What is the SI unit of power?

The SI unit of power is the watt (W). Power is the rate at which energy is transferred or converted. It describes how much energy is used or produced in a given amount of time. The watt is a derived unit, and it is defined as one joule per second.

Mathematically, power can be expressed as:

This means that when 1 joule of energy is transferred or converted in 1 second, the power involved is 1 watt. Power can be calculated using the formula:

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Where $P$ is power, $E$ is energy, and $t$ is time.

The watt is widely used to measure power in various fields, especially in electrical engineering and mechanics. For example, the power of light bulbs, electrical devices, engines, and machines is commonly expressed in watts. In electrical systems, power is calculated as the product of voltage and current:

Where $P$ is power in watts, $V$ is voltage in volts, and $I$ is current in amperes.

In practical terms, power is often expressed in larger units like kilowatts (kW), which represent 1,000 watts, or megawatts (MW), which represent 1 million watts. These larger units are commonly used in industries, power plants, and large-scale electrical systems.

The watt is essential in understanding energy efficiency, fuel consumption, and performance in various mechanical, electrical, and thermal systems. It helps quantify the effectiveness of processes that convert energy into useful work.