tangent laws of magnetism
The law states that, if a magnetic field 'B' is applied at right angles to the horizontal
component of the earth's field BH , the needle comes to equilibrium at an angle `theta`
to the magnetic meridian such that,
tan`theta` = `(B)/(Bh)` .
The tangent law is used for comparing the magnetic fields which are mutually perpendicular
andhence to compare the magnetic moments of two bar magnets using Deflection Magnetometer.