A flexible copper power line is suspended horizontally between two test towers so that it is oriented at right angles (perpendicular) to a constant, uniform magnetic field.
When an alternating current (AC) is passed through the power line, the cable is observed to vibrate.
Explain why the magnetic force experienced by the power line changes in both magnitude and direction.
10 exam-style questions on Edexcel GCSE Physics 12.3 The motor effect. Each one has a worked solution and a mark scheme showing where the marks go.