Physics 9702 · AS & A Level · Gravitational potential energy and kinetic energy

Gravitational potential energy and kinetic energy — practice question

Water from a reservoir is supplied to the turbine in a hydroelectric system at a rate of $510\,\text{kg s}^{-1}$. The reservoir lies $280\,\text{m}$ above the turbine level. The generator, which is driven by the turbine, produces an electrical output of current $205\,\text{A}$ at a potential difference of $5800\,\text{V}$. What is the efficiency of the system?

  • A$8.3\%$
  • B$12\%$
  • C$83\%$
  • D$85\%$

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