Question

For L-C-R A.C. circuit resonance frequency is 600 Hz and frequencies at half power points are 550 Hz and 650 Hz. What will be the Q-factor? choose the correct option from the given options.
(A) 1/6
(B) 1/3
(C) 6
(D) 3

Answer 1

Answer:

c) 6

Explanation:

Circuit resonance frequency = w = 600Hz (Given)

Frequency = w1 = 500 (Given)

Frequency = w2 = 600 Hz (Given)

In a L-C-R AC circuit, the half power band width is the difference between two frequencies, namely w2 and w1, that corresponds to the current I( rms, max)/ √2 or equivalently half power in the series resonance curve.

The Q factor is the measure of sharpness of resonance curve defined as -

Q = wo/(w2-w1), where wo is the resonance frequency.

Thus,  

Q = 600/(650–550)

Q = 600/100

Q = 6.