A solid cylinder of radius R and length L carries a uniform charge density between r 0 and r R s and an equal charge density of opposite sign, , between r Rs and r R What must be the radius R s so that on rotation of the cylinder about its axis the magnetic moment is zero ...

For the solid cylinder of radius R s Q R s 2 L And L I ...

A solid cylinder of radius R and length L carries a uniform charge density + between r

Question:

A solid cylinder of radius R and length L carries a uniform charge density +ρ between r = 0 and r = R_s and an equal charge density of opposite sign, –ρ, between r = Rs and r = R. What must be the radius R_s so that on rotation of the cylinder about its axis the magnetic moment is zero?