Current, I (A)
Current is the rate of flow of charge measured in amperes.
The amount of charge that passes in one second when the current is one ampere.
Potential difference (voltage)
The energy converted per unit charge moved. 1 volt is equal to 1 joule of energy moving 1 coulomb of charge through a component.
Provided temperature is constant, the current through an ohmic conductor is directly proportional to the potential difference across it.
Work done = efficiency (as decimal) * electrical energy input
Electrical energy input = work done / efficiency