Hello, This query isn't concerned with solving a problem, but only with details appendant to the problem. The question is as follows: A uniformly charged ring of radius 10.0 cm has a total charge of 64.0 µC. Find the electric field on the axis of the ring at the following distances from the center of the ring. (a) 1.00 cm (b) 5.00 cm (c) 30.0 cm (d) 100 cm A commentary on the problem says that, if you were to place a charged particle in the center of this ring, the force due to the electric fields at that point would be zero. My question is, is the force zero because the electric fields can't point radially towards the center because they could cross? My next question would then be, why can't electric field lines cross?