Purely inductive AC circuit: which statement most accurately describes its opposition and phase relationship?

Introduction / Context:In a purely inductive circuit (ideal inductor, no resistance), the impedance is entirely imaginary and proportional to frequency. Understanding both what constitutes the opposition to current and the correct phase relationship between voltage and current is fundamental in AC analysis.

Given Data / Assumptions:

• Ideal inductor with inductance L.
• Sinusoidal steady-state operation at frequency f.
• No series or parallel resistance present.

Concept / Approach:

• Inductive reactance: X_L = 2 * π * f * L provides the opposition to current (in ohms).
• Phasor relationship: For an inductor, current lags voltage by 90°, or equivalently, voltage leads current by 90°.

Step-by-Step Reasoning:

Verification / Alternative check:

Why Other Options Are Wrong:

• Resistance provides the only opposition: False for a pure inductor (R = 0).
• Combinations of R and X_L: Describes RL circuits, not purely inductive.
• Voltage lags current by 90°: Reversed; in an inductor, current lags voltage.
• None of the above: Incorrect because X_L-only opposition is correct.

Common Pitfalls:

• Mixing up inductor and capacitor phase relationships.
• Forgetting frequency dependence of X_L, which changes current magnitude.

Final Answer: