What does resistance describe in an electrical circuit?

• A. The energy provided to the circuit.
• B. The amount a material slows down the flow of current.
• C. The device that converts current to light.
• D. The speed of electrons.

Answer: (B)

Resistance describes how much a material or component opposes the flow of electric current. It sets how much current will flow for a given voltage, as captured by Ohm’s law (I = V/R). A higher resistance means greater opposition, so the current is smaller for the same voltage. Resistance depends on what the material is, its size and shape, and also temperature, and it’s measured in ohms. It’s not about the energy provided to the circuit (that’s the voltage or power), it’s not about a device that creates light, and it isn’t the speed of the electrons (drift velocity).