The coil of inductance $0.25 \mathrm{mH}$ has a reactance of $330 \Omega$, when connected to an a.c. source.…
The coil of inductance $0.25 \mathrm{mH}$ has a reactance of $330 \Omega$, when connected to an a.c. source. The frequency of a.c. source is (Take $\left.\pi=\frac{22}{7}\right)$
$210 \mathrm{kHz}$
$105 \mathrm{kHz}$
$420 \mathrm{kHz}$
$330 \mathrm{kHz}$
Solution
We know inductive reactance is given by $X_L=2 \pi f L$, where $f$ is the frequency of the source and $L$ the inductance of the coil.
$f=\frac{X_L}{2 \pi L}$
Given, $L=0.25 \mathrm{mH}$ and $C=330 \Omega$,
$f=\frac{330 \Omega}{2 \pi(0.25 \mathrm{mH})}=210 \mathrm{kHz}$