# Electric Field hard question

1. Sep 15, 2008

### 9giddjl

Electric Field hard question :(

1. The problem statement, all variables and given/known data

What is the electric field between two parralel plats, each of area 1 m^2 which are separated by a distance of 0.01 m, if each plate is charged equally but oppositely with a charge of magnitude 8.84 x 10^-8 C?

2. Relevant equations
E= kQ/ d^2

3. The attempt at a solution
i tried to find the electric field at each plat using E= kQ/ d^2. Because it says in the question 'find the electric field between the two parralel plates, does this mean the midpoint?
i dont really get what to do with the area either?
Any Help would be greatly appreciated
THANKYOU :^)

2. Sep 15, 2008

### entorm

Re: Electric Field hard question :(

The electric field between two parallel plates, when their separation is much smaller than their size, is uniform (as long as you stay away from the edges)
and has a magnitude equal to the charge density divided by the permissivity of the medium.

The area is given to you so that you calculate the charge surface density. I think you can find plenty of information on this topic in any good electrostatics textbook.

3. Sep 15, 2008

### Defennder

Re: Electric Field hard question :(

Make use of Gauss law and symmetry here.