Q.Match the Column-A item 'Intensity of magnetic field on axial position' with the correct entry from Column-B. Column-B options (as printed, unordered): watt; μ₀/4π · 2md/(d² − l²)²; 1/(4πε₀) · 2pr/(r² − l²)²; Transverse wave; A coil.

Modelling a short bar magnet as two poles $\pm q_m$ a distance $2l$ apart (dipole moment $m=q_m(2l)$, from S to N), the field it produces at a point far away ($d\gg l$) along its own AXIS is $B_{\text{axial}}=(\mu_0/4\pi)(2m/d^3)$, directed along $\vec{m}$; on its EQUATORIAL line (the perpendicular bisector of the S-N line) it is $B_{\text{eq}}=(\mu_0/4\pi)(m/d^3)$, directed opposite to $\vec{m}$ and exactly HALF the axial …