I’ve seen many books considering reversible isochoric processes performed by an ideal gas. But is that possible?
Suppose I’ve a general isochoric process going from A to B, suppose I’m having a decrease of internal energy so that $$\Delta U = Q < 0$$, so I’m letting $Q$ get out of my system, now let’s take this process in the opposite direction, I’m having that heat spontaneously flow from the sorroundings to my system , against the second law . This works also if the process is quasi-static. Can someone show me an example of an isochoric process that can be reversed?