1. A voltage of 100 VDC is applied across a resistor, and the temperature of the resistor is measured. Which of the voltage waveforms shown in the figure, when applied across the resistor, would produce that same temperature?
A. Waveform 1, waveform 2, or waveform 3
B. Waveform 2 or waveform 3
C. Waveform 1 or waveform 2
D. Waveform 1 or waveform 3
2. Look at the voltage/current relationship displayed by the waveforms in the figure. A circuit that has this voltage/current relationship is
A. capacitive.
B. resonant.
C. resistive.
D. inductive.
3. Look at the circuit diagram shown in the figure. When all three switches are closed, the power in the primary circuits is
A. less than that of any single secondary winding.
B. 200 W.
C. at maximum.
D. reduced by eddy current losses.
4. Look at the circuit diagram that's shown in the figure. Suppose that switch Si was moved to the A position. How long after switch Si is moved to the A position will the current through the inductor reach its steady-state value?
A. 5 microseconds
B. 10 microseconds
C. 25 microseconds
D. 50 microseconds
5. Look at the circuit diagram that's shown in the figure. Immediately after switch S1 is moved to the B position,
A. the voltage across R1 is at a maximum.
B. the magnetic field surrounding Li is at a minimum.
C. the magnetic field surrounding L1 is at a maximum.
D. the voltage across R2 is at a minimum.
6. Look at the circuit that's shown in the figure. The total impedance of this circuit is 100Ω. The value of the resistor is 100 Ω, and the inductive reactance is 100 Ω. What is the value of the capacitive reactance in the circuit?
A. 100 Ω
B. 10 Ω
C. 1000 Ω
D. 1 Ω
7. Look at the circuit that's shown in the figure. If the supply voltage of the circuit is 10 VAC RMS, using the value for total impedance given previously what is the total circuit current?
A. 1 A
B. 0.3 A
C. 0.033 A
D. 0.1 A
8. Look at the four circuit diagrams that are shown in the figure Which one of these four circuits has the lowest value of capacitive reactance?
A. Circuit 4
B. Circuit 2
C. Circuit 1
D. Circuit 3
9. Look at the circuit that's shown in the figure. Switch S2 is momentarily depressed and released to completely discharge capacitor C1 and capacitor C2. Switch S1 is then moved to the A position. The voltage across R1 will reach its maximum value
A. in 10 milliseconds.
B. only when the switch is moved back to the B position.
C. in 0.2 milliseconds.
D. as soon as the switch is closed in the A position.
10. Which of the following statements about capacitors is correct?
A. Capacitors in parallel add like resistors in parallel and inductors in parallel.
B. Capacitors in series add like resistors in series and inductors in series.
C. Capacitors in series add like resistors in parallel and inductors in series.
D. Capacitors in parallel add like resistors in series and inductors in series.
11. Look at the circuit that's shown in the figure. When switch S1 is moved to the B position, how long will it take for the voltage across R1 to reach its maximum value?
A. 10 milliseconds
B. 50 microseconds
C. 100 microseconds
D. 5 milliseconds
12. Look at the circuit shown in the figure. In this circuit, 100 VAC is applied to the primary of transformer T1. The turns ratio of T1 is 1:2 and you measure a voltage of 50 V at points C and D. Based on this information, what must be the turns ratio between the primary and secondary 1 of T2?
A. 1:1
B. 4:1
C. 1:2
D. 1:4
13. Look at the circuit shown in the figure. Suppose that you measured a voltage of 400 V across points E and F. Based on this reading, what must be the turns ratio between the primary and secondary 2 of T2?
A. 4:1
B. 2:1
C. 1:4
D. 1:2
14. Look at the circuit that's shown in the figure. If the value of the resistor was increased to 1,000 n, the total impedance of the circuit would
A. increase, because the circuit isn't resonant.
B. be unaffected, since the frequency of the AC source didn't change.
C. be unaffected, since the values of C and L didn't change.
D. increase, because the total impedance of the circuit is equal to R.
15. Look at the four circuit diagrams that are shown in the figure. Which of the four circuits has the highest impedance value?
A. Circuit 4
B. Circuit 2
C. Circuit 1
D. Circuit 3
16. Compared to a single-phase alternator, a three-phase alternator will generate
A. three sine waves delta-connected.
B. a higher output voltage.
C. three sine waves 120 degrees displaced.
D. a higher output current.
17. Look at the circuit diagram shown in the figure. Assuming that switches SP S2' and 53 are all closed, which of the following statements is correct?
A. Resistor R1 will reach the highest temperature.
B. All three resistors will reach approximately the same temperature.
C. Resistor R2 will reach the highest temperature.
D. Resistor R3 will reach the highest temperature.
18. A parallel LC circuit is found to be resonant at 100 kHz. If you rearranged the circuit so that the inductor and the capacitor were connected in series, the impedance would be
A. decreased and the resonant frequency would be unchanged.
B. increased and the resonant frequency would be unchanged.
C. decreased and the resonant frequency would be changed.
D. increased and the resonant frequency would be changed.
19. Look at the circuit that's shown in the figure. What is the power factor of the circuit?
A. 1
B. 100
C. 1,000
D. 10
20. Look at the circuit diagram shown in the figure. An ammeter is being used to measure the current in the primary winding. The ammeter displays a reading of 2 A. Based on this ammeter reading, which of the following statements about the switch positions is correct?
A. Only switch S3 is closed.
B. Switch S1 and switch S2 are both closed.
C. All three of the switches are closed.
D. Only switch S1 is closed.