Physics (AS & A Level) · May / June 2018 · Paper 13 · Question 15

Water from a reservoir is fed to the turbine of a hydroelectric system at a rate of 510 kg s–1. The reservoir is 280 m above the level of the turbine. The electrical output from the generator driven by the turbine is a current of 205 A at a potential difference of 5800 V. What is the efficiency of the system?

1. A8.3%
2. B12%
3. C83%
4. D85%

As printed in the paper