Q129 / 180 · AIIMS 2016 · Physics
A series resonant $L C R$ circuit has a quality factor (Q-factor) 0.4 . If $R=2 \mathrm{k} \Omega, C=0.1 \mu \mathrm{F}$, then the value of inductance is
- A$0.1 \mathrm{H}$
- Correct answerB$0.064 \mathrm{H}$
- C$2 \mathrm{H}$
- D$5 \mathrm{H}$
Solution
$\begin{aligned} & \text { } Q=\frac{1}{R} \sqrt{\frac{L}{C}} \text { or } \frac{L}{C}=(Q R)^2 \\ & \therefore \quad L=\left(0.4 \times 2 \times 10^3\right)^2 \times 0.1 \times 10^{-6}=0.064 \mathrm{H}\end{aligned}$
Hence, the correct answer is option: 'B'.