Exam: 086009RR - Inductors in AC Circuits solution

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Questions 1 to 25: Select the best answer to each question. Note that a question and its answers may be split across a page
break, so be sure that you have seen the entire question and all the answers before choosing an answer.
1. What is the parallel impedance of the circuit shown in the figure?
A. 64.9 Ω
B. 32.65 Ω
C. 100 Ω
D. 38.3 Ω
2. A circuit contains a 20 μH and a 60 μH inductor connected in parallel. These two inductors are in series
with a 1000 Ω resistor. The circuit has a source voltage of 30 VAC at 10,000 Hz. What is the total
inductive reactance of this circuit?
A. 0.942 Ω
B. 63.6 Ω
C. 2.43 Ω
D. 94.2 Ω
3. If an 80 mH inductor is in series with a 220 Ω resistor in a circuit with a source frequency of 1000 Hz,
what will be the phase angle (rounded) of the current with respect to the voltage?
A. 48°
B. 66°
C. 70°
D. 50°
4. What is the total circuit current shown in the figure?
A. 3.5 A
B. 2.5 A
C. 0.28 A
D. 0.75 A
5. What is the total circuit current of the circuit shown in the figure?
A. 0.06 A
B. 0.18 A
C. 0.19 A
D. 0.04 A
6. What is the inductive reactance of a 2 mH inductor at a frequency of 1000 Hz?
A. 12.56 Ω
B. 68.3 Ω
C. 20.25 Ω
D. 204.4 Ω
7. What is the inductive reactance of a 2 H inductor in a 60 Hz, AC circuit?
A. 0.08 Ω
B. 753.60 Ω
C. 120 Ω
D. 948 Ω
8. What is the total inductance of the circuit shown in the figure?
A. 2.05 H
B. 0.82 H
C. 51.25 H
D. 20.80 H
9. What is the current through the inductor shown in the figure?
A. 0.450 A
B. 1.21 A
C. 1.45 A
D. 450.50 A
10. What is the inductive reactance of the circuit's two coils as shown in the figure?
A. 308.98 Ω
B. 1029.92 Ω
C. 2574.80 Ω
D. 20.10 Ω
11. A circuit contains a 60 mH and a 40 mH inductor connected in parallel. The circuit has a source voltage
of 100 VAC and a frequency of 1000 Hz. What is the total inductive reactance (rounded) of the circuit?
A. 212 Ω
B. 194 Ω
C. 151 Ω
D. 173 Ω
12. A 10 mH inductor and a 100 Ω resistor are connected in parallel. The circuit is supplied with 24 VAC
at 2000 Hz. What is the impedance (rounded) of the circuit?
A. 78.23 Ω
B. 57.38 Ω
C. 108.71 Ω
D. 98.16 Ω
13. Which of the following denotes inductive reactance?
A. XL
B. R
C. H
D. Z
14. What is the time constant of a 2 mH inductor placed in series with a 400 Ω resistor?
A. 0.8 s
B. 0.6 s
C. 5 ms
D. 5 μs
15. What is the inductive reactance of the circuit shown in the figure?
A. 41.45 Ω
B. 6.91 Ω
C. 34.54 Ω
D. 41,448 Ω
16. A 100 mH inductor is placed in parallel with a 100 Ω resistor in a circuit. The circuit has a source
voltage of 30 VAC and a frequency of 200 Hz. What is the current through the inductor (rounded)?
A. 0.48 A
B. 0.36 A
C. 0.24 A
D. 0.42 A
17. A 10 mH inductor and a 100 Ω resistor are connected in parallel. The circuit is supplied with 24 VAC
at 2000 Hz. What is the phase angle (rounded) of this circuit?
A. 49.2°
B. 24.6°
C. 38.4°
D. 28.2°
18. What is the total inductance of the circuit shown in the figure?
A. 0.48 H
B. 1.0 H
C. 0.16 H
D. 0.63 H
19. What is the total current (IT) of the circuit shown in the figure?
A. 1.50 A
B. 1.31 A
C. 1.71 A
D. 0.88 A
20. A 6 mH, a 2 mH, and a 10 mH inductor are placed in series with a 1000 Ω resistor in a circuit. The
circuit has a source voltage of 60 VAC at 1000 Hz. What is the total inductive reactance of this circuit?
A. 113.04 Ω
B. 93.80 Ω
C. 121.64 Ω
D. 86.42 Ω
21. A parallel circuit has a resistance of 280 Ω and an inductive reactance of 360 Ω. What is this circuit's
impedance?
A. 221.02 Ω
B. 540 Ω
C. 368 Ω
D. 191.80 Ω
22. What is the inductive reactance of a 0.5 H inductor connected with a 1000 Ω resistor in an AC circuit
supplied with 48 VAC at 100 Hz?
A. 0.31 Ω
B. 500 Ω
C. 314 Ω
D. 150.72 Ω
23. What is the time constant of a 20 mH inductor in series with a 230 Ω resistor?
A. 86.96 s
B. 86.96 μs
C. 0.09 s
D. 900 ms
24. A 10 mH inductor and a 100 Ω resistor are connected in parallel. The circuit is supplied with 24 VAC
End of exam
at 2000 Hz. What is the total circuit current (rounded)?
A. 0.31 A
B. 0.29 A
C. 0.42 A
D. 0.46 A
25. A series circuit contains a 30 mH inductor and a 200 Ω resistor. What is the total circuit current
(rounded) if the applied voltage is 60 V and the frequency is 1000 Hz?
A. 0.44 A
B. 0.22 A
C. 1.24 A
D. 0.84