# Surface charge density

## Homework Statement

A large plane having uniform charge density has an electric field just outside the plane that points directly toward the plane with magnitude 1.50×10^4 N/C .

What is the surface charge density?

## Homework Equations

I am not sure how to start this, the relevant equations would probably be enough to get me through this questions.

## The Attempt at a Solution

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Right. By Gauss Law electric field of an infinitely large plane non-conducting sheet is σ/2ε where σ is charge density and ε is permittivity of free space.

thanks for that, what is the permittivity of free space????? also is this meant to be an easy question?

Permittivity constant accounts the dielectric properties of the medium and for air(or vacuum) it is 8.854×10−12 Fm-1.
Remember the constant in the Coulomb's Law? It is actually 1/4πε .
As for the question itself if you are familiar with Gauss law it shouldn't be difficult and the result is used as a standard formula in many texts.