Question

The permanent magnetic moment of the atoms of a material is zero. The material
(a) must be paramagnetic
(b) must be diamagnetic
(c) must be ferromagnetic
(d) may be paramagnetic

Answer 1

(b) must be diamagnetic

Paramagnetic and ferromagnetic materials have non zero permanent magnetic moment on their own. Only atoms of diamagnetic materials have zero permanent magnetic moment. Hence, (b) is correct.