Magnetic Flux

The entire group of magnetic field lines, which can be considered to flow outward from the north pole of magnet, is called magnetic flux. Its symbol is the Greek letter (phi). A strong magnetic field has more lines of force and more flux than a week magnetic field.
THE MAXWELL
One Maxwell (Mx) unit equals one magnetic field line. In Fig.13-5, as an example, the flux illustrated is 6 Mx because there are 6 field lines flowing in or out for each pole. A 1-1b magnet can provide a magnetic flux of about 5000 Mx. This unit is named for James Clerk Maxwell (1831-1879), an important Scottish mathematical physicist who contributed much to electrical and field theory.