Hi Everyone! I have couple of questions this time! :D 1) In refrigerator we say that we have to do some work on system to flow heat from lower temp body to higher temp reservoir , so if temp1 > temp2 then temp2 + work = temp1 now what i want to ask is that what kind of work we do on system to absorb heat? e.g we do expansion on system please tell taking example of pistons , it makes me pretty clear! 2) if we say that reversible process why we say that heat should be flown infinety slowly , no dissipation of enerygy etc?? Thanks a lot for taking your preciuos time for me!!!