CBSE Class 12-science Answered

The Earth's  magnetic field is similar to that of a bar magnet  tilted 11 degrees from the spin axis of the Earth.

Magnetic fields surround electric currents, so we surmise that circulating electic currents in the Earth's molten metalic core are the origin of the magnetic field. A current loop gives a field similar to that of the earth. The magnetic field magnitude measured at the surface of the Earth is about half a Gauss and dips toward the Earth in the northern hemisphere. The magnitude varies over the surface of the Earth in the range 0.3 to 0.6 Gauss.