Question

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.

• A. Temperature and volume
• B. Temperature and pressure
• C. No. of moles and pressure
• D. Volume and pressure

Answer 1

The correct option is D Volume and pressure

$\Delta U=0\Rightarrow \Delta T=0\Rightarrow$ isothermal process
Similarly $\Delta T>0$ for 1 and $<0$ for 3.
Thus starting from same pressure(P) and volume(V) and reaching same final volume the values of pressure will be $P_1>P_2>P_3$
Clearly x, y axes are thus volume and pressure axes respectively.