Ampere is the unit of electrical current.

• A. Volt
• B. Ampere
• C. Ohm
• D. Watt

Answer: (B)

The main idea is understanding the different electrical quantities and their units. Electric current is the flow of electric charge, and the unit used to quantify that flow is the ampere. An ampere means that one coulomb of charge passes a given point every second, so current I can be thought of as dQ/dt. This is why current is measured in amperes.

Other units measure related but different properties: the volt measures electric potential difference (how much driving "pressure" pushes charges), the ohm measures resistance (how much a material resists the flow of current), and the watt measures electrical power (the rate at which energy is transformed or used). In formulas, voltage and current relate through resistance (V = IR), and power relates to both (P = VI).