Thermodynamics Question 136
Question: If the ratio of specific heat of a gas at constant pressure to that at constant volume is $ \gamma $ , the change in internal energy of a mass of gas, when the volume changes from V to 2V constant pressure p, is
[CBSE PMT 1998]
Options:
A) $ R/(\gamma -1) $
B) $ pV $
C) $ pV/(\gamma -1) $
D) $ \gamma pV/(\gamma -1) $
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Answer:
Correct Answer: C
Solution:
$ \Delta U=\mu C _{V}\Delta T=n( \frac{R}{\gamma -1} )\Delta T $
$ \Rightarrow \Delta U=\frac{P\Delta V}{(\gamma -1)}=\frac{P(2V-V)}{\gamma -1}=\frac{PV}{(\gamma -1)} $
