In a series $L-C-R$ circuit,the capacitance is changed from $C$ to $2C$. To obtain the same resonance frequency,the inductance should be changed from $L$ to:

$A$ resistor of $50 \Omega$,an inductor of self-inductance $\left(\frac{3}{\pi^2}\right) H$,and a capacitor of unknown capacity are connected in series to an a.c. source of $100 \ V$ and $50 \ Hz$. When the voltage and current are in phase,the value of capacitance is (nearly):

The $Q$ factor of a series $\text{LCR}$ circuit with $L=2 \text{ H}$,$C=32 \mu\text{F}$ and $R=10 \Omega$ is :-

$A$ series $LCR$ circuit is shown in the figure. Where the inductance of $10 \ H$,capacitance $40 \ \mu F$,and resistance $60 \ \Omega$ are connected to a variable frequency $240 \ V$ source. The current at resonating frequency is (in $A$)

An $AC$ circuit contains a resistance of $1 \text{ k}\Omega$, a capacitor of $0.1 \mu\text{F}$, and an inductor of $1 \text{ mH}$ connected in series. The resonance frequency of the circuit is approximately: (in $kHz$)

An $AC$ circuit consists of an inductor of inductance $0.5 \, H$ and a capacitor of capacitance $8 \, \mu F$ in series. The current in the circuit is maximum when the angular frequency of the $AC$ source is