## CHAPTER 7

## Magnetic Properties

#### 7.1 Magnetic permeability

Magnetic permeability represents the ease with which a material allows magnetic force of lines to pass through it. The permeability of vacuum or free space is denoted by *μ*_{0} and it is taken as the standard with respect to this the permeability of all materials is expressed. The permeability of the medium of a material is denoted as *μ*; it is the product of the permeability of free space (*μ*_{0}) and relative permer ability (*μ*_{r}).

∴ *μ = μ*_{r} μ_{0} H/M

*μ*_{r} is purely a number; it has no units. The permeability of free space is:

*μ*_{0} = 4*π* × 10^{-7} H/M

Let *B* be the magnetic flux density in a magnetic material by applying magnetic field of intensity *H* and *B*_{0} be the flux density at the same place if the ...