Question

In an A.C. circuit, containing an inductance and a capacitor in series, the current is found to be maximum when the value of the inductance is 0.5 Henry and capacitance is 8$\mu$F . The angular frequency of the input A.C. voltage must be equal to

• A. 500 rad/sec
• B. 4000 rad/sec
• C. $5\times {10}^5$ rad/sec
• D. 5000 rad/sec

Answer 1

Answer: (A)

500 rad/sec

For maximum current impedance should be zero.

So, $Z=0$

$\Rightarrow X_L-X_C=0$

$\Rightarrow \omega L=\frac{1}{\omega C}$

$\Rightarrow \omega =\frac{1}{\sqrt{LC}}$

$=\frac{1}{\sqrt{0.5\times 8\times {10}^{-6}}}$

$=\frac{{10}^3}{2}$

$=500rad/sec$