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
Practise Edexcel GCSE Physics Transformers and the national grid with exam-style questions for Foundation and Higher tier. 47 questions, matched to the Edexcel GCSE Physics (1PH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.