# E Field caused by infinite plate

1. Jan 19, 2006

### WarpDrive

What is the equation for the electric field caused by an infinite plate of charge? Is it sigma/2epsilon0?

So does that mean that the distance from a point to the plate doesn't matter in computing the E field? How does this change if a solid conducting slab with significant thickness (2 cm) is used? I know that the charges should build up on each side, with half of the charges on each side, so is that treated then as 2 plate charges?

2. Jan 20, 2006

### Tom Mattson

Staff Emeritus
That's right. An infinite plate of charge has a constant, uniform E field.

See the following website:

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elesht.html

The first segment, entitled Electric Field: Sheet of Charge covers the thin plate, and the second segment, entitled Electric Field: Parallel Plates covers thick plates.