A solid sphere of radius R carries a uniform charge density, +0, between r = 0 and

A solid sphere of radius R carries a uniform charge density, +ρ0, between r = 0 and r = Rs and an equal charge density of opposite sign, –ρ0, between r = Rs and r = R. The sphere rotates about its diameter with angular velocity ω. Find Rs such that magnetic moment of the sphere is zero. What is the net charge carried by the sphere?