5555555555 7. A 120 Ω resistor is in parallel with a capacitor with a capacitive reactance of 40 Ω. Both components are across a 12 V ac source. What is the magnitude of the total impedance? (a) 37.9 Ω (b) 3.7 Ω (c) 14,400 Ω (d) 4,800 Ω
5555555555 20. A 200 Ω resistor, a coil with 30 Ω of reactance, and a capacitor of unknown reactance are in series across an ac source. The circuit is at resonance. Circuit impedance ________. (a) is 230 Ω (b) is 170 Ω (c) is 200 Ω (d) cannot be determined
5555555555 7. 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 ________. (a) 60 V (b) 660 V (c) 30 V (d) 300 V
5555555555 10. A 200 Ω resistor, a coil with 30 Ω of reactance, and a capacitor of unknown reactance are in series across an ac source. The circuit is at resonance. Circuit impedance ________. (a) is 230 Ω (b) is 170 Ω (c) is 200 Ω (d) cannot be determined
5555555555 11. A capacitor with 150 Ω of capacitive reactance is across an ac source. The impedance, expressed in polar form, is ________. (a) Z = 150 (b) Z = 150 ∠90° Ω (c) Z = 150 ∠–90° Ω (d) Z = 150 ∠180° Ω