Question

Define magnetic declination.

Answer 1

Hint: The answer to this question is totally based on our understanding of the magnetism of the earth. If we have a clear concept of the magnetism of the earth, then easily we can define the magnetic declination. Also, we need to know about the magnetic meridian and geographical meridian.

Complete answer:
First of all let us define magnetic meridian.
Magnetic meridian: The imaginary line connecting the magnetic south and north poles is known as magnetic meridian. It can be taken as the horizontal component of magnetic force lines along the surface of the earth.
After this let us define geographical meridian.
Geographical meridian: It is the vertical plane passing through the geographical north and south axis.
Now, we can define magnetic declination.

Magnetic declination: The angle between the magnetic meridian and geographical meridian, at a place is known as magnetic declination at that point. Magnetic declination is also known as magnetic variation.

Note: We should not confuse between magnetic declination and angle of dip. Angle of dip is defined as the angle between the direction of total magnetic field of earth and a horizontal line in magnetic meridian. Angle of dip is also known as magnetic inclination. The magnetic field of earth is also known as the geomagnetic field. The magnetic field of earth is similar to the magnetic field of a bar magnet. The magnetic field of earth is different at different locations.