For process 1, \(\Delta U\) is positive, for process 2, \(\Delta U\) is zero and for process 3, \(\Delta U\) is negative. Find the parameters indicating x and y axes.

Volume and Pressure

For process 2, \(\Delta U\) = 0. It will be isothermal process.

In option (1) and (2), temperature is indicated on x-axis. If temperature is shown on x-axis, isothermal process cannot be shown as otherwise shown in the question for process 2. Hence, options (1) and (2) are not correct.

Obviously, option (3) is not correct.