Question

The magnetic moment of an atom is the result of

• A. A change in the orbital motion of the electrons caused by an applied magnetic field
• B. Electron spin
• C. Both (A) and (B)
• D. None of the option

Answer 1

The correct option is C

Both (A) and (B)

Explanation for correct option:

1. All matter consists ultimately of atoms and in each atom electrons revolve around the atomic nucleus and also spin about their own axes.
2. These motions are associated with magnetic dipole moments and the atoms interact with external fields via these moments.
3. Total magnetic dipole moments of an atom are given by the vector sum of the orbital and spin magnetic moments of all electrons within the atom.
4. Thus, the atoms may or may not have an intrinsic dipole moment,
5. There may or may not have strong interaction among these dipoles.
6. These different materials will behave differently in the external fields and we can classify magnetic materials as diamagnetic, paramagnetic, and ferromagnetic.
7. Therefore, the magnetic moment of an atom is the result of a change in the orbital motion of the electrons caused by an applied magnetic field.
8. Therefore, the magnetic moment of an atom is the result of the electron spin.
9. Hence, both (a) and (b) are the correct options.

Therefore, the correct answer is option (C).