- #1

Silviu

- 624

- 11

## Homework Statement

Calculate the surface charge density induced by a point source above an infinite conducting plane, with 0 potential.

## Homework Equations

##E=-\nabla V##

##V=\frac{q}{4\pi \epsilon_0 r}##

## The Attempt at a Solution

I used the method of image charges and I calculated the potential induced by the charge and its mirror image ##V(x,y,z)##. Then I took a box around the plane and I applied the Gauss law. However, In their solution, assuming that the charge is in the ##+z## region and the surface is in the xy plane, they say that the E is 0 in the ##-z## area. From here ##\sigma = \epsilon_0 E = -\epsilon_0 \partial_z V##. I got the same result, but with a factor of 2 difference. My question is, why is the electric field 0 in the ##-z## region?

Thank you!