Which of the following describes a watt?

A watt is defined as a measure of power, which quantifies the rate at which energy is consumed or generated. In the context of electrical systems, one watt is equivalent to one joule per second, signifying that if one joule of energy is used every second, then one watt of power is being consumed.

This concept is central to understanding how devices consume energy; for example, a 60-watt light bulb uses 60 joules of energy every second it is on. This definition is crucial because it helps differentiate between energy (measured in joules) and power (measured in watts), where power indicates the rate at which energy is transferred or converted.

The other options pertain to different electrical measurements. Energy over time does relate to power but does not directly define what a watt is; instead, it illustrates how the unit of power functions. Voltage is a measure of electrical potential difference, while electrical current refers to the flow of electric charge. Each of these is fundamental to electrical systems, but they help define different concepts within the larger framework of electricity, rather than serving as a direct definition of what a watt represents.