MCQOPTIONS
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MCQOPTIONS
This section includes 73 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A 120 resistor is in parallel with a capacitor with a capacitive reactance of 40 . Both components are across a 12 V ac source. What is the magnitude of the total impedance? |
| A. | 37.9 |
| B. | 3.7 |
| C. | 14,400 |
| D. | 4,800 |
| Answer» B. 3.7 | |
| 2. |
A 2 k resistor and a 0.002 F capacitor are in series across an ac source. Current in the circuit is 6.50 mA. The true power is |
| A. | 84.5 mW |
| B. | 845 mW |
| C. | 13 mW |
| D. | 130 mW |
| Answer» B. 845 mW | |
| 3. |
A 12 k resistor is in series with a 0.02 F capacitor across a 1.2 kHz ac source. If the current is expressed in polar form as = 0.30° mA, what is the source voltage expressed in polar form? |
| A. | 45.6 V |
| B. | 411.3 V |
| C. | 0.411 V |
| D. | 4.11 V |
| Answer» E. | |
| 4. |
In a series circuit, when the frequency and the resistance are halved, the impedance |
| A. | doubles |
| B. | is halved |
| C. | is reduced to one-fourth |
| D. | cannot be determined without values |
| Answer» E. | |
| 5. |
A resistor and a capacitor are in series across a 20 V ac source. Circuit impedance is 4.33 k. Current flow in the circuit is |
| A. | 9.2 mA |
| B. | 92 mA |
| C. | 4.6 mA |
| D. | 460 mA |
| Answer» D. 460 mA | |
| 6. |
In a parallel circuit, there is 100 mA through the resistive branch and 100 mA through the capacitive branch. The total rms current is |
| A. | 200 mA |
| B. | 100 mA |
| C. | 282 mA |
| D. | 141 mA |
| Answer» E. | |
| 7. |
What is the angular difference between +4 and –4? |
| A. | 30° |
| B. | 90° |
| C. | 180° |
| D. | 270° |
| Answer» D. 270° | |
| 8. |
In the complex plane, the number 4 + 3 is located in the |
| A. | first quadrant |
| B. | second quadrant |
| C. | third quadrant |
| D. | fourth quadrant |
| Answer» B. second quadrant | |
| 9. |
When the frequency of the source voltage decreases, the impedance of a parallel circuit |
| A. | increases |
| B. | decreases |
| C. | does not change |
| D. | decreases to zero |
| Answer» B. decreases | |
| 10. |
A 47 resistor and a capacitor with a capacitive reactance of 120 are in series across an ac source. What is the circuit impedance, ? |
| A. | 129 |
| B. | 12.9 |
| C. | 167 |
| D. | 73 |
| Answer» B. 12.9 | |
| 11. |
A 6 kHz sinusoidal voltage is applied to a series circuit. The frequency of the voltage across the resistor is |
| A. | 0 Hz |
| B. | 12 kHz |
| C. | 6 kHz |
| D. | 18 kHz |
| Answer» D. 18 kHz | |
| 12. |
In a series circuit, 12 V is measured across the resistor and 15 V is measured across the capacitor. The rms source voltage is |
| A. | 3 V |
| B. | 27 V |
| C. | 19.2 V |
| D. | 1.9 V |
| Answer» D. 1.9 V | |
| 13. |
The power factor () indicates how much of the apparent power is true power. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 14. |
Total current in an circuit always leads the source voltage. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 15. |
The impedance of a series circuit varies directly with frequency. |
| A. | True |
| B. | False |
| Answer» C. | |
| 16. |
In an circuit, the impedance is determined by both the resistance and the capacitive reactance combined. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 17. |
In the complex plane, the number 14 – 5 is located in the |
| A. | first quadrant |
| B. | second quadrant |
| C. | third quadrant |
| D. | fourth quadrant |
| Answer» E. | |
| 18. |
Referring to Problem 21, what is the phase angle for the circuit? |
| A. | 7.1° |
| B. | 71.5° |
| C. | 1.8° |
