What is resistance?

• A. The energy delivered to the circuit
• B. The rate of energy transfer
• C. The opposition to current flow
• D. The path electrons take

Answer: (C)

Resistance is the opposition to current flow in a circuit. It’s a property of a material or component that makes it harder for electrons to move when a voltage is applied. Because of this opposition, the current that flows for a given voltage is reduced. The relationship is expressed by Ohm’s law: R = V / I, so higher resistance means smaller current for the same voltage. Resistance arises from electrons colliding with atoms and with lattice vibrations or impurities, which converts some of the electrical energy into heat. Temperature often increases resistance in metals as atoms vibrate more and hinder electron passage. This concept is distinct from how much energy is delivered to the circuit (power) or the rate of energy transfer, and it’s not about the exact path electrons take—it's about how easily they can move through the material and geometry of the component.