Resistance is measured in units of __________.

• A. Volts
• B. Watts
• C. Ohms
• D. Amperes

Answer: (C)

Resistance describes how much a component or material opposes current flow, and its unit is the ohm. An ohm is defined as the resistance between two points of a conductor when a constant potential difference of one volt, applied to those points, produces a current of one ampere. In other words, Ohm’s law V = I × R ties them together, so R = V / I. This is why resistance is measured in ohms: it’s the ratio of voltage to current for a component.

Volts measure electric potential difference, amperes measure current, and watts measure power. So voltage and current are not resistance; they relate to resistance through Ohm’s law. In practice, you might test resistance with a multimeter to diagnose circuits; very high resistance suggests an open circuit, very low resistance points to a short, while a specific resistance value identifies a component like a resistor.