Magnetic Circuits

The flux density B = phi / A
The field intensity H = B / mu = phi / (A mu)
The flux density for tightly wound circular coil,
B = mu N i / l = mu H
Therefore,
H = N i / l
H = F / l
Or
F = N i = H l
F = B l / mu
F = phi l / (mu A)
Re-group the above equation as follows:
{F} = {phi} {l/(mu A)}
Compare with the Ohm's law:
V = I R