Thermodynamics Question 226
Question: In a given process on an ideal gas, $ dW=0 $ and $ dQ<0. $ Then for the gas
Options:
A) the temperature will decrease
B) the volume will increase
C) the pressure will remain constant
D) the temperature will increase
Show Answer
Answer:
Correct Answer: A
Solution:
[a] From the first law of thermodynamics
$ dQ=dU+dW $ Here $ dW=0 $ (given) $ \therefore ~dQ=dU $
Now since $ dQ<0 $ (given)
$ \therefore dQ $ is negative
$ \Rightarrow dU=-ve\Rightarrow dU\text{ decreases}\text{.} $
$ \Rightarrow $ Temperature decreases.
