What is the unit symbol for resistance?

The unit symbol for resistance is represented by the Greek letter omega (Ω). This symbol is universally recognized in electrical engineering and physics to denote resistance in ohms, which is the standard unit for measuring this property. Ohm's law relates voltage, current, and resistance in an electrical circuit, making it fundamental in understanding how electrical components interact.

The other options represent different electrical quantities: R is often used as a variable to denote resistance itself, V is the symbol for voltage, and A signifies amperes, which measure current. Each of these has its own specific role in the context of an electrical circuit, but none of them indicate the unit of resistance. Therefore, Ω is the correct representation for resistance in accordance with the SI (International System of Units) standards.