Question

Same current is flowing in two AC circuits. First contains only inductance and second contain only capacitance. If frequency of AC is increased for both, the current will

• A. increase in first circuit and decrease in second.
• B. increase min both circuits.
• C. decrease in both circuits.
• D. decrease in first circuit and increase in second.

Answer 1

The correct option is D decrease in first circuit and increase in second.

Let the frequency of AC be $\nu$.

$\therefore$ $w=2\pi \nu$ ..........(1)

Reactance (or resistance) of the capacitor, $X_c=\frac{1}{wC}$

Reactance (or resistance) of the inductor, $X_L=wL$

Current in the circuit, $I=\frac{V}{X}$ where $X$ is the reactance of the circuit

$⟹$ When the frequency of the AC is increased, then the $X_c$ will decrease whereas $X_L$ will get increased. Hence for the same input AC voltage, current in the inductor circuit will decrease and that in capacitor circuit will increase.