An electromagnet is used to lift scrap metal. The scrap metal must drop when the current is switched off.
Why is the core of the electromagnet made of iron and not steel?
Iron is a better conductor, so a larger current passes through the coil
Steel would keep much of its magnetism, so the scrap might stay attached
Steel is not a magnetic material, so it cannot become an induced magnet
Iron becomes a permanent magnet more easily, so it lifts heavier loads
44 exam-style questions on OCR GCSE Physics 4.1 Magnets and magnetic fields, covering 4.1.1 Magnetic poles, attraction and repulsion, 4.1.2 Permanent and induced magnets, 4.1.3 The magnetic field of a magnet, 4.1.4 Compasses and the Earth's magnetic field, 4.1.5 The magnetic field around a current-carrying wire, 4.1.6 Field strength, current and distance, and 4.1.7 Solenoids and electromagnets. Each one has a worked solution and a mark scheme showing where the marks go.