Question

Which of the following is TRUE?

• A. Power factor of a series resonance circuit is zero
• B. Circuit impedance is minimum at resonance in a series resonance circuit
• C. Power dissipated is minimum at resonance in a series resonance circuit
• D. Circuit current is minimum at resonance in a series resonance circuit

Hint:

For a series RLC circuit at resonance, \[ \boxed{ Z=R,\qquad I=\text{Maximum},\qquad \text{Power factor}=1. } \]

Answer 1

The Correct Option is B

Step 1: Recall the properties of series resonance. At resonance, \[ X_L=X_C, \] so the net reactance becomes zero. Hence, \[ Z=R, \] which is the minimum impedance of the circuit.

Step 2: Identify the correct statement. At resonance, \[ \boxed{ \begin{aligned} \text{Impedance} &\rightarrow \text{Minimum}, \text{Current} &\rightarrow \text{Maximum}, \text{Power factor} &\rightarrow 1. \end{aligned} } \] Therefore, \[ \boxed{(B)} \] is the correct answer.