Question

An LCR circuit contains resistance of $110 \Omega$ and a supply of $220 V$ at $300 rad / s$ angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by $45^{\circ} .$ If on the other hand, only inductor is removed the current leads by $45^{\circ}$ with the applied voltage. The $rms$ current flowing in the circuit will be :

• A. $1 A$
• B. $2.5 A$
• C. $1.5 A$
• D. $2 A$

Answer 1

Answer: (D)

$2 A$

Answer 2

$\tan 45^{\circ}=\frac{1}{\omega C R}=\frac{\omega L}{R}$
$\Rightarrow X_{L}=X_{C}$
$\Rightarrow$ resonance
$i =\frac{ V }{ R }$
$=\frac{220}{110}=2 A$