A-LevelPhysicsWork, energy and power9702/12 · May/June 2015 · Q181 Mark

Water from a reservoir is fed to the turbine of a hydroelectric system at a rate of 500 kg s⁻¹. The reservoir is 300 m above the level of the turbine. The electrical output from the generator driven by the turbine is 200 A at a potential difference of 6000 V. What is the efficiency of the system?

A8.0%

B8.2%

C80%

D82%

✓ Correct answer

D: 82%

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Topic: Work, energy and power, A-Level Physics (syllabus 9702). Multiple choice, 1 mark.
Source: A-Level Physics, May/June 2015 Paper 1 Variant 2, question 18.

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