Question

Refer to figure. Let ∆U₁ and ∆U₂ be the changes in internal energy of the system in the process A and B. Then
(a) ∆U₁ > ∆U₂
(b) ∆U₁ = ∆U₂
(c) ∆U₁ < ∆U₂
(d) ∆U₁ ≠ ∆U₂.

Answer 1

(b) ∆U₁ = ∆U₂

​The internal energy of the system is a state function, i.e. it only depends on the initial and final point of the process and doesn't depend on the path followed. Both processes A and B have common initial and final points. Therefore, change in internal energy in process A is equal to the change in internal energy in process​ B. Thus,
∆U₁ = ∆U₂ = 0