Electromotive Force
- When charge passes through a power supply such as a battery, it gains electrical energy
- The electromotive force (e.m.f.) is defined as:
The amount of chemical energy converted to electrical energy per unit charge when charge passes through a power supply
- e.m.f. is measured in Volts (V)
Definition of e.m.f. with regards to energy transfer
- This can also be written as:
- E.m.f. is:
- represented by the symbol ε (greek letter epsilon)
- not actually a force, but a measure of energy transferred per coulomb of charge
- is measured in volts (V), which is J C−1 in S.I. units
- e.m.f. is also the potential difference across the cell when no current is flowing
- e.m.f. can be measured by connecting a high-resistance voltmeter around the terminals of the cell in an open circuit
e.m.f. is measured using a voltmeter connected in parallel with the cell
