MCQ
An ideal heat engine working between temperature $T_1$ and $T_2 $ has an efficiency $\eta$, the new efficiency if both the source and sink temperature are doubled, will be
- A$\frac{\eta }{2}$
- ✓$\eta $
- C$2\eta $
- D$3\eta $
✓
Answer
Correct option: B.
$\eta $
b
(b) In first case ${\eta _1} = \frac{{{T_1} - {T_2}}}{{{T_1}}}$
In second case ${\eta _2} = \frac{{2{T_1} - 2{T_2}}}{{2{T_1}}}$$ = \frac{{{T_1} - {T_2}}}{{{T_1}}} = \eta $
(b) In first case ${\eta _1} = \frac{{{T_1} - {T_2}}}{{{T_1}}}$
In second case ${\eta _2} = \frac{{2{T_1} - 2{T_2}}}{{2{T_1}}}$$ = \frac{{{T_1} - {T_2}}}{{{T_1}}} = \eta $
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