Question

The power in series $RLC$ - circuit with $AC$ source is given by :

• A. Zero
• B. $VI\sin \varphi$
• C. $VI$
• D. $VI\cos \varphi$

Answer 1

The correct option is D $VI\cos \varphi$

$P=V_{rms}Inrs\cos \varphi$

$\cos \varphi =$ power factor

$\cos \varphi =\frac{V_R}{V}=\frac{iR}{iz}=$ $\frac{R}{\sqrt{(x_C-x_L{)}^2+R^2}}$

Option - D is correct.