graph drawn in (i).

Answer guidance

Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.

[2 marks]

(c)Calculate the current at point P in the circuit shown in Fig. 5.1.

Answer guidance

Calculate Show your working. The method can earn marks even when the final value is wrong, and a bare answer often cannot.

[3 marks]

In the circuit of Fig. 5.1, a 240 V mains supply is connected through a fuse to a lamp and two heaters of resistance 40 Ω and 60 Ω in parallel. The current in the lamp is 1.5 A (the heaters take 6.0 A and 4.0 A respectively).

(d)(i)Suggest a suitable fuse rating for the fuse.

Answer guidance

Suggest More than one answer may be acceptable, so long as it is consistent with the physics.

[1 mark]

A fuse is fitted in a mains circuit supplying a lamp and two heaters, where the total current is about 11.5 A.

(d)(ii)Explain why a fuse rating much larger than the value suggested in (i) is not suitable.

Answer guidance

Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.

[2 marks]

(d)(iii)Explain why it is necessary to connect a fuse in the live wire rather than the neutral wire or earth wire.

Answer guidance

Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.

[1 mark]

5054/21/M/J/24Cambridge O Level Physics 5054 · May/June 2024 · Paper 2 variant 1 · Question 5