Three moles of an ideal monoatomic gas perform a cycle shown in figure. The gas temperatures in different states are : T1 = 400 K, T2 = 800 K, T3 = 2400 K, and T4 = 1200 K. The work done by the gas during the cycle is : 

20 kJ

\(Process_{1 \rightarrow 2}\) and \(Process_{3 \rightarrow 4}\) are isochoric process

W₁₂ = 0 ; W₃₄ = 0

W₂₃ = n R (T₃ - T₂) = 3 R (2400-800) = 4800 R

W₄₁ = n R (T₁ - T₄) = 3 R (400-1200) = -2400 R

W = (4800-2400) R = 2400 R = 20 kJ