Magnetism and Matter - Result Question 19

23. 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

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(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) $\mu_d \neq 0$ and $\mu_f \neq 0$

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Answer:

Correct Answer: 23. (a)

Solution:

  1. (a) The magnetic dipole moment of diamagnetic material is zero as each of its pair of electrons have opposite spins, i.e., $\mu_d=0$.

Paramagnetic substances have dipole moment $>0$, i.e. $\mu_p \neq 0$, because of excess of electrons in its molecules spinning in the same direction.

Ferro-magnetic substances are very strong magnets and they also have permanent magnetic moment, i.e. $\mu_p \neq 0$.