What does a volt measure?

A volt is defined as the unit of electric potential difference, which quantifies the amount of work needed to move a unit charge between two points in an electric field. More specifically, one volt is the potential difference that will move one coulomb of charge with one joule of energy. This means that if there is a potential difference of one volt between two points and a current of one ampere flows through a conductor between them, one joule of energy is expended per second.

Understanding this concept is critical in electrical engineering and physics, as it directly relates to how circuits function. This is key in applications involving batteries, power supplies, and various electrical devices where voltage influences the flow of current and the energy transfer in the system.

The other options describe different electrical concepts, such as thermal energy, resistance, and current, which are distinct from the definition of a volt. A volt specifically addresses potential difference, making it a foundational concept in both thermodynamics and electricity.