Physics 0625 · IGCSE · Energy, work and power

Energy, work and power — practice question

A lamp takes in a power input of $5.0\,\text{W}$. It loses $1.0\,\text{W}$ of power by heating the surroundings. Calculate the efficiency of the lamp.

  • A$20\%$
  • B$50\%$
  • C$80\%$
  • D$120\%$

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