All Problems Electric Oscillations
Problem 4.124
A series circuit consisting of a capacitor with capacitance \(C=22 \mu \mathrm{F}\) and a coil with active resistance \(R=20 \Omega\) and inductance \(L=0.35 \mathrm{H}\) is connected to a source of alternating voltage with amplitude \(V_{m}=180 \mathrm{~V}\) and frequency \(\omega=314 \mathrm{~s}^{-1}\). Find: (a) the current amplitude in the circuit; (b) the phase difference between the current and the external voltage; (c) the amplitudes of voltage across the capacitor and the coil.
4.124. (a) \(I_{m}=V_{m} / \sqrt{R^{2}+(\omega L-1 / \omega C)^{2}}=4.5 \mathrm{~A} ;\) (b) \(\tan \varphi=\) \(=\frac{\omega L-1 / \omega C}{R}, \varphi=-60^{\circ}\) (the current is ahead of the voltage); (c) \(V_{C}=I_{m} / \omega C=0.65 \mathrm{kV}, V_{L}=I_{m} V \overline{R^{2}+\omega^{2} L^{2}}=0.50 \mathrm{kV}\)