Physics 9702 · AS & A Level · Energy conservation

Energy conservation — practice question

The details below come from a test carried out on a petrol engine in a motor car. Power delivered: $150\,\text{kW}$ Fuel use: $20\,\text{litres per hour}$ Fuel energy content: $40\,\text{MJ per litre}$ Which expression can be used to find the efficiency of the engine?

  • A$\dfrac{150 \times 10^3}{40 \times 10^6 \times 20 \times 60 \times 60}$
  • B$\dfrac{150 \times 10^3 \times 60 \times 60}{20 \times 40 \times 10^6}$
  • C$\dfrac{150 \times 10^3 \times 40 \times 10^6 \times 20}{60 \times 60}$
  • D$\dfrac{150 \times 10^3 \times 20}{40 \times 10^3 \times 60 \times 60}$

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