NTA Abhyas JEE Main2020PhysicsThermodynamicsPractice
An ideal gas is taken through the cycle A → B → C → A , as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J , the work done by the gas in the process C → A is
Options
- A− 5 J
- B− 10  J
- C− 15  J
- D− 20  J
Correct answer
A. − 5 J
Step-by-step solution
Δ W AB = p Δ V = 1 0 2 - 1 = 10 J Δ W BC = 0                 as V = constant From first law of thermodynamics,            Δ Q = Δ W + Δ U Δ U = 0         Process ABCA is cyclic, ∴   Δ Q = Δ W AB + Δ W BC + Δ W CA ∴   Δ W CA = Δ Q - Δ W AB - Δ W BC = 5 - 1 0 - 0 = - 5 J