According to first law of thermodynamics, δQ=δU+δW Along the path adc Change in internal energy, δU1=δQ1−δW1=50J−20J=30J Along the path abc, Change in internal energy, δU2=δQ2−δW2; δU2=36J−δW2 As change in internal energy is path independent. ∴δU1=δU2 ⇒30J=36J−δW2 δW2=36J−30J=6J