Recent content by not_waving

Okay I figured I messed up my integration limits, they should be 0 and pi. Though, I still don't get the desired result.

I'm supposed to derive both cases. I'd edit my first post to match the template but I don't know where's the edit button so my attempt at a solution is the second post.

Okay, so firstly i know the electric field of a ring anywhere on the z axis (1). I divide the sphere into infinitesimal rings, each occupying dtheta of the sphere, to get (2). Plugging in into electric field equation and integrating I get zero, which is true but only inside the sphere. However...

My first homework for electrostatics course I'm taking is to find the vector of electric field of a completely hollow sphere (radius r, surface charge density σ in a point A, by integrating the electric field through the whole sphere. I already figured out the electric field of a ring in a point...