What is the unit of resistance in an electrical circuit?

The unit of resistance in an electrical circuit is the ohm. The concept of resistance is fundamental in understanding how electrical circuits operate, as it quantifies how much a material opposes the flow of electric current.

Resistance is defined using Ohm's Law, which states that the voltage (V) across a conductor is proportional to the current (I) flowing through it, with the resistance (R) acting as the constant of proportionality: V = I × R. In this relationship, the unit of resistance, the ohm, can be expressed in terms of other electrical units. One ohm is equivalent to one volt per ampere (1 Ω = 1 V/A). This means that when a voltage of one volt is applied across a conductor and results in a current of one ampere, the resistance of that conductor is one ohm.

This understanding of resistance is crucial for analyzing and designing electrical circuits, as it impacts how components operate together, the power dissipated in circuits, and the overall functionality of electrical systems. The other options represent different electrical units: coulombs refer to electric charge, henries are units of inductance, and watts measure power, none of which relate directly to the concept of resistance.