The unit of electromotive force, called the volt, is the electric pressure produced by cutting 100,000,000 lines per second, usually expressed 108.
3. By joining in series a number of conductors or coils moving in a magnetic field, the electromotive forces in the separate parts are added together.
The reason for this is apparent by considering a coil of wire having several turns and moving in a magnetic field so as to cut magnetic lines. During the movement, the lines cut by the first turn are successively cut by all the other turns of the coil, hence, the total number of lines cut is equal to the number cut by a single turn multiplied by the number of turns. The electromotive forces therefore of the separate turns are added.
EXAMPLE—If a coil of wire of 50 turns cut 100,000 lines in 1⁄100 of a second, what will be the induced voltage?
The number of lines cut per second per turn of the coil is
100,000 × 100 = 10,000,000.
The total number of lines cut by the coil of 50 turns is
10,000,000 × 50 = 500,000,000.
which will induce a pressure of