The unit of electrical resistance in Georg Ohm’s law is the ohm.
Ohm’s law describes the relationship between voltage, current, and resistance with the equation V = IR. One ohm is the resistance that permits a current of one ampere when a potential difference of one volt is applied. The unit is named after German physicist Georg Ohm, whose 1827 work established the relationship for many conductors.
The ohm is represented by the Greek letter omega, Ω. It is an SI derived unit, while the volt and ampere measure voltage and current respectively. A watt measures power, so it is not interchangeable with resistance.
Real components do not always obey Ohm’s law perfectly. Metal wires often behave approximately ohmically over a useful range, but devices such as diodes and incandescent-filament lamps have resistance that changes with voltage, current, or temperature.