A railway points heater has four current settings.
| Setting | Current in A |
|---|---|
| A | 2.0 |
| B | 4.0 |
| C | 8.0 |
| D | 16.0 |
The heater's resistance is the same at every setting. At setting C, the power transferred by heating is 320 W. The power transferred by heating needs to be reduced to 80 W. What change of setting is needed?
It changes from setting C to setting B
It changes from setting C to setting A
It changes from setting C to setting D
It remains at setting C
96 exam-style questions on AQA GCSE Physics 7.3 Induced potential, transformers and the National Grid (HT only), covering 7.3.1 Induced potential (HT only), 7.3.2 Uses of the generator effect (HT only), 7.3.3 Microphones (HT only), and 7.3.4 Transformers (HT only). Each one has a worked solution and a mark scheme showing where the marks go.