What does an amp refer to?

• A. Unit of resistance
• B. Rate of flow of electrons (one coulomb)
• C. Driving force
• D. Power

Answer: (B)

An ampere is the unit for electric current—the rate at which electric charge moves past a point in a circuit. One ampere means one coulomb of charge passes per second. In a metal conductor, that amount of current corresponds to a huge number of electrons (about 6.24 x 10^18) flowing each second. The voltage provides the driving force that pushes the charges, but the ampere specifically measures the resulting flow of charge. Power is work done per second and equals voltage times current, and resistance describes how much current flows for a given voltage. So the amp refers to the rate of flow of electric charge.