Question

The vertical component of the earth's magnetic field is:
A. Zero at the magnetic pole
B. Zero at the geographic pole
C. Same everywhere
D. Zero at the magnetic equator

Answer 1

The angle of dip is the angle between magnetic north and geographic north. The magnetic field at a certain place depends on the angle of dip. The vertical component of the earth’s magnetic field is given as ${B_V} = B\sin \theta$ and that of the horizontal is ${B_H} = B\cos \theta$.

Complete step by step answer:
We know that the earth’s magnetic field has two components: vertical component and horizontal component. The vertical and horizontal component of the earth’s magnetic field are expressed as,
${B_V} = B\sin \theta$ and, ${B_H} = B\cos \theta$
Here, B is the magnitude of the earth’s magnetic field and $\theta$ is the angle of inclination or angle of dip.

At the magnetic equator, the angle of dip is zero. Therefore, the vertical component of the earth’s magnetic field becomes,
${B_V} = B\sin 0$
$\Rightarrow {B_V} = 0$
Therefore, we can say that at the magnetic equator, the vertical component of the earth’s magnetic field is zero.
Also, the horizontal component will be,
${B_H} = B\cos \left( 0 \right)$
$\therefore {B_H} = B$

So the correct answer is option D.

Additional information:
A magnetic equator is defined at the line around the earth where the magnetic field is horizontal or parallel to the earth’s surface. It does not circle the earth as a smooth line like the geographic equator but interact it meanders north and south.

The earth gets its own magnetic field lines because of the presence of the metallic pulls that are present at the outer core as well as in the inner core .The outer core consists of molten iron, while the inner core has the solidified elements.

Note: The earth magnetic poles are not aligned to the actual graphic north and south poles. Instead the magnetic South Pole is coddled while the magnetic north pole lies in Antarctica. The magnetic poles are inclined by about 10 degrees to the earth rotational axis. So, all this time your compass was really pointing to Canada not the true north.