A new transmission route must carry an electrical power of 12 MW12\ \mathrm{MW}12 MW through a cable of resistance 3.0 Ω. The power can be transmitted at a potential difference of either 150 kV150\ \mathrm{kV}150 kV or 300 kV300\ \mathrm{kV}300 kV.
Calculate the power dissipated in the cable at each transmission potential difference.
Explain which transmission potential difference should be chosen to reduce energy dissipation in the cable.
108 exam-style questions on Edexcel GCSE Physics 13.2 Transformers and the National Grid, covering 13.2.1 Transformers and induction, 13.2.2 The transformer turns-ratio equation, 13.2.3 The National Grid, 13.2.4 The transformer power equation, and 13.2.5 Advantages of high-voltage transmission. Each one has a worked solution and a mark scheme showing where the marks go.