Homework Help: Infinite cylinder

1. Feb 2, 2012

funoras

1. The problem statement, all variables and given/known data
In an infinitely large evenly charged dielectric cylinder(charge density is $\rho$ ) there is an infinitely large cylindrical void. Prove that the electric field inside the void is homogenous and find its value. (picture)
http://img513.imageshack.us/img513/5747/61734727.png [Broken]

2. Relevant equations

3. The attempt at a solution
I don't think i can use Gauss law here. Any ideas ?

Last edited by a moderator: May 5, 2017
2. Feb 4, 2012

marcusl

You can calculate the field at any point (radius) in a uniformly charged cylinder using Gauss's law. Now add 2 cylinders, one big and one small, of opposite charge densities to create the hole. The field within is the sum of the fields within each cylinder.