A weather station uses rotating cups to drive a small alternator. The magnetic field strength and the area of the coil are unchanged when the alternator is modified.
Measurements made at the same wind speed are shown in the table.
| Quantity | Original alternator | Modified alternator |
|---|---|---|
| Rotation rate in rotations per second | 30 | 30 |
| Number of turns on the coil | 240 | to be calculated |
| Peak potential difference in V | 3.6 | 9.0 |
Calculate the number of turns required on the coil of the modified alternator.
Explain why this modification increases the peak potential difference while leaving the output frequency unchanged.
92 exam-style questions on Edexcel GCSE Physics 13.1 Inducing a current, covering 13.1.1 Producing an electric current by induction, 13.1.2 Factors affecting the induced potential difference, 13.1.3 Alternators and dynamos, and 13.1.4 Microphones and loudspeakers. Each one has a worked solution and a mark scheme showing where the marks go.