In a series $LR$ circuit with $X_L = R$. Power factor is $P_1$. If a capacitor of capacitance $C$ with $X_c = X_L$ is added to the circuit the power factor becomes $P_2$. The ratio of $P_1$ to $P_2$ will be :

The output of a step-down transformer is measured to be $48 \,V$ when connected to a $12 \,W$ bulb. The value of peak current is

In an $A.C.$ circuit,the current:

Given below are two statements $:$ one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A) :$ Choke coil is simply a coil having a large inductance but a small resistance. Choke coils are used with fluorescent mercury-tube fittings. If household electric power is directly connected to a mercury tube,the tube will be damaged.
Reason $(R):$ By using the choke coil,the voltage across the tube is reduced by a factor $\left(R / \sqrt{R^2+\omega^2 L^2}\right)$,where $\omega$ is the angular frequency of the supply,$R$ is the resistance,and $L$ is the inductance. If the choke coil were not used,the voltage across the tube would be the same as the applied voltage. In the light of the above statements,choose the most appropriate answer from the options given below $:$

$A$ series $RLC$ circuit is shown here. The source frequency $f$ is varied, but the current is kept unchanged. Which of the curves showing changes of $V_C$ and $V_L$ with frequency would be valid for the circuit under consideration?

In an $AC$ circuit, the instantaneous current is zero when the instantaneous voltage is maximum. In this case, the source may be connected to:
$A$. Pure inductor.
$B$. Pure capacitor.
$C$. Pure resistor.
$D$. Combination of an inductor and capacitor.
Choose the correct answer from the options given below: