In the context of resistors and Ohm's law, what is the SI unit of electrical resistance?

• A. Ohm ($\Omega$)
• B. Volt ($V$)
• C. Ampere ($A$)
• D. Watt ($W$)

Answer: (A)

Verified step by step guidance

1. Recall that electrical resistance is a measure of how much a material opposes the flow of electric current.
2. Ohm's law relates voltage (V), current (I), and resistance (R) through the formula \(R = \frac{V}{I}\), where \(R\) is resistance, \(V\) is voltage in volts, and \(I\) is current in amperes.
3. From the formula, the unit of resistance can be derived by dividing the unit of voltage (volt, V) by the unit of current (ampere, A).
4. Therefore, the SI unit of electrical resistance is volt per ampere, which is defined as the ohm, symbolized by the Greek letter omega (\(\Omega\)).
5. Hence, the correct SI unit for electrical resistance is the ohm (\(\Omega\)), not volt (V), ampere (A), or watt (W).