A straight wire carries a constant current in a uniform magnetic field. The wire is initially perpendicular to the field. It is turned until it is parallel to the field. What happens to the magnetic force on the wire?
It remains at its original value.
It decreases to zero.
It increases to twice its value.
It reverses at its original value.
86 exam-style questions on Edexcel GCSE Physics 12.3 The motor effect, covering 12.3.1 The motor effect, 12.3.2 Fleming's left-hand rule, 12.3.3 Force on a conductor, and 12.3.4 Electric motors. Each one has a worked solution and a mark scheme showing where the marks go.