The figure below shows two concentric rings, of radii R and R' = 3R, that lie on the same plane. Point P lies on the central r-axis, at distance D = 2R from the center of the rings. The smaller ring has uniformly distributed charge +Q. In terms of +Q, what is the uniformly distributed charge on the larger ring if the net electric field at P is zero? (modified from Halliday et al., 2015, Chapter 22, Problem 30). y P R' D

The figure below shows two concentric rings, of radii R and R' = 3R, that lie on the same plane. Point P lies on the central r-axis, at distance D = 2R from the center of the rings. The smaller ring has uniformly distributed charge +Q. In terms of +Q, what is the uniformly distributed charge on the larger ring if the net electric field at P is zero? (modified from Halliday et al., 2015, Chapter 22, Problem 30). y P R' D