Suppose you have a circuit consisting of a resistance R = 54 ?, an inductor with L = 36.4 mH and internal resistance r = 30 ?, and a capacitor C = 8.13 ?F. There is no power supply in the circuit. Instead, the capacitor has been charged to 7.17 V and suddenly connected to the rest of the circuit.
What is the frequency of the damped oscillations of this circuit?