In the context of resistors and Ohm’s law, what quantity describes the opposition to electric current flow in a circuit?

• A. Electrical power, measured in watts ($W$)
• B. Electrical resistance, measured in ohms ($\Omega$)
• C. Electric current, measured in amperes ($A$)
• D. Electric potential difference (voltage), measured in volts ($V$)

Answer: (B)

Verified step by step guidance

1. Understand that the problem is asking for the quantity that represents the opposition to electric current flow in a circuit.
2. Recall Ohm's law, which relates voltage (V), current (I), and resistance (R) in a circuit: \(V = I \\times R\).
3. Recognize that resistance (\(R\)) is the property that opposes the flow of electric current, causing the current to be reduced for a given voltage.
4. Note that resistance is measured in ohms, symbolized by the Greek letter omega (\(\\Omega\)).
5. Differentiate resistance from other quantities: electrical power (watts, \(W\)) is the rate of energy transfer, current (amperes, \(A\)) is the flow of charge, and voltage (volts, \(V\)) is the electric potential difference driving the current.