Exam-style question
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An engine does 1500 J of work and receives 3000 J of energy. Calculate the efficiency of the engine.
- A.25%
- B.50%
- C.75%
- D.100%
Model answer
What a good answer should say
- 50%
Explanation
Why this works
The efficiency is determined by dividing the useful work output by the total energy input and multiplying by 100. The initial values are 1500 J (work done) and 3000 J (energy input).
The calculation yields an efficiency of 50%.
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