Which is the correct unit to measure electrical resistance?

Which is the correct unit to measure electrical resistance?

• A. Ohm
• B. Volt
• C. Ampere
• D. Watt

Answer: (A)

Resistance is the measure of how much a component opposes the flow of electric current. The unit used for that opposition is the ohm, symbolized by the Greek letter omega (Ω). By Ohm’s law, resistance equals voltage divided by current (R = V / I). So, if one volt across a component draws one ampere of current, its resistance is one ohm. This makes the ohm the correct unit for resistance. The other units measure different quantities: volt is potential difference, ampere is current, and watt is power. For example, a 10 Ω resistor with 2 A of current would have a voltage drop of V = I × R = 2 A × 10 Ω = 20 V.

Resistance is the measure of how much a component opposes the flow of electric current. The unit used for that opposition is the ohm, symbolized by the Greek letter omega (Ω). By Ohm’s law, resistance equals voltage divided by current (R = V / I). So, if one volt across a component draws one ampere of current, its resistance is one ohm. This makes the ohm the correct unit for resistance. The other units measure different quantities: volt is potential difference, ampere is current, and watt is power. For example, a 10 Ω resistor with 2 A of current would have a voltage drop of V = I × R = 2 A × 10 Ω = 20 V.