A series LCR circuit
Question:

A series LCR circuit is designed to resonate at an angular frequency $\omega_{0}=10^{5} \mathrm{rad} / \mathrm{s}$. The circuit draws $16 \mathrm{~W}$ power from $120 \mathrm{~V}$ source at resonance. The value of resistance ‘ $R$ ‘ in the circuit is ________$\Omega$.

Solution:

At resonance

$\mathrm{P}=\frac{\mathrm{V}^{2}}{\mathrm{R}}$

$\mathrm{R}=\frac{\mathrm{V}^{2}}{\mathrm{P}}=\frac{(120)^{2}}{16}$

$=900 \Omega$