Choke Coil vs Resistor in AC Circuits – Rankers Physics

Power in AC Circuits: Practice Problem & Solution

Assertion (A): Choke coil is preferred over a resistor to adjust current in an \( \text{ac} \) circuit. Reason (R): Power factor for inductance is zero.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Power in AC Circuits. Understanding the underlying formula is key to arriving at the correct answer below:

Choke coils reduce current in \( text{ac} \) circuits with minimal power loss, as power dissipation \( P = V_{rms} I_{rms} cosphi \) is low due to the phase angle approaching \( 90^circ \) for a purely inductive component. Thus, \( cosphi approx 0 \) for an ideal inductor. So, (A) and (R) are true, and (R) correctly explains (A).

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Similar Practice Questions

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1. The potential differences across the resistance, capacitance and inductance are $80 V$, $40 V$ and $100 V$ respectively in an LCR circuit. The power factor of this circuit is: (2016 - II)
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