Thermodynamics Question 152
Question: An ideal heat engine exhausting heat at $ 77^{o}C $ is to have a 30% efficiency. It must take heat at
[BCECE 2004]
Options:
A) $ 127^{o}C $
B) $ 227^{o}C $
C) $ 327^{o}C $
D) $ 673^{o}C $
Show Answer
Answer:
Correct Answer: B
Solution:
$ \eta =1-\frac{T _{2}}{T _{1}} $
Therefore $ \frac{30}{100}=1-\frac{350}{T _{1}} $
Therefore $ \frac{350}{T _{1}}=1-\frac{50}{100}=\frac{70}{100}=\frac{7}{10} $
Therefore $ T _{1}=500K=227{}^\circ C $
