An ideal step-up transformer at a power station is used to increase the potential difference from 15 kV15\text{ kV}15 kV to 300 kV300\text{ kV}300 kV for long-distance transmission. The power station inputs 45 MW45\text{ MW}45 MW of electrical power into the transformer. The total resistance of the transmission cables is 12 Ω.
What is the power dissipated as thermal energy in these transmission cables?
1.8 kW1.8\text{ kW}1.8 kW
21.6 kW21.6\text{ kW}21.6 kW
270 kW270\text{ kW}270 kW
108 MW108\text{ MW}108 MW
28 exam-style questions on Edexcel GCSE Physics 13.2 Transformers and the National Grid. Each one has a worked solution and a mark scheme showing where the marks go.