Question

At a certain location in Africa, a compass points 12° west of thegeographic north. The north tip of the magnetic needle of a dip circleplaced in the plane of magnetic meridian points 60° above thehorizontal. The horizontal component of the earth’s field is measuredto be 0.16 G. Specify the direction and magnitude of the earth’s field at the location.

Answer 1

Given: The Angle of declination, θ=12°; the angle of dip, δ=60°; the horizontal component of earth’s magnetic field, B H =0.16 G.

The horizontal component of the magnetic field is given as,

B H =Bcosδ B= B H cosδ

By substituting the given value in the above expression, we get,

B= 0.16 cos60° = 0.16 0.5 =0.32 G

Thus, Earth’s magnetic field lies in the vertical plane at 12° west of geographic north, making an angle of 60° with the horizontal with a magnitude of 0.32 G.