Question

A series L - C - R circuit has a resistance of $30\Omega$ & an impedance of $55\Omega$. What average power is delivered to the circuit when applied A.C voltage is 220 volt?

• A. 360 Watt
• B. 480 Watt
• C. 120 Watt
• D. 560 Watt

Answer 1

The correct option is B 480 Watt

$P_{avg}=V_{rms}{I}_{rms}\cos \varphi =V_{rms}\frac{V_{rms}}{Z}\cos \varphi =V_{rms}\frac{V_{rms}}{Z}\frac{R}{Z}$
$=(\frac{V_{rms}}{Z}.\frac{V_{rms}}{Z})R$
$=(\frac{220}{55}.\frac{220}{55})\left(30\right)$
$=4\times 4\times 30=480Watt$