A generator at a power station produces electricity at a potential difference of 1200 V1200\text{ V}1200 V. The generator is connected to a step-up transformer to transmit this electricity.
The potential difference across the primary coil of the transformer is 1200 V1200\text{ V}1200 V. The potential difference across the secondary coil is 48000 V48000\text{ V}48000 V. The current in the primary coil is 1600 A1600\text{ A}1600 A.
Calculate the current in the secondary coil, assuming the transformer is ideal (100%100\%100% efficient).
Another transformer has a power input of 635040 W635040\text{ W}635040 W to its primary coil. The current in this primary coil is 1260 A1260\text{ A}1260 A.
Calculate the resistance of this primary coil. Use the equation: \
\text{Power} = (\text{current})^2 \times \text{resistance}{\char"24}$39 exam-style questions on OCR GCSE Physics Powering Earth. Each one has a worked solution and a mark scheme showing where the marks go.