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Magnetisation And Magentic Intensity - Practice Questions & MCQ

Edited By admin | Updated on Sep 25, 2023 25:23 PM | #NEET

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  • Magnetisation and magentic intensity is considered one of the most asked concept.

  • 5 Questions around this concept.

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A heater coil is cut into two equal parts and only one part is now used in the heater.

Relative magnetic permeability of a magnetic medium is 1000. If the magnetic field at any point in the medium be 0.1wb.m^-^2What will be the value of magnetic intensity and intensity of magnetisation at that point.

Concepts Covered - 1

Magnetisation and magentic intensity

 The magnetic intensity (H)-

The magnetic intensity of the magnetizing field is given by  H=\frac{B_0}{\mu_0 }   

 And its S.I. unit is A/m while its C.G.S. Unit is oersted.

Magnetization (M) -

Magnetization is a process in which a normal material is converted into a magnetic material by exposing it to an external magnetic field. The magnetic intensity is the reason due to which a normal material changes into magnetic material.

We define magnetization M of a sample to be equal to its net magnetic moment per unit volume i.e M=\frac{m_{net}}{V}

Consider a long solenoid of n turns per unit length and carrying a current i 

The magnetic field in the interior of the solenoid is given by \mathbf{B}_{0}=\mu_{0} \mathbf{n} \mathbf{I}

If n=\frac{N}{L} then \mathbf{B}_{0}=\frac{\mu_{0} \mathbf{N} \mathbf{I}}{L} where N=number of turns and L=length of solenoid

Using   H=\frac{B_0}{\mu_0 } So we can write H=\frac{B_0}{\mu_0 }=\frac{NI}{L}

If the interior of the solenoid is filled with a material with non-zero magnetization then the material will magnetize.

And the field inside the solenoid will be greater than B0.

The net B field in the interior of the solenoid may be expressed as

B=B_{0}+B_{m}

B - total magnetic field

B_{0} - the magnetic field in vacuum

B_{m} - magnetic field due to magnetization of the material

And B_{m}is proportional to the magnetization M of the material and is expressed as B_m=\mu _0M

And using H=\frac{B_0}{\mu_0 } we can write B_o=\mu _0H

So we get B=B_{0}+B_{m}=\mu _0H+\mu _0M=\mu _0(H+M)

So we get  H=\frac{B}{\mu _0}-M

The Magnetization (M) of material is influenced by The magnetic intensity (H)

So the elation between M and H is given as \mathrm{M=\chi H}

where \mathrm{\chi } is called magnetic susceptibility. And it is a measure of how a magnetic material responds to an external field.

Using \mathrm{M=\chi H}   in   B= \mu _0(H+M) 

we get \begin{array}{l}{\mathbf{B}=\mu_{0}(\mathbf{1}+\chi) \mathbf{H}} {=\mu_{0} \mu_{\mathbf{r}} \mathbf{H}} {=\mu \mathbf{H}}\end{array}

where \mu _r=(1+\chi ) is called relative magnetic permeability of the substance.

and     \mu =\mu _0\mu _r=\mu _0(1+\chi )  is the magnetic permeability of the substance 

 

 

 

 

 

 

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Magnetisation and magentic intensity

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