At a certain location in Africa, a compass `12^@` west of the geographic north. The northe tip of the magnetic needle of a dip circle in the plane of magnetic meridian points `60^@` above the horizontal . The horizontal component of the earth's field measured to be 0.16 G. Specify the direction and magnitude of the earth's field at the location.

Explanation

`phi=12^@, theta=60^@,H_E=0.16G`
`:.H_E=B_Ecostheta," ":.B_E=H_E/(costheta)=(0.16)/(cos60^@)=(0.16)/(1//2)=0.32G`
The tota magnetic field at the place is inclined at `12^@` towards west from geographic north.