Magnetic Flux

Magnetic flux is the product of the average magnetic field times the perpendicular area that it penetrates. It is a quantity of convenience in the statement of Faraday's Law and in the discussion of objects like transformers and solenoids. In the case of an electric generator where the magnetic field penetrates a rotating coil, the area used in defining the flux is the projection of the coil area onto the plane perpendicular to the magnetic field. Since the SI unit for magnetic field is the Tesla, the unit for magnetic flux would by Tesla m2. This unit combination has the historical name Weber (Wb).

Magnetic flux illustrationElectric flux
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Magnetic field concepts

Faraday's Law concepts
 
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Magnetic Flux Illustrations

The contribution to magnetic flux for a given area is equal to the area times the component of magnetic field perpendicular to the area. For a closed surface, the sum of magnetic flux is always equal to zero (Gauss' law for magnetism). No matter how small the volume, the magnetic sources are always dipole sources (like miniature bar magnets), so that there are as many magnetic field lines coming in (to the south pole) as out (from the north pole).

Index

Magnetic field concepts

Faraday's Law concepts
 
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