Question

If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material is denoted by $\mu _{d}, \, \mu _{p}$ and $\mu _{f}$ respectively, then

• A. $\mu _{d}=0 $ and $ \mu _{p}\neq 0$
• B. $\mu _{d} \, \neq 0 $ and $ \mu _{p}=0$
• C. $\mu _{p}=0 $ and $ \mu _{f}\neq 0$
• D. $\mu _{d}\neq$ and $ \mu _{f}\neq 0$

Answer 1

Answer: (A)

The magnetic dipole moment of a diamagnetic material is zero as each of its pair of electrons has opposite spins, i.e., $\mu _{d}=0.$ Paramagnetic substances have dipole moment > 0, i.e., $\mu _{p} \, \neq 0$ , because of the excess of electrons in its molecules spinning in the same direction.
Ferromagnetic substances are very strong magnets and they also have a permanent magnetic moment, i.e., $\mu _{f}\neq 0.$