In this topic, you study Magnetic Permeability.
Conceptually, the current is considered to set up a magnetic field strength (H) at a particular point in the surrounding space. The magnetic field strength at any point in the magnetic field is utilized in maintaining the magnetic flux and producing the particular value of flux density (B) at that point. Thus, H is the cause and B is the effect. The flux density at any point is determined not only by the magnetic field strength at that point but also by the magnetic property of the medium known as its permeability.
It may be defined as the ease with which a magnetic flux permeates a medium or in other words, it is the receptiveness of the medium in having flux set up in it
Permeability of Free Space
For a magnetic field in vacuum (or free space), the ratio of flux density (in tesla) to magnetic field strength (in amperes / metre) producing that flux density is called the permeability of free space or magnetic space constant.
- It is the measure of the ease with which a magnetic flux permeates (passes through) a vacuum.
It is experimentally verified that for a magnetic field in a vacuum, flux density Bo is everywhere proportional to H and the ratio Ba/H has a constant value of 4Ttx 10-7 (this is also true for a magnetic field in air or any other non-magnetic material). Thus, at any point in a magnetic field in a vacuum,
or,
Permeability of free space,
tesla
The μo in the above Expression (4.7) is often stated without a unit. Strictly speaking, the unit of is henry per metre (H/m) where henry is the unit of inductance.