Impedance of Series LCR Circuit – Rankers Physics
Topic: Alternating Current
Subtopic: LR, RC and LCR Circuits

Impedance of Series LCR Circuit

Assertion (A): The impedance of series L-C-R circuit can be greater, equal or less than the resistance.
Reason (R): The minimum impedance of series LCR circuit depends over angular frequency of applied emf.
 
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution:

The impedance of a series \(LCR\) circuit is given by \(Z = \sqrt{R^2 + (X_L - X_C)^2}\). Since \((X_L - X_C)^2\) is always non-negative, \(Z\) is always greater than or equal to \(R\). Thus, (A) is false. The minimum impedance occurs at resonance, where \(Z_{min} = R\). This minimum value depends only on \(R\) and not on the angular frequency \(omega\). Thus, (R) is also false.

Leave a Reply

Your email address will not be published. Required fields are marked *