Science, Tech, Math › Science Electromotive Force Definition (EMF) What Is Electromotive Force? Share Flipboard Email Print A transformer coil generates electromotive force or emf. FroggyFrogg, Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated July 10, 2019 Electromotive force is the electric potential generated by either a electrochemical cell or a changing magnetic field. It is also known as voltage. It is electrical action produced by a non-electrical source, such as a battery (converts chemical energy to electrical energy) or generator (converts mechanical energy into electrical energy). Although the term contains the word "force" it's not akin to a force in physics that would be measured in newtons or pounds.Electromotive force is commonly denoted by the acronym emf, EMF or a cursive letter E.The SI unit for electromotive force is the volt.