Where an Inductor Stores Energy: Magnetic vs. Electric Fields Evaluate the statement: “Energy is stored by an inductor in an electrostatic field.”

Introduction / Context:
Energy storage mechanisms define how reactive components behave in AC and transient circuits. Capacitors store energy in electric (electrostatic) fields, whereas inductors store energy in magnetic fields. Misunderstanding this distinction leads to incorrect intuitions about phase relations and resonance.

Given Data / Assumptions:

• Ideal inductor L and ideal capacitor C.
• Linear materials without saturation or dielectric breakdown.
• Sinusoidal steady-state or transient analysis.

Concept / Approach:

The energy stored in an inductor is W_L = (1/2) * L * I^2, associated with the magnetic field generated by current flow. For a capacitor, W_C = (1/2) * C * V^2, associated with the electric field between plates. Thus, an inductor’s storage is magnetic, not electrostatic.

Step-by-Step Solution:

Verification / Alternative check:

Phase behavior corroborates: in an inductor, voltage leads current by 90 degrees due to energy cycling in the magnetic field; in a capacitor, current leads voltage by 90 degrees as energy cycles in the electric field. LC resonance exchanges energy between magnetic and electric fields, consistent with these storage mechanisms.

Why Other Options Are Wrong:

Any variant asserting electrostatic storage for inductors contradicts fundamental electromagnetics. Core material or frequency does not change the basic mechanism; these only affect magnitude and losses.

Common Pitfalls:

Equating large inductor voltage at high di/dt with electric-field storage; the induced voltage arises from changing magnetic flux (Faraday’s law), not from electrostatic energy storage.

Final Answer:

False