Question

If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by ${\mu }_d,{\mu }_p$ and ${\mu }_f$ respectively, then :-

Answer 1

In diamagnetic substances in each part pair of electron, The spins of both the electrons are in opposite direction.

Hence the electron of each pair completely cancels , the magnetic moment of each atom of such substance is zero, i.e., ${\mu }_d=0.$



The property of para magnetism is found in those substances whose atoms of molecules have an excess of electron spinning in the same direction.

Hence, atoms of paramagnetic substances have permanent magnetic moment, i.e., ${\mu }_p\ne 0.$

The property of ferromagnetism is found in substance which acquire very strong magnetism when placed in an external magnetic field. Like the paramagnetic substances each atom of ferromagnetic substances also has a permanent magnetic moment.

Hence, option (b) is the correct alternative.