In this video lecture I have derived the formula to calculate the magnetic susceptibility and tried to give answer on the basis of force that why the level of liquid rises up in the presence of the external magnetic field. When a substance is placed in an external magnetic field, the substance will produce its own magnetic field. If the substance is para magnetic, this field adds to the applied field. If the substance is diamagnetic, this field subtracts from the main field. This contribution to the external magnetic field is known as the magnetic susceptibility of the substance.