Two large this metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and magnitude `17.0xx10^(-22) C//m^(2)`. What is `vec(E)` : (a) In the outer region of the first plate. (b) In the outer region of the secound plate, and (c) Between the plates ? See Fig.

Explanation

The situation is represented in the following figure.

A and B are two parallel plates close to each other. Outer region of plate A is labelled as I, outer region of plate B is labelled as III, and the region between the plates, A and B, is labelled as II.
Charge density of plate A, `sigma=17.0xx10^(-22)C//m^(2)`
Charge density of plate B, `sigma=-17.0xx10^(-22)C//m^(2)`
In the regions, I and III, electric field E is zero. This is because charge is not enclosed by the respective plates.
Electric field E in region II is given by the relation,
`E=(sigma)/(in_(0))`
Where,
`in_(0)` = Permittivity of free space = `8.854xx10^(-12)N^(-1)C^(2)m^(-2)`
`thereforeE=(17.0xx10^(-22))/(8.854xx10^(-12))`
`=1.92xx10^(-10)N//C`
Therefore, electric field between the plates is `1.92xx10^(-10)N//C`.