Potential difference between 2 and 3 is V. ∴ Charge on capacitor formed by plates 2 and 3 is Q = CV =
ε0A
2d
V Capacity of capacitor between 4 and 5 is C =
ε0A
d
∴ change on plate 5 is Q =
ε0A
d
V Between 2 and 3 battery of V volts is connected. ∴ Potential difference between 2 and 3 is V. Plates 2 and 5 are connected to same terminal of battery, so potential differencebetween them is zero