A short magnet of moment $6.75\, Am^2$ produces a neutral point on its axis. If horizontal component of earth's magnetic field is $5 \times {10^{ – 5}}\,Wb/{m^2}$, then the distance of the neutral point should be…..$cm$

Of the following Fig., the lines of magnetic induction due to a magnet $SN$, are given by

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)

Two magnetic dipoles $X$ and $Y$ are placed at a separation $d$, with their axes perpendicular to each other. The dipole moment of $Y$ is twice that of $X$. A particle of charge $q$ is passing through their mid-point $P$, at angle $\theta  = 45^o$ with the horizontal line as shown in the figure. What would be the magnitude of force on the particle at that instant ? ($d$ is much larger than the dimensions of the dipole)

Calculate the axial field of a finite solenoid.