The amount of work done in moving an electrical charge through a conductor from a point of high electrical potential (or high electrical pressure) to one of lower electrical potential is dependent on:
- The amount of charge, and
- The potential difference.
Potential difference is the difference in electric potential or electrical pressure between two points. This difference in electrical potential can be measured by a voltmeter. The volt (V) is the SI unit of potential difference.
The movement of electrons in electro-chemical cells can be compared to water flowing or being pumped from one point to another. Water moves from a point of high pressure to a point of lower pressure. Thus, a pressure difference is required. The work done in moving the water through a pipe depends on the volume of water and the pressure difference.
By definition, Electrical Work [J] = Charge [C] x Potential Difference [V]
Therefore, one volt is equivalent to one joule of energy per coulomb of charge. In other words, IV = 1J / 1C.