Question

Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude `17.0xx10^(-22) C//m^(2)`. What is E : between the plates?

Answer 1

Given `sigma_(A)=127.0xx10^(-22) C//m^(2)`
`sigma_(B)=17.0xx10^(-22) C//m^(2)`
There are 3 regions
(1) Region (I) is the outer region of first plate
(2) Region (II) is the region between the plates.
(3) region (III) is the outer region of the second plate.

`E_(II)=E_(A)+E_(B)=sigma/(2epsi_(0))+sigma/(2epsi_(0))=sigma/epsi_(0)=(sigma_(A) or sigma_(A))/epsi_(0)`
`=(17.0xx10^(-22))/(8.854xx10^(-22))`
`:. E_(II)=1.92xx10^(-10) N//C`