Exam-style question
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How does the second law of thermodynamics relate to heat engine efficiency?.
- A.It allows for 100% efficiency in ideal conditions
- B.It states that energy cannot be created or destroyed
- C.It limits the maximum efficiency of heat engines
- D.It ensures that all energy is converted to work
Model answer
What a good answer should say
- It limits the maximum efficiency of heat engines
Explanation
Why this works
The cause is the second law of thermodynamics, which establishes that energy transformations are not completely efficient. The mechanism is that this law implies that some energy will always be lost as waste heat during the conversion process.
The effect is that there is a theoretical maximum efficiency for heat engines, leading to the consequence that no engine can be perfectly efficient.
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