In a laboratory experiment a student sets up a series RLC circuit with

PHYSICS · Subjective · CBSE · Physics · Alternating Current · Alternating Current

Problem

R = 30\,\Omega

L = 0.20\,\text{H}

and

C = 50\,\mu\text{F}

. The circuit is connected to a 220 V (rms) AC supply whose frequency can be varied. Initially the supply frequency is

200\,\text{Hz}

. (a) Calculate the inductive reactance, capacitive reactance, impedance and rms current when the frequency is

200\,\text{Hz}

. (b) The frequency is now doubled while keeping the supply voltage unchanged. Calculate the new values of

X_L

X_C

, impedance and rms current. (c) Find the ratio of the new current to the original current and state whether the current increases or decreases on doubling the frequency. (d) Explain physically why this change in current occurs when the frequency is doubled.

Related theory

Resonance in AC Circuits
AC Circuit Analysis
Alternating current
Series LCR circuit
AC applied to a series LCR circuit

Browse the problem library