A wire carrying a current is placed between the poles of a permanent magnet. The wire experiences a force.
What causes this force?
The wire is magnetised by the magnet, so it is pulled towards one pole
The magnetic field of the current interacts with the field of the magnet
The moving charges in the wire are attracted to the north pole only
The current heats the wire, so the wire expands across the field
48 exam-style questions on OCR GCSE Physics 4.2 Uses of magnetism, covering 4.2.1 The motor effect, 4.2.2 Fleming's left-hand rule, 4.2.3 The force on a current-carrying conductor, 4.2.4 The electric motor, 4.2.5 Electromagnetic induction, 4.2.6 Alternators and dynamos, 4.2.7 How transformers work, 4.2.8 Transformer turns ratio, 4.2.9 Potential differences and turns in transformers, and 4.2.10 Microphones, loudspeakers and headphones. Each one has a worked solution and a mark scheme showing where the marks go.