Question

In the circuit shown in figure, the $AC$ source gives a voltage $V=20\cos \left(2000t\right)$. Neglecting source resistance, the voltmeter and ammeter readings will be

• A. $0V,2.0A$
• B. $0V,1.4A$
• C. $5.6V,1.4A$
• D. $8V,2.0A$

Answer 1

Answer: (C)

$5.6V,1.4A$

Here, $X_L=\omega L=2000\times 5\times {10}^{-3}\Omega =10\Omega$

$X_C=\frac{1}{\omega C}=\frac{1}{2000\times 50\times {10}^{-6}}\Omega =10\Omega$

$X_L=X_C$. Hence this is a case of resonance.

$⟹i=\frac{V}{R}=\frac{\left(20/\sqrt{2}\right)}{10}=1.4A$

Voltmeter reading=$1.4\times 4volt=5.6V$