A transformer removed from a railway signalling cabinet has two coils, A and B. Coil A has 600 turns. The maintenance record gives two possible values for coil B: 200 turns or 1800 turns.
For each test, one coil is connected to an alternating supply and the output potential difference is measured across the other coil. The supply setting is changed between the tests. The coil connected to the supply in test 2 was not recorded.
| Test | Coil connected to the alternating supply | Input potential difference / V\mathrm{V}V | Output potential difference / V\mathrm{V}V |
|---|---|---|---|
| 1 | A | 12.0 | 4.0 |
| 2 | not recorded | 6.0 | 18.0 |
Which conclusion is supported by these results?
Coil B has 1800 turns; coil B was connected to the alternating supply in test 2.
Coil B has 200 turns; coil A was connected to the alternating supply in test 2.
Coil B has 200 turns; coil B was connected to the alternating supply in test 2.
Coil B has 1800 turns; coil A was connected to the alternating supply in test 2.
108 exam-style questions on Edexcel GCSE Physics 13.2 Transformers and the National Grid, covering 13.2.1 Transformers and induction, 13.2.2 The transformer turns-ratio equation, 13.2.3 The National Grid, 13.2.4 The transformer power equation, and 13.2.5 Advantages of high-voltage transmission. Each one has a worked solution and a mark scheme showing where the marks go.