What is the unit of power in the International System of Units (SI)?

The unit of power in the International System of Units (SI) is the Watt (W). Power is defined as the rate at which energy is transferred or converted. When we talk about electrical power, for example, it is calculated as the product of voltage and current. Therefore, one Watt is equivalent to one Joule per second, meaning that if one Joule of energy is used in one second, that corresponds to a power output of one Watt.

In this context, the other options represent different physical quantities: Joules (J) measure energy, Newtons (N) measure force, and Pascals (Pa) measure pressure. Each of these units serves a distinct purpose within various fields of science and engineering, but none of them represent the concept of power. This clear distinction solidifies why the Watt is the correct and relevant unit of measurement for power within the SI framework.