What is the definition of voltage?

Voltage is defined as the energy given to each coulomb of charge as it moves through an electric field. This relationship is fundamental in understanding electrical circuits. In other words, voltage measures the potential difference between two points in a circuit, indicating how much energy is available to drive charge through the circuit.

When a charge moves due to this potential difference, it gains energy in the process, which can be used to perform work, such as lighting a bulb or powering a motor. The unit of voltage, the volt (V), quantifies this energy per unit charge, with one volt being equal to one joule of energy per coulomb of charge.

The other options do not accurately capture the essence of voltage. For instance, current refers to the flow rate of charge, which is a different concept, and the energy consumed by appliances relates more to power and energy usage rather than the potential difference itself. Similarly, the total number of coulombs in a system does not pertain to the energy associated with charge movement or potential difference.