Question

Four students observed an ideal gas undergoing a change of state from A to B. Their observations are along four different paths shown in the figure below. Their conclusions are as follows:
$\left(P\right)$ Change in internal energy is same in $IV$ and $III$ cases, but not in $I$ and $II$
$\left(Q\right)$ Change in internal energy is same in all the four cases
$\left(R\right)$ Work done is maximum in case $I$
$\left(S\right)$ Workdone is minimum in case $II$
Which option represents correct conclusions drawn by the students?

• A. $P\text{and}R$
• B. $Q\text{and}R$
• C. $P\text{and}S$
• D. $Q\text{and}S$

Answer 1

The correct option is B $Q\text{and}R$


From the figure, we can draw an inference that, as initial and final states of all the process are same, the internal energy is same in all the four cases.
To find the work done, we can measure area under each case. It is evident that area under path $I$ is maximum.
$\therefore$ Work done is maximum in case $I$.