Alternating Current Question 16

Question 16 - 01 February - Shift 1

A series LCR circuit is connected to an ac source of $220 V, 50 Hz$. The circuit contain a resistance $R=100 \Omega$ and an inductor of inductive reactance $X_L=79.6 \Omega$. The capacitance of the capacitor needed to maximize the average rate at which energy is supplied will be $\mu F$.

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Answer: (40)

Solution:

Formula: Resonant Frequency

To maximize the average rate at which energy

supplied i.e. power will be maximum.

So in LCR circuit power will be maximum at the condition of resonance and in resonance condition

$X_L=X_C$

$79.6=\frac{1}{\omega C}$

$\therefore C=\frac{1}{2 \pi \times 50 \times 79.6}$

$\therefore C=40 \mu F$