Thermodynamics - Result Question 30
31. A sample of gas expands from volume $V_1$ to $V_2$. The amount of work done by the gas is greatest, when the expansion is
(a) adiabatic
(b) isobaric
(c) isothermal
(d) equal in all cases
[1997]
Show Answer
Answer:
Correct Answer: 31. (b)
Solution:
- (b) In thermodynamics for same change in volume, the work done is maximum in isobaric process because in $P-V$ graph, area enclosed by curve and volumeaxis is maximum in isobaric process.
(d) We know that in adiabatic process, $P V^{\gamma}=$ constant
From ideal gas equation, we know that $P V=n R T$
$V=\frac{n R T}{P}$
Puttingt the value from equation (2) in equation (1),
$P(\frac{n R T}{P})^{\gamma}=$ constant $P^{(1-\gamma)} T^{\gamma}=$ constant
