- Home/
- GATE ELECTRICAL/
- GATE EE/
- Article
In a Certain Series LCR Circuit
By BYJU'S Exam Prep
Updated on: September 25th, 2023
A certain series L, C, R circuit with L=10 mH and capacitance of L=10 μF when connected to an alternating source of voltage 100 V draws a maximum current of 7 amp (rms value) when the frequency of the source is adjusted for the maximum power condition. What is the value of approximate resistance of the circuit?
- 10.22Ω
- 21.22Ω
- 7.22Ω
- 5.12Ω
Table of content
Answer: A. 10.22
In the certain series, LCR circuit resistance R=10.22.
Solution
Power maximum power to occur in series LCR circuit the system should be under resonance,
That means angular frequency ω=1/√LC
So, at ω=1/√LC series LCR circuit will under resonance, and at resonance maximum power will be dissipated in resistor.
Then ω=1/√(10 mH×10 μF)=√10×103 rad/sec
L=10 mH×√10×103=10√10
1C=1/10 μF×√10×103=√10×10
Then impedance Z=√R2+(XL–XC)2
At resonance XL=XC
So, impedance Z=R
Maximum current Imax=7√2 A (in LCR circuit maximum current will occur at resonance)
Imax=Vmax/Z
Imax=Vmax/R
7√2 A=100 V/R
R=100 V/7√2 A=10.101 ohm.
☛ Related Questions: