Q 12-07-112JEE MainJEE Main 2021 (27 Jul, Shift 2)Easy
A $100\ \Omega$ resistance, a $0.1\ \mu\text{F}$ capacitor and an inductor are connected in series across a $250$ V supply at variable frequency. Calculate the value of inductance of inductor at which resonance will occur. Given that the resonant frequency is $60$ Hz.
Answer: (D) $70.3$ H
$f = \dfrac{1}{2\pi\sqrt{LC}} \Rightarrow L = \dfrac{1}{4\pi^2f^2C}$
$$L = \frac{1}{4\times9.87\times3600\times10^{-7}} = \frac{1}{1.421\times10^{-2}} \approx 70.3\ \text{H}$$
Solution by Sreeraj P, M.Sc Physics