Which of the following is a unit of electric potential?

• A. Ohm
• B. Farad
• C. Joule
• D. Volt

Answer: (D)

Electric potential is the energy available per unit charge to drive charges from one point to another. The unit for that potential difference is the volt. A volt is defined as one joule per coulomb, so a potential difference of one volt means moving one coulomb of charge would require or supply one joule of energy. In circuit terms, voltage is what pushes current through wires and components, and it’s what a voltmeter measures.

The other units shown aren’t for electric potential: the ohm measures resistance, the farad measures capacitance, and the joule measures energy. While energy relates to potential, the specific unit for potential is the volt.