Express the current density of a spherical shell of radius a, rotating with angular velocity omega, with surface charge density sigma Delta function will be denoted d(x). Spherical coordinates will be used I have concluded that for a given chunk (if we restrict to the 0<theta<pi/2 domain), the velocity will be given by v=a*Sin(theta)*(omega). It is clear that the current density will only have a phi component. I have concluded: J_phi = (sigma)*a*Sin(theta)*(omega)*d(r'-a) Where the delta function is used to restrict the current density to the sphere's surface. Can anyone confirm that this reasoning is correct?