You may use a calculator. You should show all your working and use appropriate units. Take the weight of 1.0 kg to be 9.8 N (acceleration of free fall = 9.8 m/s²).
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Fig. 7.1 shows a wire PQ between the poles of a magnet. The wire is horizontal and the current flows from left to right, as shown.
State the effect of the magnetic field on wire PQ. Include a direction in your answer.
Fig. 7.1 shows a horizontal, current-carrying wire PQ in the gap between the poles of a permanent magnet.
There is a magnetic field in the gap between the N pole and the S pole.
The current in PQ is from left to right.
Describe the effect of the magnetic field on PQ.
Answer guidance
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
[2 marks]
(a)(ii)
State the effect on PQ of increasing the strength of the magnetic field in the gap.
Answer guidance
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
[1 mark]
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Fig. 7.2 shows a torch with a magnet that can move through a coil. The torch has no battery. The magnet is shaken backwards and forwards through the coil.
Explain why an e.m.f. is induced in the coil.
Fig. 7.2 shows part of a torch. The torch does not contain a battery.
The torch is shaken and this causes the magnet to move backwards and forwards through the coil.
Explain why an electromotive force (e.m.f.) is induced across the coil when the magnet moves.
Answer guidance
Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.
[2 marks]
(b)(ii)
State one way to increase the e.m.f. induced.
Answer guidance
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
[1 mark]
(b)(iii)
As the magnet moves into the coil, the induced e.m.f. produces a current in the coil.
Explain how this opposes the motion of the magnet.
Answer guidance
Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.
[2 marks]
5054/02/SP/23Cambridge O Level Physics 5054 · Specimen 2023 · Paper 2 · Question 7