List of top Physics Questions on KCL/ KVL in AC Circuits asked in CBSE CLASS XII

A capacitor and an inductor are connected in series across an ac source of voltage of variable frequency. The frequency is increased continuously. The nature of the circuit before and after the resonance will be:
Plot a graph to show the variation of reactance of the element with the frequency of the applied voltage.
An ac source of voltage \( V = V_0 \sin \omega t \) is connected to a circuit element \( X \). It is observed that the current flowing through \( X \) varies as \( I = I_0 \sin\left(\omega t - \frac{\pi}{2}\right) \).
(a) Identify the element \( X \) and write the expression for its reactance.
Establish the expression for impedance of the circuit when elements X, Y, and Z are connected in series to an AC source. Show the variation of current in the circuit with the frequency of the applied AC source.
You are given three circuit elements X, Y, and Z. They are connected one by one across a given ac source. It is found that \( V \) and \( I \) are in phase for element X. \( V \) leads \( I \) by \( \frac{\pi}{4} \) for element Y while \( I \) leads \( V \) by \( \frac{\pi}{4} \) for element Z. Identify elements X, Y, and Z.
Two long straight thin wires AB and CD have linear charge densities \( 10 \, \text{mC/m} \) and \( -20 \, \text{mC/m} \), respectively. They are kept parallel to each other at a distance of 1 m. Find the magnitude and direction of the net electric field at a point midway between them.