A regular -gon of circumradius R carries identical point charges +Q at every vertex…
PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A regular n-gon of circumradius R carries identical point charges +Q at every vertex except the vertex P under consideration. Determine the electric field at P due to the charges on the remaining (n−1) vertices.
(a) Derive a general expression for the magnitude and direction of this field in terms of n, Q, and R.
(b) Evaluate your expression for a square of side 0.30 m with Q=4μC at the other three vertices. (Take k=9.0×109Nm2C−2.)
(c) Discuss qualitatively how the field at P changes as n becomes very large while R is kept constant.