Answer –

Horizontal component of earth’s magnetic field is given by B_H = 0.35 G

Angle made by the needle with the horizontal plane is known as the Angle of dip, given by δ=22°

Earth’s magnetic field strength is given by B

We can relate B and B_H in following manner –

${{B}_{H}}=B\cos \delta $

Rearranging the above relation, we get –

$B=\frac{{{B}_{H}}}{\cos \delta }=\frac{0.35}{\cos {{22}^{\circ }}}$$$

$B=0.38G$

Hence, 0.38 G is the strength of the earth’s magnetic field at the given location.