Electromotive Force | Definition, Symbols, & Units | Britannica

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External Websites

• University of Iowa Pressbooks - College Physics - Back Emf
• University of Hawaii Pressbooks - College Physics chapters 1-17 - Motional Emf
• Physics LibreTexts - Electromotive Force
• OpenStax - College Physics 2e - Electromotive Force: Terminal Voltage
• Mustansiriyah University - Electromotive Force
• Saskatchewan Open Education Resources - Introduction to Electricity, Magnetism, and Circuits - Electromotive Force
• BCCampus Publishing - Electromotive Force: Terminal Voltage

Ask the Chatbot a Question Also known as: E, emf Written and fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors History Table of Contents Table of Contents Ask the Chatbot

electromotive force, energy per unit electric charge that is imparted by an energy source, such as an electric generator or a battery. Energy is converted from one form to another in the generator or battery as the device does work on the electric charge being transferred within itself. One terminal of the device becomes positively charged, the other becomes negatively charged. The work done on a unit of electric charge, or the energy thereby gained per unit electric charge, is the electromotive force. Electromotive force is the characteristic of any energy source capable of driving electric charge around a circuit. It is abbreviated E in the international metric system but also, popularly, as emf.

Abbreviation: E or emf (Show more) Related Topics: electric charge electric current volt potential difference (Show more) See all related content

Despite its name, electromotive force is not actually a force. It is commonly measured in units of volts, equivalent in the metre–kilogram–second system to one joule per coulomb of electric charge. In the electrostatic units of the centimetre–gram–second system, the unit of electromotive force is the statvolt, or one erg per electrostatic unit of charge.

The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Erik Gregersen.