Thermodynamics Ques 39
39. When $1 kg$ of ice at $0^{\circ} C$ melts to water at $0^{\circ} C$, the resulting change in its entropy, taking latent heat of ice to be $80 cal /{ }^{\circ} C$, is
[2011]
(a) $273 cal / K$
(b) $8 \times 104 cal / K$
(c) $80 cal / K$
(d) $293 cal / K$
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Answer:
Correct Answer: 39.(d)
Solution:
- (d) Change in entropy is given by
$\Delta S=\frac{dQ}{T}$ or $\Delta S=\frac{\Delta Q}{T}=\frac{mL_f}{273}$
$\Delta S=\frac{1000 \times 80}{273}=293 cal / K$.
BETA
