CBSE Class 10 Answered
Magnetic flux is a measure of the amount of magnetic field lines passing through a given surface.
Mathematically, the magnetic flux through a surface is defined as the integral of the magnetic field over the area of the surface. It is also the product of the average magnetic field times the perpendicular area that it penetrates.
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).
The magnetic flux is usually measured with a fluxmeter. The SI unit of magnetic flux is the weber (in derived units: volt-seconds). The CGS unit is the maxwell.