A motor in a textile-winding machine completes a cycle in two stages. In this motor, the split-ring commutator changes the direction of the current in the coil twice during each complete revolution.
A counter records 156 changes in current direction during the complete cycle.
| Stage | Motor rotation rate | Duration |
|---|---|---|
| 1 | 1500 revolutions/min1500\ \mathrm{revolutions/min}1500 revolutions/min | 1.2 s |
| 2 | 720 revolutions/min720\ \mathrm{revolutions/min}720 revolutions/min | not recorded |
Calculate the duration of stage 2.
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.