Physics · Magnetostatics

A circular ring of radius R with total charge Qring has a uniform linear charge density. It rotates about an axis passing through its centre and perpendicular to its plane with a constant angular speed ω. The magnetic field at the centre is found to be B0. Another thin circular disk of the same radius R has a constant surface charge density with a total charge Qdisk. This disk also rotates about the same axis as the ring with the same constant angular speed ω. If the magnetic field at the centre in this case is found to be 10-3B0, what is the value of the ratio Qring/Qdisk?