Thank you, tiny-tim.
I think it could be inward because the situation is not top-down symmetric. Since we have a positive charge on top the field tend to diverge outward in the +z direction. But the by "the symmetry of the Coulomb force law" (I don't know how to say it better), the field will...
Homework Statement
It's example 3.8 in the Griffiths book in case someone has it. Basically the problem involves a uncharged metal sphere in a uniform field in the +z direction. Naturally, there will be induced positive charges on top and negative charges at the bottom. The question asks for...