Induced magnetism
3 marks · NormalExplain why a compass needle placed near a piece of iron that has been magnetised by a bar magnet will point in a particular direction. Refer to induced poles in your answer.
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A compass needle points in the direction of the magnetic field. When the iron is magnetised by the bar magnet, it develops induced poles: the end nearest the bar magnet becomes an opposite pole. The compass will point from the north pole of the bar magnet to the south pole induced on the iron, following the field direction.
Common mistakes: Saying the needle always points north; Ignoring induced poles
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Marking points
M1 · 1 mark · States a compass aligns with the magnetic field.
M2 · 1 mark · States that magnetisation creates induced poles in the iron.
A1 · 1 mark · Specifies compass points from the bar magnet's north pole to the induced south pole on the iron.
Worked solution
The compass aligns with the local magnetic field. The iron piece, when magnetised by a bar magnet, has induced poles so that the end near the bar magnet becomes a south pole. The compass needle points from the bar magnet's north pole toward the induced south pole on the iron, showing the direction of the magnetic field created.