O-LevelPhysicsMagnetism5054/21 · Oct/Nov 2021 · Q75 Marks

EITHER Fig. 7.1 shows a solenoid connected to an ammeter. [Figure 7.1] The S-pole of a permanent magnet moves into the left-hand end of the solenoid. The ammeter reading shows that there is a small positive current in the circuit.

(a)Explain why there is a current in the circuit when the magnet moves.[3]
(b)When the magnet is inside the solenoid, it stops moving. It is then pulled back out of the solenoid. Explain what happens to the ammeter reading as the magnet moves out of the left-hand end of the solenoid.[2]

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Mark scheme

Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.

[B1] magnetic field lines cut the solenoid / coils or changing magnetic field in solenoid
[B1] an electromotive force / e.m.f. is induced
[B1] electromotive force / e.m.f. produces the current
[B1] negative / opposite / reversed current / deflection / reading
[B1] negative e.m.f. / voltage (induced) or magnetic field cut in opposite direction or magnetic field changes in opposite sense / decreases (owtte)

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