Induced magnetism
2 marks · EasyExplain why induced magnetism in iron is useful for electromagnets.
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Because iron’s induced magnetism is temporary, it can be turned on and off when the current is switched on and off. This makes it suitable for use as the core of an electromagnet.
Also accept: Iron loses its magnetism quickly when the electromagnet is switched off, making it useful for devices like relays, bells, or circuit breakers.
Common mistakes: Saying steel is better for electromagnets.
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Marking points
B1 · 1 mark · Mentions temporary (not permanent) magnetism in iron.
B2 · 1 mark · Explains that the magnetism can be turned on/off with the magnetic field or current (suits electromagnets).
Worked solution
Induced magnetism in iron is temporary, so when the electromagnet is turned on, iron becomes magnetised, and when it’s off, the iron loses its magnetism. This controllability makes iron useful for electromagnet cores.