Which unit is used to measure electrical resistance?

Electrical resistance is measured in ohms, which is a fundamental unit in the International System of Units (SI). Ohms quantify how much opposition a material or component presents to the flow of electric current when a voltage is applied. According to Ohm's Law, resistance (R) is defined as the ratio of voltage (V) to current (I), symbolically represented as R = V/I. This relationship shows how resistance impacts the flow of electricity in a circuit, making ohms a critical concept for understanding electrical systems.

The other units listed—watts, volts, and amperes—serve different purposes within electrical calculations. Watts measure power, which is the rate at which electrical energy is transferred or converted. Volts measure electric potential difference or voltage. Amperes measure electric current, which is the flow of electric charge in a circuit. Each of these units plays a vital role in understanding electrical principles, but it is ohms that specifically addresses the concept of resistance.