ABSTRACT
Magnetic field strength (or magnetising force),
H = NI l
ampere per metre
where l is the mean length of the flux path in metres. Thus
m.m.f . = NI = Hl amperes
Problem 3. A magnetising force of 8000A/m is applied to a circular magnetic circuit of mean diameter 30 cm by passing a current through a coil wound on the circuit. If the coil is uniformly wound around the circuit and has 750 turns, find the current in the coil.
