A machine uses an electromagnet to separate steel pieces from other materials.
The electromagnet is made by winding many turns of wire tightly around an iron core. The wire normally has a thin plastic coating.
The coating is damaged, so the bare wire in several neighbouring turns touches. The current supplied to the electromagnet is kept the same.
Explain why the electromagnet produces a weaker magnetic field when the coating is damaged.
90 exam-style questions on AQA GCSE Physics 7.2 The motor effect, covering 7.2.1 Electromagnetism, 7.2.2 Fleming's left-hand rule (HT only), 7.2.3 Electric motors (HT only), and 7.2.4 Loudspeakers (HT only). Each one has a worked solution and a mark scheme showing where the marks go.