Question

One mole of a monatomic ideal gas undergoes a cyclic process as shown in the figure (where $V$ is the volume and $T$ is the temperature). Which of the statements below is (are) true?

• A. Process I is an isochoric process
• B. In process II, gas absorbs heat
• C. In process IV, gas releases heat
• D. Processes I and II are not isobaric

Answer 1

Answer: (B), (C), (D)

The correct options are
B In process II, gas absorbs heat
C In process IV, gas releases heat
D Processes I and II are not isobaric

(A) Process-I is not isochoric, as we can see that $V$ is decreasing.

(B) Process-II is isothermal expansion
$\Rightarrow$ $\Delta U=0$ but $W>0$ as volume is increasing
$\Rightarrow$ $\Delta Q>0$
(C) Process-IV is isothermal compression,
$\Rightarrow$ $\Delta U=0$ but $W<0$as volume is decreasing
$\Rightarrow$ $\Delta Q<0$
(D) Process-I and III are NOT isobaric because in isobaric process $T\propto V$ hence isobaric $T-V$ graph will be linear.