What is the practical unit of electrical resistance?

The practical unit of electrical resistance is the ohm. This unit measures how strongly a material opposes the flow of electric current. According to Ohm’s Law, which relates voltage (potential difference), current (flow of electric charge), and resistance, the relationship can be expressed as V = I × R, where V is the voltage in volts, I is the current in amperes, and R is the resistance in ohms. Therefore, when considering measurements in electrical circuits, ohms are essential for quantifying how much a material resists electrical currents, making it critical for understanding various applications in electronics and electrical engineering.

In contrast, watt is the unit of power, volt is the unit of electric potential difference, and joule is the unit of energy. While all these units relate to electrical concepts, they serve distinct purposes, whereas ohm specifically addresses resistance.