The value of power factor in pure inductor circuit is

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Explanation: In a pure inductor circuit, the voltage leads the current by a phase angle of $90^\circ$ (or $\frac{\pi}{2}$ radians). Since the power factor is defined as the cosine of this phase difference, the power factor is $\cos(90^\circ) = 0$.

Working Principle: An ideal inductor possesses no resistance, meaning it does not dissipate energy as heat. The magnetic field stores energy during one quarter of a cycle and releases it during the next, resulting in zero net real power consumption over a full cycle. Because $\phi = 90^\circ$, the active power $P = VI \cos(90^\circ) = 0$.

Key Formulas: $\phi = 90^\circ$ — Phase angle between voltage and current; $	ext{pf} = \cos(\phi) = \cos(90^\circ) = 0$ — Definition of power factor

Key Points: A pure inductor is a theoretical component with zero internal resistance.; The current in a pure inductor lags the voltage by $90^\circ$.; Real power (Active power) is zero in a pure inductive circuit.; The entire power involved is reactive power, measured in VAR (Volt-Ampere Reactive).

Advantages: Ideal for storing energy in magnetic fields; Used in filters to block high-frequency noise

Disadvantages: Not possible to achieve perfectly in practice due to winding resistance; Causes phase shift and low power factor issues in grids

Applications: Chokes and ballasts; Induction motors and transformers

Additional Info: In real-world inductors, there is always some winding resistance, resulting in a power factor slightly greater than 0.. Option B (1) represents a purely resistive circuit.. Option D (VI) represents apparent power in Volt-Amperes.

Answer: A is correct — The power factor of a pure inductor is 0 because the phase angle between voltage and current is $90^\circ$, and $\cos(90^\circ) = 0$.

Exam Tip: Always remember the mnemonic 'ELI' (Voltage E leads Current I in an Inductor) and 'ICE' (Current I leads Voltage E in a Capacitor) to avoid confusion during exams.

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