An isothermal process is a constant temperature process. Any heat flow into or out of the system must be slow enough to maintain thermal equilibrium
For ideal gases, if ΔT is zero, ΔU = 0
Therefore, Q = W
Any energy entering the system (Q) must leave as work (W)
P,V may change but temperature is constant
- The cylinder must have conducting walls
- It must happen very slowly so that heat produced during compression is absorbed by surroundings and heat lost during compression is supplied by surroundings.