The correct option (A) [(A∈0V02)/d]
Explanation:
Work done = change in energy
W = (Q2/2C1) – (Q2/2C)
Now C = (A∈0/d) & C1 = (A∈0/d)
i.e. C1 = (C/3)
∴ W = [Q2/(2C/3)] – (Q2/2C) = (2Q2/2C) = (Q2/C)
∴ W = (Q2/C) = [(C2V02)/C] = CV02 --------- Q = CV
∴ W = [(V02A∈0) / d] --------- C = (A∈0/d)