MCQ
A frictionless heat engine can be $100 \%$ efficient only if its exhaust temperature is ............
- AEqual to its input temperature
- BLess than its input temperature
- ✓$0 \,K$
- D$0^{\circ} C$
✓
Answer
Correct option: C.
$0 \,K$
c
(c)
(c)
$\because \eta=1-\frac{T_2}{T_1}$
If exhaust temperature zero kelvin then $\eta=100 \%$.
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