If r be the distance of a point on the axis of a magnetic dipole from its centre then the magnetic field at such a point is proportional to

Options

(a) 1/r
(b) 1/r²
(c) 1/r³
(d) none of these

Correct Answer:

1/r³

Explanation:

As we know that, the magnetic field at a point due to the dipole is given by B = (μ₀ / 4π) × (M / r³) × √(1 + 3 cos² θ) where, M is magnetic dipole moment. Then, B ∝ 1 / r³