Cambridge Encyclopedia » Cambridge Encyclopedia Vol. 23

electromotive force - Explanation of electromotive force, Electromotive force in thermodynamics, Electromotive force and potential difference, Electromotive force generation

emf source charges energy

The work done by some source in separating electrical charges to produce a potential difference capable of driving current round a circuit; often abbreviated emf. The term ‘force’ is a misnomer; generally, emf is a property of the source, whereas potential difference depends on both source and current flow. A source of emf transfers energy to the circuit by doing work in raising potential. For example, a battery is a source of emf in which chemical energy moves charges to the terminals, making one positive, the other negative. The emf is work done on the charges to bring about this separation: an emf of one volt means that the battery expends one joule of energy to bring about the separation of one coulomb of charge.

User Comments

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or