Core concept checkpoint: In basic circuit theory, resistance is best described as which of the following?

Introduction / Context:
Three foundational quantities in circuits are voltage (electric potential difference), current (charge flow), and resistance (opposition to current). Confusing these leads to wrong expectations about how circuits behave under different loads and sources. This item reinforces the precise role played by resistance.

Given Data / Assumptions:

• Ohm’s law applies for the element being discussed.
• Linear, time-invariant behavior around the operating point.
• No reactive elements are considered in the definition.

Concept / Approach:
Ohm’s law V = I * R shows resistance as the proportionality between voltage and current. For a given applied voltage, a larger resistance yields a smaller current, hence resistance opposes current flow. It does not oppose voltage; rather, voltage is the cause that pushes current through resistance, producing heat at P = I^2 * R.

Step-by-Step Solution:

Verification / Alternative check:
Compare two lamps on the same battery: the one with higher resistance draws less current and glows dimmer, illustrating the opposing effect on current.

Why Other Options Are Wrong:

• Opposition to voltage: Misstates causality; voltage is the driving potential.
• Same as current or same as voltage: They are distinct physical quantities with different units (A, V, Ω).

Common Pitfalls:
Equating a voltage drop with ”loss” of voltage as if resistance consumes voltage; voltage is not consumed—energy is dissipated as heat while voltage remains the measure of potential difference.

Final Answer:
opposition to current