Given, heat absorbed and work done by two systems be Q1,Q2 and W1,W2 and as we know that, By using Ist law of thermodynamics, ΔQ=ΔU+ΔW ⇒ΔU=ΔQ−ΔW where, ΔQ is heat change, ΔU is internal energy change i.e. state function and ΔW is work done. ∴ΔQ1−ΔW1=ΔQ2−ΔW2 or Q1−W1=Q1−W2
