Points $A$ and $B$ are situated perpendicular to the axis of a small bar magnet at large distances $x$ and $3 x$ from its centre on opposite sides. The ratio of the magnetic fields at $A$ and $B$ will be approximately equal to

Define pole strength of magnet. and Write the unit of pole strength of magnet
 

Two magnets $A$ and $B $ are identical and these are arranged as shown in the figure. Their length is negligible in comparison to the separation between them. A magnetic needle is placed between the magnets at point $P$ which gets deflected through an angle $\theta $ under the influence of magnets. The ratio of distance ${d_1}$ and ${d_2}$ will be

A permanent magnet

The magnetic field to a small magnetic dipole of magnetic moment $M$, at distance $ r$  from the centre on the equatorial line is given by (in $M.K.S. $ system)