A motor turns a carousel carrying laboratory sample tubes. An engineer is choosing a replacement coil. The magnetic flux density and coil dimensions are unchanged between the two coils. For this comparison, the turning effect is proportional to the number of turns multiplied by the current.
| Coil | Number of turns | Current / A\mathrm{A}A |
|---|---|---|
| Existing | 24 | 0.75 |
| Replacement | 36 | to be determined |
The replacement coil must produce a turning effect at least 25% greater than that of the existing coil.
Calculate the minimum current needed in the replacement coil.
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.