Solution: Solution: In the P-T image, the isovolumic line is an inclined straight line passing through the origin, and the isovolumic lines of I and II states are shown in the following figure:

According to the ideal gas state equation: PVT = K.

When the gas temperature is T 1, as can be seen from the above figure, P 1 > P2, so V 1 < V2.

According to the gas equation: p1v1t1= p2v2t2.

According to the topic, the pressure is inversely proportional to the thermodynamic temperature, that is, p 1p2=T2T 1.

The above two formulas are expressed simultaneously: V2 = T22 1V 1.

So choose: D.