Question: A resistance R, inductance L and capacitance C are in series. The source frequency is adjusted to be equal to resonant frequency. The lower half power frequency is ω1. Another resistance R is added in series with the circuit. The new lower half power frequency will be
[A].ω1
less than ω1
more than ω1
either more than ω1 or less then ω1
[A].
[B].
[C].
[D].
Answer: Option C
Explanation:
As R increases, Q decreases, bandwidth = . Therefore, bandwidth increases. Hence lower half power frequency will be less than ωr.