Question

An ac circuit consists of a series combination of circuit elements x and y. The current is ahead of the voltage in phase by 4 . If element x is a pure resistor of 100 , (a) name the circuit element y. (b) calculate the rms value of current, if rms value of voltage is 141 v. (c) what will happen if the ac source is replaced by a dc source ?

Answer 1

the current is ahead then the circuit is capacitive.

hence Y has to be a capacitor.

As impedence =

R

2

+X

c

2

thus,

R=100 Ω

R

X

c

=tan

4

π

X

C

=R=100

Z=100

2

Therefore,

I

rms

=

Z

V

rms

=

100

2

141

=09987

Nearly 1Ω

solution