can be determined by the current I through coil and electronic velocity v of current I.

Can have a c shaped electromagnet pulling an iron bar with a force F by both of its

magnetic poles. The pulling force seems to be:

F=u U L L I I=(u L I) U L I,

where u is electromagnetic permeability of c shaped electromagnet coil core,

and U the electromagnetic permeability of the iron bar. The L is length of the wire

of the electromagnet coil. The coil has a voltage V accross it which increases is

current I is increased. Electron velocity v of current I is v=V. Can substitute v and V

into previous equation to get:

F=u U L L I I=u U L I V=u U L I v=u U Q,

where Q is the amount of electronic charge in the coil. The electronic charge

Q depends on velocity v, because if v is higher during a certain amount of time

period with same I, there should be more electron flow or charge Q.

The electron velocity v determines the amount of charge Q that goes through the wire

during a given time period t.

Q=v I.

This may show that the electromagnetic field intensity B from an electromagnetic

is also determined by the voltage V=v applied to the coil and electric current I.