A student keeps the same primary coil and iron core while testing different secondary coils. The input supply drifts between readings.
The table shows two tests of the ideal transformer.
| Test | Primary potential difference / V\mathrm{V}V | Secondary turns | Secondary potential difference / V\mathrm{V}V |
|---|---|---|---|
| X | 6.0 | 200 | 3.0 |
| Y | 4.0 | 600 | 6.0 |
Which conclusion is supported by these results?
The primary has 400 turns; the smaller voltage rise disproves the turns-ratio equation.
The primary has 400 turns; the smaller voltage rise is explained by the supply change.
The primary has 100 turns; the smaller voltage rise is explained by the supply change.
The primary has 100 turns; the smaller voltage rise disproves the turns-ratio equation.
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.