Halliday, Resnick & Walker — Electromagnetic Oscillations and Alternating Current: Problem 43

43 In an oscillating \(LC\) circuit, \(L = 25.0 \text{ mH}\) and \(C = 2.89 \text{ \(\mu\)F}\). At time \(t = 0\) the current is \(9.20 \text{ mA}\), the charge on the capacitor is \(3.80 \text{ \(\mu\)C}\), and the capacitor is charging. What are (a) the total energy in the circuit, (b) the maximum charge on the capacitor, and (c) the maximum current? (d) If the charge on the capacitor is given by \(q = Q \cos(\omega t + \phi)\), what is the phase angle \(\phi\)? (e) Suppose the data are the same, except that the capacitor is discharging at \(t = 0\). What then is \(\phi\)?