1. The problem statement, all variables and given/known data A very long, solid insulating cylinder with radius R has a cylindrical hole with radius a bored along its entire length. The axis of the hole is a distance b from the axis of the cylinder, where a < b < R. The solid material has a uniform volume charge density, ρ. Find the magnitude and direction of the electric field inside the hole. 2. Relevant equations Gauss' Law 3. The attempt at a solution I don't understand why the electric field inside the hole is 0. I mean there is no charge so therefore there is no net electric field. However this isn't what my book gives as an answer..