A series circuit contains an inductance of and a resistance of

PHYSICS · Multi-part · CBSE · Physics · Alternating Current · Alternating Current

Problem

A series circuit contains an inductance of

0.30\,\text{H}

and a resistance of

20\,\Omega

. It is connected to a

50\,\text{Hz}

a.c. source. A variable capacitor of

100\,\mu\text{F}

is now inserted in series. (i) Compute the inductive and capacitive reactances of the circuit at the given frequency. (ii) Using these values, calculate the phase angle between the source voltage and the circuit current. (iii) Hence find the rms current in the circuit when the applied voltage is

220\,\text{V}

(rms) and determine the average power absorbed by the circuit. (iv) For what value of capacitance will the average power supplied by the source reduce to zero in this circuit? Show your working clearly.

Related theory

Power in AC Circuits
AC Circuit Analysis
Series LCR circuit
AC applied to a series LCR circuit
Alternating Current

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