1. The problem statement, all variables and given/known data In an infinitely large evenly charged dielectric cylinder(charge density is [itex]\rho[/itex] ) 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] Uploaded with ImageShack.us 2. Relevant equations 3. The attempt at a solution I don't think i can use Gauss law here. Any ideas ?