A generator at an offshore wind farm produces electricity at a potential difference of 850 V850\text{ V}850 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 850 V850\text{ V}850 V. The potential difference across the secondary coil is 34000 V34000\text{ V}34000 V. The current in the primary coil is 1200 A1200\text{ A}1200 A.
Calculate the current in the secondary coil, assuming the transformer is ideal (100%100\%100% efficient).
Another transformer at an onshore substation has a power input of 135000 W135000\text{ W}135000 W to its primary coil. The current in this primary coil is 750 A750\text{ A}750 A.
Calculate the resistance of this primary coil. Use the equation: $\text{Power} = (\text{current})^2 \times \text{resistance}$