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42 votes
42 votes
A heat engine that rejects waste heat to a sink at 510 R has a thermal efficiency of 25 percent and a second-law efficiency of 50 percent. Determine the temperature of the source that supplies heat to this engine.

User Dalibor Frivaldsky
by
2.7k points

1 Answer

15 votes
15 votes

Answer:

The correct answer is "1020 K".

Step-by-step explanation:

The given values:


n_(th) = 0,25


n_2=0.50

Now,


n_(th)(rev) = (n_(th))/(n_2)

By putting the values, we get


=(0.25)/(0.50)


=0.50

As we know,


n_(th) (rev)=1-(TL)/(TH)

or,


TH=(TL)/(1-n_(th) (rev))


=(510)/(1-0.50)


=(510)/(0.5)


=1020 \ K

User Stephan Schinkel
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2.9k points