Question

Magnetic meridian is a plane
A. Perpendicular to magnetic axis of Earth
B. Passing through the magnetic axis of Earth
C. Perpendicular to geographic axis of Earth
D. Passing through the geographic axis

Answer 1

Recall the basics of the term magnetic meridian. Check the position of the plane of the magnetic meridian according to the geographic or magnetic poles of the Earth and determine which of the given options correctly explains the position of the magnetic meridian of the Earth.

Complete step by step answer:
The planes perpendicular to the magnetic axis of the Earth, perpendicular to the geographic axis of the Earth or passing through the geographic axis are not called magnetic meridian.
Hence, the options A, C and D are incorrect.
The magnetic meridian is an imaginary line on the surface of the Earth which is along the horizontal component of magnetic force on the Earth and joining magnetic North Pole and magnetic South Pole of the Earth.
Therefore, the magnetic meridian is a plane passing through the magnetic axis of the Earth.

So, the correct answer is “Option B”.

Additional Information:
The needle of the magnetic compass always remains parallel to the magnetic meridian of the Earth but not in a steady state.
The imaginary line joining geographic North and South Poles of the Earth is called the prime or true meridian of the Earth.
The angle made by the magnetic meridian with the true meridian is called magnetic declination.

Note:
The students should keep in mind that the plane passing through the magnetic axis and not the geographic axis of the Earth is magnetic meridian because the magnetic poles of the Earth are opposite to that of the geographic poles of the Earth (magnetic North Pole is geographic South Pole and magnetic South Pole is geographic North Pole).