Dear student,
Non-polar Dielectrics or Molecules. If the centre of gravity of positive charges coincides with the centre of gravity of negative charges then the dielectric is called non-polar dielectric. Thus, a non-polar dielectric has a zero electric dipole moment In the presence of electric field, the charge centres get displaced and dielectric or molecule is then said to be polarized and therefore dielectric acquire an induced dipole moment in the direction of the field.
Diamagnetic materials are slightly repelled by a magnetic field and the material does not retain the magnetic properties when the external field is removed. In diamagnetic materials all the electron are paired so there is no permanent net magnetic moment per atom. Diamagnetic properties arise from the realignment of the electron paths under the influence of an external magnetic field. Most elements in the periodic table, including copper, silver, and gold, are diamagnetic.
As both of them acquire magnetic moment in the presence of magnetic field their properties can be compared.
Regards