Practice question · Numerical answer
An engine absorbs 900 J from a hot reservoir and rejects 600 J to a cold one per cycle. Compute its efficiency as a percentage, to the nearest whole number.
Hints
- Efficiency is net work over heat absorbed, and net work is the difference of the two heats.
- Compute (900 - 600)/900 as a percentage.
Show the answer
33 (answers within ±1 count)
Why
, so 33 %. A third of the absorbed heat becomes work and two thirds is dumped.
Practise Cyclic Processes and the Carnot Cycle
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