Can we say that inside alternator magnetic force create now force (voltage)
In an alternator, the mechanical input spins the rotor, which has a magnetic field. This moving field induces a voltage in the stator windings. If there's no load connected to the stator, no current flows, and the mechanical energy required is only enough to overcome mechanical friction in the bearings and air resistance.

If a load is connected, allowing a current to flow in the stator windings, this current creates a new magnetic field that opposes the motion of the rotor's field. This is "felt" as additional mechanical resistance by the prime mover, and it must supply additional energy to keep the alternator running at the same speed.

Does this clarify things at all for you? Faraday's Law covers the relationship between magnetic fields, motion and voltage, while Ohm's Law deals with the relationship between voltage, current and power in the load.