Physics 9702 · AS & A Level · Energy conservation

Energy conservation — practice question

In many traditional filament lamps, for every $8\,\text{J}$ of light energy produced, as much as $92\,\text{J}$ of energy is released as thermal energy. What is the efficiency of the lamp, as the percentage of electrical energy converted to light energy?

  • A$8\%$
  • B$9\%$
  • C$91\%$
  • D$92\%$

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