Magnetic Flux

Definition - What does Magnetic Flux mean?

Magnetic Flux or Magnetic Flux Density is the amount of electromagnetic field that passes through a surface when it is brought near an electric current. Thus, it is proportional to the number of magnetic field lines which pass through a surface. Magnetic Flux is denoted by symbol and its SI unit is Weber (Wb) which is equal to volt-seconds.

Petropedia explains Magnetic Flux

Magnetic Flux () is equal to the product of average magnetic field and area perpendicular to the magnetic field. It is written as: = B.A, where “B” represents magnetic field and “A” represents area perpendicular to the magnetic field B. In real world since the surfaces have strange shapes, Magnetic Flux through surface “S” is written as:

Magnetic Flux through closed surface is zero and is written as:

Whereas, Magnetic Flux through an open surface is expressed by Faraday’s Law and is written as


\mathcal{E} is EMF

is closed area or shape which changes with time.

dl is vector element

v is the velocity

E is the electric field, and

B is the Magnetic Flux

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