1. The problem statement, all variables and given/known data Hi, Having some trouble with answering this question: A thin nonconducting rod with a uniform distribution of +'ve charge 'Q' is bent into a circle of radius R. There is an axis, 'z' which originates in the center of this ring. In terms of 'R', at what +'ve value of z is that magnitude maximum? I'm not precisely sure what this question is asking (slightly ambiguous), however i'm assuming it's asking where the electric field due to this ring is at a maximum. Any help is appreciated! 2. Relevant equations E = (q*z*K)/(Z^2 + R^2)^(3/2) E = F/Q Where K = 1/(4*Pi*E(naught)) 3. The attempt at a solution I have determined z in terms of R to be z = R/Tan(Pi/2 - Theta) Where 'Theta is the angle of elevation between the 'point' on z and the edge of the ring. Thanks!