1. The problem statement, all variables and given/known data In what direction (using cylindrical coordinates) around a uniformly disk does the electric field NOT point? 2. Relevant equations The directions could be r, θ, or z. 3. The attempt at a solution I don't think it can point in the θ or the z direction-- either one would imply that there is a built-in preference to space for a certain direction, because symmetry arguments say that these two directions should be treated equally in all directions. I'm not sure though-- I'm assuming they mean around the edge of the disk on the outside, is this correct?