In series LCR circuit, 'R' represents resistance of electric bulb. If the frequency of a.c. supply is…
In series LCR circuit, 'R' represents resistance of electric bulb. If the frequency of a.c. supply is doubled, the value of inductance ' L ' and capacitance ' C ' should be
both doubled.
made four times.
made eight times.
both halved simultaneously.
Solution
In an LCR circuit
$\begin{aligned}
I=\frac{E}{Z} & =\frac{E}{\sqrt{R^2+\left(X_L-X_C\right)^2}} \\
& =\frac{E}{\sqrt{R^2+\left(2 \pi f L-\frac{1}{2 \pi f C}\right)^2}}
\end{aligned}$ To keep I constant, if f is doubled both L and C should be halved.