Which unit is used for voltage?

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

Answer: (B)

Voltage is the electric potential difference that pushes charges to move through a circuit. The unit for this quantity is the volt (symbol V). One volt represents one joule of energy per coulomb of charge that moves between two points. This potential difference acts like electrical “pressure,” determining how much current will flow when there is resistance. The volt is named after Alessandro Volta. Other units measure related quantities: the watt measures power (energy transfer per unit time), the ampere measures current (the rate of charge flow), and the ohm measures resistance (opposition to current). Knowing V = I × R helps connect these concepts by showing how voltage relates to current and resistance.