Magnetism & Electromagnetism (part 1)

     Magnetism 

Permeability    

         Magnetism is another impotent lesson joined with Electrical Technology. Magnetism and
Electromagnetism are dependent upon permeability. Permeability is a property that is ability to
support the formation of a magnetic field of the media.

Low of magnetic force

Force between two magnetic poles,

•  directly proportional to their pole strengths
•  inversely proportional to the square of distance between them
• inversely proportional to the permeability of the surround media

                                      -By Coulomb-

m₁, m₂ = Magnetic strengths of two poles
r           = Distance between two poles
µ          = Absolute permeability surrounding area
F          = Force between two magnetic pols

     F = km₁m₂ / µr²   k is a constant
k = 1/4π

therefore 
           F = m₁m₂ / 4πµr²

Magnetic Field Strength(H)

When the N-pole of one Weber placed at the magnetic field acting force of that pole is called
Magnetic Field Strength.Unit of Magnetic Field Strength is Newton per Weber.

            H = m / 4πµr²

 Magnetic Potential (M)

 Work done in shifting a N pole of 1 Weber from infinity at any point in a magnetic field is
Magnetic Potential at that point.

      

            M = m / 4πµr

Flux per Unit pole (Φ)

 A unit N- pole is supposed to radiate out a flux of one Weber.

           

              

            Φ = m Wb

Flux Density(B)

 Passing flux of per unit area  through the right angle to the flux is called flux density.

           B = Φ/A  Wb/m² 

 Absolute Permeability & Relative permeability

for the relative permeability, vacuum or free space permeability take as a reference. 

µ   -  Absolute permeability

µ_o -  Vacuum or free spas Permeability
µ_r - Relative permeability

              µ= µ_oµ_r

             µ = B/H