1. A 470 resistor and a coil with 125 inductive reactance are in parallel. Both components are across a 15 V ac voltage source. Current through the inductor is
2. A 1.2 k resistor is in series with a 15 mH coil across a 10 kHz ac source. The magnitude of the total impedance is
3. When the frequency is decreased, the impedance of a parallel RL circuit
4. A 470 resistor and a 200 mH coil are in parallel. Both components are across a 1.5 kHz ac source. The total admittance of the circuit, in polar form, is
5. Referring to Problem 23, the reactive power is
6. A 12 k resistor is in series with a 90 mH coil across an 8 kHz ac source. Current flow in the circuit, expressed in polar form, is I = 0.30° mA. The source voltage, expressed in polar form, is
7. A 140 resistor is in parallel with an inductor having 60 inductive reactance. Both components are across a 12 V ac source. The magnitude of the total impedance is
8. When the frequency of the voltage applied to a series RL circuit is decreased, the impedance
9. In a parallel RL circuit, there are 3 A rms in the resistive branch and 3 A rms in the inductive branch. The total rms current is
10. A 47 resistor is in series with an inductive reactance of 120 across an ac source. The impedance, expressed in polar form, is
11. When the resistor voltage in a series RL circuit becomes less than the inductor voltage, the phase angle
12. Which of the following power factors results in less energy loss in an RL circuit?
13. Referring to Problem 20,
14. A 3.3 k resistor and a 120 mH coil are in parallel. Both components are across a 2 kHz, 12 V ac source. The total current in the circuit is
15. When the frequency of the voltage applied to a series RL circuit is increased, the phase angle
16. If a load is purely inductive and the reactive power is 12 VAR, the apparent power is
17. If the frequency is halved and the resistance is doubled, the impedance of a series RL circuit
18. Total current in an RL circuit always lags the source voltage.
19. The resistor voltage in an RL circuit is always out of phase with the current.
20. A filter passes certain frequencies and rejects others.
21. The power factor indicates how much of the apparent power is reactive power.
22. A power factor of 1 indicates a purely reactive circuit, and a power factor of 0 indicates a purely resistive circuit.
23. In an RL circuit, the impedance is determined by both the resistance and the inductive reactance combined.
24. The impedance of an RL circuit varies inversely with frequency.
25. The phase angle (θ) of a series RL circuit varies directly with frequency.