What does a watt measure?

A watt is defined as a unit of power in the International System of Units (SI). It measures the rate at which energy is used or produced. Specifically, one watt corresponds to one joule of energy being transferred or used per second. This means that when you say a device uses a certain number of watts, you are indicating how much electric energy that device consumes over the course of one second. This is crucial in understanding the efficiency and consumption of electrical devices, as it allows for the comparison of their energy usage.

In contrast, other choices refer to concepts that do not define what a watt measures. The speed of electric current refers to the flow rate of electrons in a circuit, which is more related to voltage and current but is not quantified in watts. The resistance of electric current is measured in ohms and indicates how much a material opposes the flow of electricity. The pressure of electric current is not a standard electrical term; voltage is the correct term that describes the potential difference that pushes electric current through a circuit. Therefore, the correct interpretation of a watt is specifically about measuring how much electric energy is consumed in one second.