If the magnetic dipole moment of an atom of diamagnetic material , paramagnetic material and ferromagnetic amterial are denote by `mu_(d),mu_(p) and mu_(f)` respectively, then:
(a) `mu_(p)=0 and mu_(f) ne0`
(b) `mu_(d)=0 and mu_(p) ne0`
(c) `mu_(d)ne0 and mu_(p) =0`
(d) `mu_(d)ne0 and mu_(p) =0`

Explanation

(b) The individual atoms or ions or molecules of a fiamagnetic material do not possessa permanent diplole moment , hence `mu_(d)=0`
But the atoms ions or molecules of both paramagnetic and ferromagnetic material possess individual magnetic dipole moments hence ` mu_(p) ne0 and mu_(f) ne0`.
(b) is correct.