Induced magnetism
4 marks · NormalFigure 1 shows a bar magnet and two identical iron nails hanging from it as in an experiment.
Explain why nail 1 is able to hang from the bar magnet.
Explain why nail 2 is able to hang from nail 1.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) The magnetic field of the bar magnet induces magnetism in nail 1, making it temporarily magnetised and able to stick to the magnet.
(b) Nail 1, now magnetised, induces magnetism in nail 2, so nail 2 acts like a mini-magnet and can be attracted and hang from nail 1.
Must show: Correct geometry diagram
Common mistakes: Not mentioning induced magnetism in nail 1
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Mentions the magnetic field of the bar magnet induces magnetism in nail 1.
A1 (a) · 1 mark · Explains this allows nail 1 to stick to bar magnet.
M2 (b) · 1 mark · States nail 1 is now acting as a magnet (induced magnetism in nail 1).
A2 (b) · 1 mark · Explains nail 2 is magnetised by nail 1 (induced again) and attracted to it.
Worked solution
a) The strong magnetic field at the end of the bar magnet induces magnetism in nail 1. Nail 1 becomes temporarily magnetised, with its top acting as the opposite pole to the bar magnet, so it is attracted and hangs.
b) Nail 2 becomes magnetised by the magnetic field of nail 1, which is itself acting as a temporary magnet, allowing nail 2 to hang from nail 1.