Given:

Two plates of a parallel plate capacitor with equal charge.

Here, both the plates are given same charge +Q.

Consider q charge on face II so that induced charge on face III is -q

Assume a rectangular Gaussian surface ABCD having area, A as shown in the above fig.

Thus, Electric field at point P due to face I E₁=

Electric field at point P due to face II E₂=

Electric field at point P due to face III E₃=

Electric field at point P due to face IV E₄=

negative sign because electric field due to face IV is in leftwards direction).

Since , point P lies inside the conductor thee total electric field at P must be zero

∴ E₁+E₂+E₃+E₄=0

⇒=0

∴ q=0

Therefore zero charge appears on face II and III and Q charge appears on face I and IV

Potential difference b/w the plates is given by

∴ V=0 both the plates are at same potential since both are given equal charges)

1)Potential difference between the plates=0.

2)Charges on outer faces of plates=+Q.

3)Charges on inner faces of plates=0.