Electromotive Force

—The force which starts and maintains a current of electricity through a conductor; it is commonly measured in terms of a unit called the volt. It is abbreviated E. M.. F. Unit E. M. F. is that pre ure which forces one ampere of electricity through a resistance of one ohm. Thompson uses the term electromotive force as follows: “The term ‘electromotive force’ is employed to denote that which moves or tends to move electricity from one place to another. In this particular case it is obviously the result of difference of potential and proportional to it; just as in water pipes, a difference in level produces a pre ure, and the pre ure produces a flow as saon as the tap is turned on, so difference of potential produces electromotive force, and electromotive force sets up a current as soon as a circuit is completed for the electricity to flow through.” Electromotive Force of Induction. The electromotive force set up in a circuit by the influence of induction. Electromotive Force of Polarization. —The counter E. M. F. set up in a primary Electromotive Force of Self-induction. cell by the polarization due to the formation of hydrogen bubbles upon the surface of the copper plate.