Electric Field outside a Coaxial Cable

[calcuseless]

Homework Statement

Consider an 8mm diameter coaxial cable, which consists of a central conducting wire, and an outer cylindrical conducting braid. If a charge of +30mC is placed on the inner conductor, and a charge of -30mC is placed on the outer conducting braid, what will the electric field, in N/C, be 4cm from the center of the cable?

Homework Equations

Gauss' Law

The Attempt at a Solution

I'm thinking it would be 0 but I don't know how to go about showing this.

 

[WhoWee]

Please show how you reached this conclusion.

 

[calcuseless]

Please show how you reached this conclusion.

...but I don't know how to go about showing this.

welp