Important terminology of Magnetism:
The amount of magnetic field produced by a magnetic source is called magnetic flux. Magnetic flux is denoted by the Greek letter φ(phie). The SI unit of magnetic flux is weber.
Magnetic flux density
Magnetic flux density is the flux per unit area at right angles to the flux.
Flux density, B = φ/A wb⁄m^2
The SI unit of flux density is Tesla.
The force produced by current through a coil of wire is called magnetomotive force (mmf). It is the force by which a magnetic field is produced.
An increase in the mmf increases the strength of the magnetic field.
F= NI, where N is the number of turns in the coil and I is the electric current through the circuit.
Magnetomotive force is measured in ampere- turns (A-T).
Magnetic field intensity (H)
Magnetic field intensity is mmf per unit length. It is denoted by H and unit is amp-turn per meter or amp/m.
H = mmf/L=NI/L
UNIT: amp-turn per meter.