Which unit is used to measure electrical current?

• A. Amperes
• B. Ohms
• C. Watts
• D. Volts

Answer: (A)

Electrical current is the rate at which electric charges flow through a circuit. The unit that quantifies this flow is the ampere, abbreviated A. One ampere means that one coulomb of charge passes a point each second. So current is measured in amperes. The other units describe related quantities: ohms measure resistance, volts measure electric potential difference (the push that drives current), and watts measure power (the rate of energy transfer). For example, with a 6-volt source across a 3-ohm resistor, the current is I = V/R = 6/3 = 2 amperes.