Hi, this concerns thermodymanics. A block of volume V is reversibly compressed from pressure P1 to pressure P2 isothermally at temperature T. It goes on to ask about the heat expelled, but that's not my question. It is a solid, obviously not an ideal gas, so I'm sure the internal energy can change, yes? Also, what information can we deduce from the fact that it's a reversible process, if any? Thanks.