What is permeability?

The ability of a material to become magnetized is called the magnetic permeability or permeability. An example of this is the rubbing of iron against a Magnetswhereby the iron becomes magnetized and develops its own magnetic field, which means that it has a certain degree of magnetic permeability. Many substances, including water, have some degree of magnetic permeability. When a material is placed in a magnetic field, it interacts with the field in one way or another. The permeability of a substance therefore describes the way in which the material reacts and the effects of the field on the material. A substance with magnetic permeability will magnetize either in the direction of the field or in the opposite direction. Thus, depending on the permeability, the substance will either be attracted or repelled by the field.