Rate of Heat Output to Low-Temp Res per Cycle: 450J

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SUMMARY

The discussion centers on calculating the rate of heat output to the low-temperature reservoir in a heat engine with an efficiency of 25.0% and a heat input of 600J per cycle. The correct calculation reveals that the heat output (Qc) is 450J, while the heat input from the high-temperature reservoir (Qh) is determined to be 800J. The confusion arose from mixing up the input and output heats, leading to the incorrect assertion that Qc could be 800J. The established formula E=(Qh-Qc)/Qh confirms that Qh is indeed 800J.

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A heat engine has an efficiency of 25.0% and its heat input is 600J per cycle from the high-temperature reservoir. What is the rate of heat output to the low-temperature reservoir per cycle?

E=(Qh-Qc)/Qh

.25=(600J-Qc)/600J
Qc=450J

book has the answer as 800J.
How are they getting 800J and not 450J?
 
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Originally posted by fish
book has the answer as 800J.
How are they getting 800J and not 450J?
The book's answer makes no sense. Your reasoning is correct. Are you sure you're not mixing up input and output heats? That would explain the book's answer.
 
yes, your're right. It looks like I mixed up input and output heats.
Qc=600J (heat flow into cold res.)

find heat output from high-temp res. which would be
Qh, so solving for Qh you get 800J
 

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