Physics 9702 · AS & A Level · Energy conservation

Energy conservation — practice question

An electric motor receives a total energy of $E$. A quantity of energy $Q$ is wasted, and the rest is used to do useful work. What is the efficiency of the motor?

  • A$\frac{Q}{E}$
  • B$\left(\frac{Q}{E}\right)-1$
  • C$1-\left(\frac{Q}{E}\right)$
  • D$\frac{(1-Q)}{E}$

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