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Magnetising Field | Magnetising Force | Magnetising Intensity

Magnetising Field | Magnetising Force | Magnetising Intensity :- Suppose, you have a solenoid with n number of turns per unit length and i is the electric current flowing in it. When a magnetic material is placed in the core of the solenoid, the total magnetic field produced in the core due to the electric current i is :-

$\displaystyle B=\mu ni$ …..(1)

Here ni is the quantity due to which magnetic field (B) is generated in the core and the magnetic material kept in the core is magnetized, hence this quantity ni is called magnetising field or magnetising force or magnetising intensity H.

$\displaystyle H=ni$ …..(2)

Hence from equation (1),

$\displaystyle B=\mu H$ …..(3)

The magnetising field ( $\displaystyle \overrightarrow{H}$ ) is a vector quantity whose direction is in the direction of the magnetic field ( $\displaystyle \overrightarrow{B}$ ). Its value depends on the external free electric current and the geometry of the current carrying conductor.

In vector representation,

$\displaystyle \overrightarrow{B}=\mu \overrightarrow{H}$

Definition of Magnetising Field

The number of ampere-turns (ni) flowing in the unit length of the solenoid to generate the magnetic field (B) is called the magnetising field.

If there is free space/vacuum in the core of the solenoid, then the magnetic flux density/magnetic field/magnetic induction :-

$\displaystyle {{B}_{\text{0}}}={{\mu }_{0}}H$ …..(4)

Where μ₀ is the magnetic permeability of vacuum.

Unit of Magnetising Field

S.I. unit of Magnetising Field :-

ampere/meter i.e., Am^-1

C.G.S. unit of Magnetising Field :- Oersted

From equation (4),

$\displaystyle H=\frac{{{B}_{\text{0}}}}{{{\mu }_{0}}}$

Hence,

$\displaystyle 1\text{ }Oersted\text{ = }\frac{1\text{ }Gauss}{{{\mu }_{0}}}=\frac{{{10}^{-4}}T}{4\pi \times {{10}^{-7}}Tm{{A}^{-1}}}=\frac{{{10}^{3}}}{4\pi }\frac{A}{m}=79.57747\frac{A}{m}\approx 80\frac{A}{m}$

Magnetising Field | Magnetising Force | Magnetising Intensity

Definition of Magnetising Field

Unit of Magnetising Field

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