Difficulty: Easy
Correct Answer: Yes, current lags the voltage
Explanation:
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:
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
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