Exam-style question
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Why do real heat engines fail to achieve 100% efficiency?.
- A.Due to the need for fuel
- B.Because of unavoidable energy losses
- C.Because they operate at low temperatures
- D.Due to the design of the engine
Model answer
What a good answer should say
- Because of unavoidable energy losses
Explanation
Why this works
The cause of real heat engines not achieving 100% efficiency is the unavoidable energy losses that occur during operation. The mechanism involves the conversion of energy where some is lost as waste heat due to friction and other inefficiencies.
The effect is that this loss reduces the amount of energy available for work, leading to the consequence that perfect efficiency is unattainable.
Common mistake
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