How Is Surface Charge Density Calculated from Electric Field Magnitude?

[pat666]

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?
Express your answer with the appropriate unit

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

 

[aim1732]

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.

 

[pat666]

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

 

[aim1732]

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.