NEET

Magnetic susceptibility (? ) measures in an external magnetic field, how much a material gets magnetized.Paramagnetic materials:? is positive but small.
Diamagnetic materials:? is negative and very small.
Ferromagnetic materials:? is positive and large, often many orders of magnitude greater than 1.

Any bar magnet which is freely suspended aligns itself with the Earth's magnetic field. Earth attract the north pole of the suspended magnet because earth behaves like a giant bar magnet with a magnetic south pole near the geographic North Pole.

The magnetizing force applied to a material is called the Magnetic intensity (H) and the total magnetic effect inside a material is called the magnetic field (B), it includes both the applied magnetic field and the material's response (magnetization).
Following is the formula showing the relation:
B =? (H + M)
Where? is the permeability of free space and M is magnetization.