4. A 9 mH coil is in parallel with a 0.015 µF capacitor across an 18 kHz ac source. The coil's internal resistance, RW, is 60 Ω. The circuit impedance is
5. A 90 Ω resistor, a coil with 30 Ω of reactance, and a capacitor with 50 Ω of reactance are in series across a 12 V ac source. The current through the resistor is
7. A 6.8 kΩ resistor, a 7 mH coil, and a 0.02 µF capacitor are in parallel across a 17 kHz ac source. The coil's internal resistance, RW, is 30 Ω. The equivalent parallel resistance, Rp(eq), is
8. A certain series RLC circuit with a 200 Hz, 15 V ac source has the following values: R = 12 Ω, C = 80 µF, and L = 10 mH. The total impedance, expressed in polar form, is
9. A 24 Ω resistor, an inductor with a reactance of 120 Ω, and a capacitor with a reactance of 120 Ω are in series across a 60 V source. The circuit is at resonance. The voltage across the inductor is