Electro Magnetic Induction And Alternating Currents Question 140
Question: In the circuit , the ac source gives a voltage $ V=20\cos (2000,t). $ Neglecting source resistance, the voltmeter and ammeter reading will be [KCET (Engg.) 2002]
Options:
A) 0V, 0.47A
B) 1.68V, 0.47A
C) 0V, 1.4 A
D) 5.6V, 1.4 A
Show Answer
Answer:
Correct Answer: D
Solution:
$ Z=\sqrt{{{(R)}^{2}}+{{(X_{L}-X_{C})}^{2}};} $
$ R=10,\Omega ,X_{L}=\omega L=2000\times 5\times {{10}^{-3}}=10,\Omega $
$ X_{C}=\frac{1}{\omega C}=\frac{1}{2000\times 50\times {{10}^{-6}}}=10,\Omega i.e.,Z=10,\Omega $
Maximum current $ i_{0}=\frac{V_{0}}{Z}=\frac{20}{10}=2A $
Hence $ i_{rms}=\frac{2}{\sqrt{2}}=1.4,A $ and $ V_{rms}=4\times 1.41=, $ 5.64 V
