Magnetic Flux - Formula, SI Unit & CGS Unit


Magnetic Flux 

A sub-discipline of physics in the field of electromagnetism is the magnetic flux through a surface, which refers to the surface integral of the magnetic field's (B) normal component passing through that surface. To be specific, magnetic flux is defined as the number of magnetic field lines passing through a given closed surface. In this particular scenario, the area under consideration can be in any orientation corresponding to the direction of the magnetic field and of any size.

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Symbol and Formula of Magnetic Flux

Magnetic flux is denoted by the Greek letter Phi and has the symbol Φ or ΦB

To calculate the magnetic flux, we can use the formula given below:

ΦB = B.A = B A cosΦ

Where, 

ΦB = Magnetic Flux

B = Magnetic Field

A = Area

Φ = Angle at which the magnetic field lines pass through the given surface area

Fluxmeter is used to measure magnetic flux. 

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SI Unit of Magnetic Flux 

Weber (Wb) is the SI unit of magnetic flux, which is named after Wilhelm Eduard Weber, a German physicist. A flux density of one Weber per square meter or Wb/m2 is one Tesla, denoted by T (explained in the next section). Quite often, Weber is expressed in a multitude of other units, as shown below:

Wb = kg m2/s2 A = V.s = H.A = T.m2 = J/A = 108Mx

Where, Wb = Weber, T = Tesla, V = volt, m = meter, J = joule, s = second, H = Henry, A = ampere, and Mx = Maxwell.

 

CGS Unit of Magnetic Flux

The CGS unit of magnetic flux is Maxwell (Mx) or Abweber (abWb).

 

Fundamental Unit of Magnetic Flux

The fundamental unit of magnetic flux is Volt-seconds.

 

Understanding the Term Magnetic Flux Density

The force acting per unit length on a wire placed perpendicular (at right angles) to the magnetic field per unit current is the magnetic flux density (B).

  • Tesla (T) or Kg s-2 A-1 is the SI unit of magnetic flux density (B).

  • The magnetic flux density, denoted by the symbol B, is a vector quantity

  • The CGS unit of magnetic flux density is Gauss, which is abbreviated as G or Gs

The formula for calculating the magnetic flux density is as follows:

B = F/I L

Where,

F = total force acting on the wire

I = current flowing through the wire

L = length of the wire

 

Submultiples of Weber(Wb)

Value                

SI Symbol              

Name             

10-1 Wb

dWb

deciweber

10-2 Wb

cWb

centiweber

10-3 Wb

mWb

milliweber

10-6 Wb

µWb

microweber

10-9 Wb

nWb

nanoweber

10-12 Wb

pWb

picoweber

10-15 Wb

fWb

femtoweber

10-18 Wb

aWb

attoweber

10-21 Wb

zWb

zeptoweber

10-24 Wb

yWb

yoctoweber

 

Multiples of Weber 

Value

SI Symbol       

Name

101 Wb

daWb

decaweber

102 Wb

hWb

hectoweber

103 Wb

kWb

kiloweber

106 Wb

MWb

megaweber

109 Wb

GWb

gigaweber

1012 Wb

TWb

teraweber

1015 Wb

PWb

petaweber

1018 Wb

EWb

exaweber

1021 Wb

ZWb

zettaweber

1024 Wb

YWb

yottaweber