An inductor of 0.5 mH, a capacitor of 200 $\mu$F and a resistor of 2 $\Omega$ are connected in series with a 220 V ac source. If the current is in phase with the emf, the frequency of ac source will be ____________ $\times$ 102 Hz.
Answer (integer)
5
Solution
<p>Current will be in phase with emf when</p>
<p>$\omega L = {1 \over {\omega C}}$</p>
<p>$$ \Rightarrow \omega = {1 \over {\sqrt {LC} }} = {1 \over {\sqrt {5 \times {{10}^{ - 4}} \times 2 \times {{10}^{ - 4}}} }}$$</p>
<p>$\Rightarrow \omega = {{{{10}^4}} \over {\sqrt {10} }}$ rad/s</p>
<p>$\Rightarrow f = {1 \over {2\pi }} \times {{{{10}^4}} \over {\sqrt {10} }}$ Hz</p>
<p>$\Rightarrow$ f $\simeq$ 500 Hz</p>
About this question
Subject: Physics · Chapter: Alternating Current · Topic: AC Circuits: R, L, C
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