Thermodynamics Ques 40
40. An engine has an efficiency of $1 / 6$. When the temperature of sink is reduced by $62^{\circ} C$, its efficiency is doubled. Temperature of the source is
[2007]
(a) $37^{\circ} C$
(b) $62^{\circ} C$
(c) $99^{\circ} C$
(d) $124^{\circ} C$
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Answer:
Correct Answer: 40.(c)
Solution:
- (c) Since efficiency of engine is $\eta=1-\frac{T_2}{T_1}$
According to problem,
$\frac{1}{6}=1-\frac{T_2}{T_1}$ $\quad$ …….(1)
When the temperature of the sink is reduced by $62^{\circ} C$, its efficiency is doubled
$2(\frac{1}{6})=1-\frac{T_2-62}{T_1}$ $\quad$ …….(2)
Solving (1) and (2)
$T_2=372 $ $K$
$T_1=99^{\circ} C=$ Temperature of source.
BETA
