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11.Thermodynamics
normal
Choose the incorrect statement from the following
$S1$: The efficiency of a heat engine can be $1$, but the coefficient of performance of a refrigerator can never be infinity
$S2$: The first law of thermodynamics is basically the principle of conservation of energy
$S3$: The second law of thermodynamics does not allow several phenomena consistent with the first law
$S4$: A process, whose sole result is the transfer of heat from a colder to a hotter object is impossible
A
$S1$
B
$S2$
C
$S3$
D
$S4$
Solution
Efficiency of heat engine, $\eta = 1 – \frac{{{T_2}}}{{{T_1}}}$ For $\eta = 1$ (i.e. $100\%$) either, $\eta = 1$ or $T_2\, = 0\,K$ As source at infinite temperature or sink at $0\,K$ are not attainable, therefore heat engine cannot have efficiency $1$.
Standard 11
Physics
