Question

In a RLC series circuit at resonance, the value of the power factor is :

• A. Infinity
• B. zero
• C. $\frac{1}{\sqrt{2}}$
• D. $1$

Answer 1

The correct option is D $1$

At resonance, $X_L=X_c$

$⟹Z=\sqrt{R^2+(X_L-X_c{)}^2}=R$

Power factor $\cos \varphi =\frac{R}{Z}=\frac{R}{R}=1$