What is the unit of electrical current?

• A. The volt (V)
• B. The ampere (A)
• C. The ohm (Ω)
• D. The watt (W)

Answer: (B)

Current is the rate at which electric charge flows through a circuit. The unit for this flow is the ampere, abbreviated A, defined as one coulomb of charge passing a point every second. This fits because it directly measures how much charge moves each second. Other units describe related ideas: volt measures potential difference (what pushes the charge), ohm measures resistance (how much the circuit resists the flow), and watt measures power (how much energy is transferred per second). These relate through I = V/R, so increasing voltage or lowering resistance increases current. For example, with a 2-volt supply across a 1-ohm resistor, the current is 2 amperes.