CBSE Class 12-science Answered

If a non-magnetic piece of metal like copper is suspended at its center of gravity, the copper plate remains horizontally in equilibrium. If on the other hand, a magnetic needle is suspended at its center of gravity so that it is free to take up any position in the magnetic north-south plane, it makes an angle.

The earth's magnetic field is not parallel to the earth's surface excepting at the magnetic equator. As a result, excepting at the magnetic equator, a freely suspended needle makes an angle with the horizontal.

The angle of dip is different at different places on the surface of the earth. At the magnetic equator it is 0^o and increases and at the magnetic pole it becomes 90^o.