Electromotive Force | Definition, Symbols, & Units | Britannica

Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos electromotive force Introduction References & Edit History Quick Facts & Related Topics Images Quizzes Electricity: Short Circuits & Direct Currents Contents Science Physics Matter & Energy CITE verifiedCite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook X URL https://www.britannica.com/science/electromotive-force Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

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
• Mustansiriyah University - Electromotive Force
• OpenStax - College Physics 2e - Electromotive Force: Terminal Voltage
• BCCampus Publishing - Electromotive Force: Terminal Voltage

electromotive force physics Ask Anything Homework Help 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 Last updated Jan. 6, 2026 •History Britannica AI Ask Anything Table of Contents Table of Contents Ask Anything

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.