Which quantity is measured in amperes?

• A. Current
• B. Potential difference
• C. Electromotive force
• D. Electric field

Answer: (A)

Current is the flow of electric charge through a conductor per unit time, so it is measured in amperes. An ampere equals one coulomb of charge passing a point every second, which captures the rate at which charges move. Think of electrons streaming through a wire: the faster or more charges pass each moment, the bigger the current.

Potential difference is the driving push that moves charges and is measured in volts. Electromotive force is the energy provided per unit charge by a source, also in volts. The electric field is the force acting on a unit positive charge in space, measured in newtons per coulomb or volts per metre. So amperes specifically quantify the rate of charge flow, not the energy per charge or the field strength. In practice, you measure current with an ammeter placed in series in a circuit.