Question

The horizontal and the vertical components of the earth’s magnetic field at any place are equal. The angle of dip at that place will be:
A. $0^\circ $
B. $45^\circ $
C. $60^\circ $
D. $90^\circ $

Answer 1

Hint: You can start by explaining why the earth has a magnetic field all around it. Then explain what angle of dip is and also write the equation of angle of dip, i.e. $\tan \theta = \dfrac{{{B_V}}}{{{B_H}}}$ . then calculate the value of $\theta $ .

Complete answer:
The angle of dip - This magnetic field at any place can be divided into horizontal ( ${B_H}$ ) and vertical ( ${B_V}$ ) components. The angle of dip is the angle between the horizontal and vertical components of the earth’s magnetic field at any place.

The angle of dip is shown in the following diagram

So, $\tan \theta = \dfrac{{{B_V}}}{{{B_H}}}$
In the problem, we are given that the horizontal and vertical components of the earth’s magnetic field are equal ( ${B_V} = {B_H}$ ).
So, $\tan \theta = \dfrac{{{B_V}}}{{{B_H}}} = 1$
$\tan \theta = {\tan ^{ - 1}}\left( 1 \right)$
$\theta = 45^\circ $
Hence, the angle of dip at a place where the horizontal and vertical components of the earth’s magnetic field are equal ( ${B_V} = {B_H}$ ) is $45^\circ $ .

So, the correct answer is “Option B”.

Additional Information:
Earth has a molten core that contains metals, the material in the molten core moves with the rotation of the earth. Now we know that the earth’s core is made up of molten metals that are in constant motion. We also know that molten metal has free electrons, so the earth’s core has free electrons and they are in motion. We also know that electrons in motion produce a magnetic field all around the earth.

Note:
You can also detect the presence of the earth’s magnetic field by using a compass or by suspending a magnet with a thread. The needle of the compass will align itself with the earth’s magnetic field and the suspended magnet will also do the same, the south pole of the magnet will point towards the magnetic north of the earth and the north of the magnet will point towards the magnetic south of the earth.