Answer :
Earth’s magnetic field at the given place is given by H = 0.36 G
The magnetic field at distance d from the axis of the magnet can be calculated using the following formula –
${{B}_{1}}=\frac{{{\mu }_{0}}2M}{4\pi {{d}^{3}}}=H$
Where \[{{\mu }_{0}}=4\pi \times {{10}^{-7}}Tm{{A}^{-1}}\]
The magnetic field on the equatorial line of the magnet at the same distance d, is given as:
${{B}_{2}}=\frac{{{\mu }_{0}}M}{4\pi {{d}^{3}}}=\frac{H}{2}$
Using the relation of B1, we get –
Total magnetic field is given by – B = B1 + B2, therefore –
$B=H+\frac{H}{2}=0.36+0.18$ Hence, 0.54 G is the magnetic field in the direction of earth’s magnetic field.