Question

In an LCR circuit, at resonance, the value of the power factor is:

• A. 1
• B. 0
• C. 0.5
• D. 0.75
• E. infinity

Hint:

At resonance in an LCR circuit, the inductive and capacitive reactances cancel each other out, resulting in a purely resistive circuit with a power factor of 1.

Answer 1

The Correct Option is A

Step 1: At resonance in an LCR circuit, the impedance is purely resistive, meaning the total reactance (inductive and capacitive) is zero. 
Step 2: The power factor \( {pf} \) in an LCR circuit is given by: \[ {Power Factor} = \cos \theta \] At resonance, \( \theta = 0^\circ \), hence: \[ {Power Factor} = \cos 0^\circ = 1 \] Thus, the power factor at resonance is 1.