Thermodynamics Question 311
Question: Three moles of an ideal monoatomic gas perform a cycle . The gas temperatures in different states are $ T _{1}=200K,T _{2}=400K,T _{3}=1600K $ and $ T _{4}=800K. $ The work done by the gas during the cycle is (Take $ R=25/3J/mol\text{-}K $ )
Options:
A) 5 kJ
B) 25 kJ
C) 15 kJ
D) 20 kJ
Show Answer
Answer:
Correct Answer: C
Solution:
(c) Process $ l\to 2 $ and Process $ 3\to 4 $ are isochoric processes.
$ W _{12}=0,W _{34}=0,W _{23}=nR(T _{3}-T _{2}) $
$ =3R(1600-400) $
$ W _{41}=nR(T _{1}-T _{4})=3R(200-800)=-1800R $
$ W=(3600-1800)R=1800R=15kJ $
