Kinetic Theory Of Gases Question 7
Question: A thermodynamic process is shown in figure. The pressures and volumes corresponding to some points in the figure are: $ P _{A}=3\times 10^{4}Pa,P _{B}=8\times 10^{4}Pa $ $ and,V _{A}=2\times {{10}^{-3}}m^{3},,V _{D}=5\times {{10}^{-3}}m $ In process $ AB $ , 600 J of heat is added to the system and in process $ BC $ , 200 J of heat is added to the system. The change in internal energy of the system in process AC would be
Options:
A) 560 J
B) 800 J
C) 600 J
D) 640 J
Show Answer
Answer:
Correct Answer: A
Solution:
[a] By the graph, $ W _{AB}=0 $ and $ W _{BC}=8\times 10^{4}[5-2]\times {{10}^{-3}}=240J $
$ \
Therefore W _{AC}=W _{AB}+W _{BC}=0+240=240J $ Now, $ Q _{AC}=Q _{AB}+Q _{BC}=600+200=800J $ From the first law of thermodynamics, $ Q _{AC}=\Delta U _{AC}+W _{AC} $
$ \Rightarrow 800=\Delta U _{AC}+240 $ or $ \Delta U _{AC}=560J $
BETA
