What is magnetic flux and magnetic flux density? Please keep it simple.

martin glen

Im revising for my A levels and I could really do with a simple, straight forward definition for magnetic flux and magnetic flux density. Can anyone please help? I'd be very grateful.

F=BIl

∅=BA

technician

Have you seen diagrams of magnetic fields or iron filings representations of magnetic fields?
They are represented by 'lines of force', these lines of force are given a unit in physics..... they are called Webers and the lines of force are known as the 'flux'.
In these magnetic field pictures the strong part of the field is near the magnet poles where the lines(flux ,Webers) are close together, so strength is something to do with how close the lines (Webers) are. The more lines per square metre (Webers per squ metre) the stronger the magnet.
Webers per square metre is given a special name 'magnetic flux density' known as magnetic field strength. It is measured in Webers per square metre which is given a special name.... Tesla.... we love to commemorate physicists in physics by naming units after them.
So... flux (phi) represents 'number of lines' measured in Webers
Flux density B is 'number of lines/m^2...webers/m^2 or Tesla
so flux = B x A ...... Webers = Tesla x m^2
Horrible, confusing mixture of units..... hope this helps

martin glen

Yeah that does help a lot, thank you!

asitiaf

so beautifully replied