Question

What is the value of inductance $L$ for which the current is maximum in a series $LCR$ circuit with $C=10 \, \mu F$ and $\omega=1000 \, S^{-1}$ ?

• A. 1 mH
• B. cannot be calculated unless R is known
• C. 10 mH
• D. 100 mH.

Answer 1

Answer: (D)

100 mH.

Answer 2

Current is maximum at resonance
$\Rightarrow \omega^{2}=\frac{1}{L C}$
$\Rightarrow L=\frac{1}{\omega^{2} C}$
$=\frac{1}{(1000)^{2}\left(10 \times 10^{-6}\right)}=0.1 \,H$
$=100\, mH$