If anyone can help with this problem it would be greatly appreciated. I think I know what I'm doing, but am not sure of a couple things.
An isolated spherical capacitor has charge +Q on its inner conductor of radius r1 and charge -Q on its outer conductor of radius r2. half of the volume...
With your question about why there are no s-d transitions it is because of the need to conserve total angular momentum. In a transition the difference between the angular momentum of the two states must differ by exactly one unit as the photon will also have one unit of angular momentum.
Not...