When a coiled wire is introduced near a magnet, the magnetic lines of force pass through the coil. This causes the magnetic flux to change. Magnetic flux is represented by the symbol , therefore we can say that = BAcos(a) and the resulting unit will be , where T is the unit for magnetic field and is the unit for area.
His laws state that:
is the electromotive force, measured in volts;
is the change in magnetic flux, measured in webers;
is the change in time, measured in seconds.
In the case of a solenoid:
N is the number of loops in the solenoid.
The negative sign in both equation above is a result of Lenz's law, named after Heinrich Lenz. His law states that the electromotive force (EMF) produces a current that opposes the motion of the changing magnetic flux.