An ideal transformer transfers energy from an alternating current supply to a laboratory heating element. The measurements are shown in the table.
| Coil | Potential difference | Current |
|---|---|---|
| Primary | 240 V | 1.5 A |
| Secondary | 60 V | 6.0 A |
The potential difference across the heating element is lower than the potential difference across the primary coil. Why is the electrical power transferred to the heating element not lower?
The secondary current is four times the primary current, while the potential difference is a quarter.
The secondary coil has fewer turns, so each turn transfers more power to the heating element.
Power depends only on current, so the 6.0 A secondary current prevents the power from decreasing.
The heating element receives energy from both coils, so the primary coil supplies the remaining power.
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.