To reduce the resonant frequency in an `LCR` series circuit with a generator

Options

A. the generator frequency should be reduced
B. another capacitor should be added in parallel to the first
C. the iron core of the inductor should be removed
D. dielectric in the capacitor should be removed.

Answer

2

Explanation

Resonant frequency in series `LCR` circuit is
`upsilon_(r ) = (1)/(2 pi sqrt(LC))`
If capacitance `C` increases, the resonant frequency will reduce, which can be achieved by adding another capacitor in parallel to the first.