In a circuit,the current lags behind the voltage by a phase difference of $\pi / 2$. The circuit will contain which of the following?

$A$ $40 \, \mu F$ capacitor is connected to a $200 \, V, 50 \, Hz$ $AC$ supply. The rms value of the current in the circuit is nearly $....... A$.

$A$ pure inductor of $50.0 \ mH$ is connected to a source of $220 \ V$. The frequency of the source is $50 \ Hz$. The rms current in the circuit (in $A$) will be $......$.

In the case of an inductor,

The inductive reactance of a coil is $R \ \Omega$. If the inductance of the coil is tripled and the frequency of the $A.C.$ supply is also tripled,then the new inductive reactance will be:

Keeping the source frequency equal to the resonating frequency of the series $LCR$ circuit,if the three elements,$L, C$ and $R$ are arranged in parallel,show that the total current in the parallel $LCR$ circuit is minimum at this frequency. Obtain the $rms$ current value in each branch of the circuit given below.
Figure shows a series $LCR$ circuit connected to a variable frequency $230\; V$ source. $L=5.0\; H, C=80\; \mu F, R=40\; \Omega$.