Question

Assume that charge −q is placed on the top plate, and +q is placed on the bottom plate. What is the magnitude of the electric field E between the plates? Express E in terms of q and other quantities given in the introduction, in addition to ϵ0 and any other constants needed..

Answer 1

Answer:

 $E=\frac{q}{\epsilon_oA}$  

Explanation:

Let the area of each plate be A.

From Gauss Law,

$\phi=\frac{q}{\epsilon_o}$

$\phi=E.A$

$\Rightarrow E.A=\frac{q}{\epsilon_o}\\\Rightarrow E=\frac{q}{\epsilon_oA}$

Thus, using Gauss law, electric field between the plates is:

$E=\frac{q}{\epsilon_oA}$