JEE Physics · Hard

Electrostatics: Multipole Expansion MCQ

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Multipole ExpansionHardQuestion 31486

Question

At large distances, the dominant term in the potential of an arbitrary charge distribution is (if total charge ≠ 0):
  1. A
    Dipole term (∝ 1/r²)
  2. B
    Monopole term (∝ 1/r)
    Correct
  3. C
    Quadrupole term (∝ 1/r³)
  4. D
    Octopole term

Correct answer

Monopole term (∝ 1/r)

Explanation

Multipole expansion: V = V_mono + V_dipole + V_quadrupole +... If total charge Q ≠ 0, monopole term kQ/r dominates at large r. If Q = 0, dipole term dominates.