Question

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

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

Answer 1

Answer: (A)

$100mH$

Given : $C={10}^{-6}$ $F$ $w=1000$ $s^{-1}$

Current is maximum at resonance, i.e. when $wL=\frac{1}{wC}$

$\therefore$ $L=\frac{1}{w^{2}C}$

$L=\frac{1}{(1000{)}^2\times 10\times {10}^{-6}}$

$⟹$ $L=0.1$ $H=100mH$