  Experimental validation of the Faraday's law of electromagnetic induction
(EMI) is performed when an electromotive force is generated in thin copper
turns, located inside a large magnetic coil. It has been established that the
electromotive force (emf) value should be dependent not only on changes of the
magnetic induction flux through a turn and on symmetry of its crossing by
magnetic power lines also. The law of EMI is applicable in sufficient
approximation in case of the changes of the magnetic field near the turn are
symmetrical. Experimental study of the induced emf in arcs and a direct section
of the conductor placed into the variable field has been carried out. Linear
dependence of the induced emf on the length of the arc has been ascertained in
case of the magnetic field distribution symmetry about it. Influence of the
magnetic field symmetry on the induced emf in the arc has been observed. The
curve of the induced emf in the direct section over period of current pulse is
similar to this one for the turns and arcs. The general law of EMI for a
curvilinear conductor has been deduced. Calculation of the induced emf in the
turns wrapped over it and comparison with the experimental data has been made.
The proportionality factor has been ascertained for the law. Special conditions
have been described, when the induced emf may not exist in the presence of
inductive current. Theoretical estimation of the inductive current has been
made at a induced low voltage in the turn. It has been noted the necessity to
take into account the concentration of current carriers in calculation of the
induced emf in semiconductors and ionized conductors.
