Question

A sinusoidal voltage of peak value 300 V and an angular frequency $\omega$ = 400 rad/s is applied to series L-C-R circuit, in which R = 3 $\Omega$ L = 20 mH and C = 625 $\mu F.$ The peak current in the circuit is

• A. 30 $\sqrt{2}$ A
• B. 60 A
• C. 100 A
• D. 60 $\sqrt{2}$ A

Answer 1

Answer: (B)

60 A

Answer 2

The impedance of the circuit is $Z=\sqrt{{{R}^{2}}+{{({{Z}_{L}}-{{X}_{C}})}^{2}}}$ ${{X}_{L}}=\omega L=400\times 20\times {{10}^{-3}}=8H$ ${{X}_{C}}=\frac{1}{\omega C}=\frac{1}{400\times 625\times {{10}^{-6}}}=4C$ $Z=\sqrt{{{(3)}^{2}}+{{(8-4)}^{2}}}=5$ $i=\frac{E}{Z}=\frac{300}{5}=60A$