Inductive reactance: choose the statement that most accurately describes its nature in practical circuits (assume sinusoidal steady-state conditions unless stated otherwise).

Introduction / Context:
Reactance is a frequency-dependent opposition to current flow caused by energy storage in inductors and capacitors. For inductors, this opposition is called inductive reactance and it grows with frequency. Distinguishing inductive reactance from related concepts like back emf helps clarify AC circuit behavior.

Given Data / Assumptions:

• Sinusoidal steady-state AC unless noted otherwise.
• Ideal inductor with reactance X_L = 2 * π * f * L.
• Direct current (dc) corresponds to f = 0 Hz.

Concept / Approach:
Inductive reactance X_L quantifies how an inductor resists changes in current. Since X_L = 2 * π * f * L, it is zero at dc (f = 0) and increases linearly with frequency. This means inductors impede AC but act as short circuits in ideal dc conditions (ignoring winding resistance).

Step-by-Step Solution:
Recall definition: X_L = 2 * π * f * L (ohms).For dc: f = 0 ⇒ X_L = 0, so no reactive opposition occurs.For ac: f > 0 ⇒ X_L > 0, providing frequency-dependent opposition.Therefore, the correct description is that inductive reactance opposes current flow in AC circuits.

Verification / Alternative check:
Impedance of an inductor is jX_L. The magnitude increases with f, consistent with reduced current for a given AC voltage (I = V / X_L). Time-domain view: the induced emf opposes changes in current, manifesting as reactance in the frequency domain.

Why Other Options Are Wrong:
Opposition in dc circuits: incorrect; ideal inductive reactance is zero at dc.Another term for counter emf: back emf is a phenomenon; reactance is a scalar magnitude in ohms.A force overcoming counter emf: not a meaningful electrical definition.None of the above: incorrect since (b) is accurate.

Common Pitfalls:
Equating physical back emf with the numerical reactance; forgetting the frequency dependence; ignoring winding resistance that exists in real inductors.

Final Answer:
Inductive reactance is an opposition to current flow in ac circuits