An offshore wave-energy converter transmits electrical energy to a coastal research platform at a potential difference of 16,000 V16,000\text{ V}16,000 V.
The energy transferred by the converter in one second is 920,000 J920,000\text{ J}920,000 J.
Calculate the charge flow from the wave-energy converter in one second. Use the equation:
charge flow=energypotential difference \text{charge flow} = \frac{\text{energy}}{\text{potential difference}} charge flow=potential differenceenergyThe electricity supply is stepped down to 400 V400\text{ V}400 V for use in the platform's analysis laboratory. The table below shows the electric current in three instruments when they are fully operational:
| Instrument | Current (A) |
|---|---|
| Telemetry transceiver | 4.25 |
| High-pressure pump | 8.50 |
| Ventilation fan | 3.25 |
Calculate the total power of all three instruments when running at the same time. Use the equation:
power=potential difference×current \text{power} = \text{potential difference} \times \text{current} power=potential difference×current44 exam-style questions on AQA GCSE Physics 1.1 Energy changes in a system, and the ways energy is stored before and after such changes, covering 1.1.1 Energy stores and systems, 1.1.2 Changes in energy, 1.1.3 Energy changes in systems, and 1.1.4 Power. Each one has a worked solution and a mark scheme showing where the marks go.