Passive Filters - Engineering

Q1:

A parallel resonant band-pass filter consists of a 6.8  resistor in series with a parallel network made up of an 8 H coil and a 120 pF capacitor. The output is taken across the capacitor/coil. Assume RW = 0 . What is the center frequency of the filter?

A 5.14 MHz

B 514 kHz

C 5.03 MHz

D 503 kHz

ANS:A - 5.14 MHz

Find voltage expression, we will be having (Xl-Xc) expression in the denominator.
Vo= 1/(R * (XL-Xc)/(Xl*Xc) + 1).
So max. voltage is occured, If XL=XC.
Hence, not exactly parallel.