What defines a watt in terms of electric power?

A watt is defined as the amount of electric power that is used when one ampere of current flows through a conductor with a voltage of one volt. This relationship is expressed in the formula: Power (P) = Voltage (V) × Current (I). Thus, when the current is one amp and the voltage is one volt, the power consumed is one watt. This is a fundamental concept in electrical engineering and provides a clear relationship between current, voltage, and power, allowing for calculations and understanding of electrical systems.

The other options, while related to concepts of electricity, do not accurately define a watt. The second choice references Ohm's law rather than the relationship of power directly, which is not specific to the definition of a watt. The third choice discusses power at standard voltage but does not specify the relationship needed to define a watt. The fourth option introduces watt-hours, which refers to energy rather than the instantaneous power defined by one amp at one volt.