Inductive behavior — phase relation: In a predominantly inductive series R–L circuit driven by a sinusoid (|X_L| > R), does the current lag the applied voltage?

Introduction / Context:Knowing whether current leads or lags voltage is central to AC analysis and power factor correction. Inductors store energy in magnetic fields and impose a positive reactive component, shifting current in time relative to voltage.

Given Data / Assumptions:

• Series R–L circuit, sinusoidal source.
• |X_L| > R indicates inductive dominance.
• No capacitor is present in this basic scenario.

Concept / Approach:In phasor form, Z = R + jX_L. The current phasor I = V/Z lags V by angle φ where tan φ = X_L / R > 0. A positive φ means current lags voltage. As X_L increases or R decreases, φ approaches 90 degrees.

Step-by-Step Solution:

Verification / Alternative check:Oscilloscope with dual channels (voltage and shunt-resistor current sense) shows current zero crossings occurring after voltage zero crossings in inductive circuits.

Why Other Options Are Wrong:

Common Pitfalls:Confusing mnemonic “ELI the ICE man”: voltage (E) leads current (I) in an inductor (L); current leads voltage in a capacitor (C).

Final Answer:Yes, current lags the voltage