Question

(
4)
200 V
92.
A series LCR circuit is connected to an ac voltage
source. When Lis removed from the circuit, the
phase difference between current and voltage
is . If instead C is removed from the circuit,
the phase difference is again between current
3
and voltage. The power factor of the circuit is:
(1) 1.0
(2) - 1.0
(3)
zero
(4)
0.5​

Answer 1

Answer:

For only RC:- ϕRC=3π

tan(3π)=RXc⇒Xc=3R

For only RL :- ϕRL=3π

tan(3π)=RXL⇒XL=3R

For RL:-

tan(ϕ)=RXL−XC=R3R−3R=0⇒ϕ=0⇒cosϕ=1