An electric current is expressed by a unit called _________.

ampere

The correct answer is option 2. ampere.

An electric current is expressed by a unit called Ampere.

The ampere (symbol: A) is the SI unit of electric current. It is defined as the flow of electric charge passing through a given point in a circuit per unit of time. One ampere is equivalent to one coulomb of charge passing through a point in a circuit per second. Therefore, the ampere is the standard unit used to measure electric current.