A remote observatory is supplied with electrical power through a long cable of total resistance 4.0 Ω. The power entering the cable is 1.65 MW1.65\ \mathrm{MW}1.65 MW.
The operator can transmit this power at either of two potential differences.
| Operating mode | Transmission potential difference |
|---|---|
| A | 11 kV11\ \mathrm{kV}11 kV |
| B | 33 kV33\ \mathrm{kV}33 kV |
The observatory is supplied for 30 minutes.
Calculate the extra energy delivered to the observatory in this time when mode B is used instead of mode A.
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.