Induced magnetism
2 marks · NormalA company wishes to make temporary electromagnets for use in a factory. They can choose between using iron and steel for the core.
Which material should they choose for the core, and why?
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They should choose iron, because it is magnetically soft and its induced magnetism disappears easily when the field is removed.
Also accept: iron, because it loses magnetism quickly
Common mistakes: Choosing steel, or saying iron stays magnetised
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Marking points
B1 · 1 mark · Chooses iron as the correct material.
M1 · 1 mark · Correctly explains iron's magnetically soft property leads to temporary magnetism only.
Worked solution
Iron should be used because it is magnetically soft; this means the induced magnetism disappears quickly when the current is switched off.