LC Circuits with variable frequency

[greenday1260]

Homework Statement

A variable capacitor with a range from 10 pF to 420 pF is used with a coil to form a variable-frequency LC circuit to tune the input to a radio.

(a) What ratio of maximum frequency to minimum frequency that can be obtained with such a capacitor?
ANS:__________

(b) If this circuit is to obtain frequencies from 0.54 MHz to 1.60 MHz, the ratio computed in (a) is too large. By adding a capacitor in parallel to the variable capacitor, this range can be adjusted. What capacitance should be added to obtain the desired frequency range?
ANS:___________pF

(c) What inductance should the coil have to obtain the desired frequency range?
ANS:___________H

Homework Equations

\omega= \frac{1}{\sqrt{LC}}

The Attempt at a Solution

no idea pls help

 

[George Jones]

For (a), assume that the value of L is unknown, but fixed (constant).

What value for the variable capacitance gives you the biggest frequency?

What value for the variable capacitance gives you the smallest frequency?