What is voltage?

• A. An electromotive force or potential difference expressed in volts.
• B. A measure of current flow.
• C. The rate of energy transfer per unit charge.
• D. A measure of resistance.

Answer: (A)

Voltage is the driving push that makes electric charges move. It’s the electromotive force or potential difference between two points, and it’s measured in volts. This means it represents the energy available to move each unit of charge from one point to another. The right description captures voltage as the energy per unit charge that can do work as charges flow through a circuit.

The other ideas refer to different electrical quantities: current is the actual flow of charges, resistance is how much a component opposes that flow, and the rate of energy transfer depends on both voltage and current (power).