parallel plate capacitor

In this class I will discuss problems on parallel plate capaitor from I.E. Irodov and H.C. varma. The questions are mentioned below.

ques-1 Three identical metal plates with large surface areas are kept parallel to each other as shown in figure (30-E8). The leftmost plate is given a charge Q, the rightmost a charge -2Q and the middle one remains neutral. Find the charge appearing on the outer surface of the rightmost plate.

Ques-2 Four large metal plates are located at a small distance d from one another as shown in . The extreme plates are inter- connected by means of a conductor while a potential difference ∆φ is applied to internal plates. Find:

(a) the values of the electric field strength between neighboring  plates;

(b) the total charge per unit area of each plate.

Four identical metal plates are located in air at equal distances d from one another. The area of each plate is equal to S.

Find the capacitance of the system between points A and B if the plates are interconnected as shown