| D. | 18.4° |
| Answer» E. | |
| 19. |
The polar form of a complex number consists of a real part and a part. |
| A. | True |
| B. | False |
| Answer» C. | |
| 20. |
In a lag network, the output voltage lags the input voltage in phase. |
| A. | rue |
| B. | alse |
| Answer» B. alse | |
| 21. |
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. | 7.9 Ω |
| B. | .7 Ω |
| C. | 4,400 Ω |
| D. | ,800 Ω |
| Answer» B. .7 Ω | |
| 22. |
Positive numbers can be represented by points to the right of the origin on the horizontal axis of a graph. |
| A. | rue |
| B. | alse |
| Answer» B. alse | |
| 23. |
A filter passes all frequencies. |
| A. | rue |
| B. | alse |
| Answer» C. | |
| 24. |
The resistor voltage is always out of phase with the current. |
| A. | rue |
| B. | alse |
| Answer» C. | |
| 25. |
A 470 Ω resistor and a 0.2 µF capacitor are in parallel across a 2.5 kHz ac source. The admittance, Y, in rectangular form, is |
| A. | 12 Ω |
| B. | .12 mS + j3.14 mS |
| C. | .14 mS + j2.12 mS |
| D. | 18.3 Ω |
| Answer» C. .14 mS + j2.12 mS | |
| 26. |
A 47 Ω resistor and a capacitor with 150 Ω of capacitive reactance are in series across an ac source. The impedance, expressed in rectangular form, is |
| A. | = 47 Ω + j150 Ω |
| B. | = 47 Ω - j150 Ω |
| C. | = 197 Ω |
| D. | = 103 Ω |
| Answer» C. = 197 Ω | |
| 27. |
A resistor and a capacitor are in series across a 20 V ac source. Circuit impedance is 4.33 kΩ. Current flow in the circuit is |
| A. | .2 mA |
| B. | 2 mA |
| C. | .6 mA |
| D. | 60 mA |
| Answer» D. 60 mA | |
| 28. |
The polar form of a complex number consists of a real part and a j part. |
| A. | rue |
| B. | alse |
| Answer» C. | |
| 29. |
In the complex plane, the number 14 - j5 is located in the |
| A. | irst quadrant |
| B. | econd quadrant |
| C. | hird quadrant |
| D. | ourth quadrant |
| Answer» E. | |
| 30. |
A 47 Ω resistor and a capacitor with a capacitive reactance of 120 Ω are in series across an ac source. What is the circuit impedance, Z? |
| A. | 29 Ω |
| B. | 2.9 Ω |
| C. | 67 Ω |
| D. | 3 Ω |
| Answer» B. 2.9 Ω | |
| 31. |
An imaginary number is one that exists only in the mind of the mathematician. |
| A. | rue |
| B. | alse |
| Answer» C. | |
| 32. |
A 12 kΩ resistor is in series with a 0.02 µF capacitor across a 1.2 kHz ac source. If the current is expressed in polar form as I = 0.3 ∠0° mA, what is the source voltage expressed in polar form? |
| A. | 5.6 V |
| B. | 11.3 V |
| C. | .411 V |
| D. | .11 V |
| Answer» E. | |
| 33. |
A capacitor with 150 Ω of capacitive reactance is across an ac source. The impedance, expressed in polar form, is |
| A. | = 150 |
| B. | = 150 ∠90°O |
| C. | = 150 ∠-90°O |
| D. | = 150 ∠180°O |
| Answer» D. = 150 ∠180°O | |
| 34. |
The circuit phase angle is the angle between the total current and the applied (source) voltage. |
| A. | rue |
| B. | alse |
| Answer» B. alse | |
| 35. |
The impedance of a series RC circuit varies directly with frequency. |
| A. | rue |
| B. | alse |
| Answer» C. | |
| 36. |
What is the angular difference between +j4 and -j4? |
| A. | 0° |
| B. | 0° |
| C. | 80° |
| D. | 70° |
| Answer» D. 70° | |
| 37. |
A 2 kΩ resistor is in series with a 0.015 µF capacitor across a 15 kHz ac source. What is the magnitude of the total impedance and the phase angle? |
| A. | 3.4 Ω and ∠ = -19.5° |
| B. | 07 Ω and ∠ = -19.5° |
| C. | 121 Ω and ∠ = -19.5° |
| D. | 34 Ω and ∠ = -38.9° |
| Answer» D. 34 Ω and ∠ = -38.9° | |
| 38. |
A 2 kΩ resistor and a 0.002 µF capacitor are in series across an ac source. Current in the circuit is 6.50 mA. The true power is |
| A. | 4.5 mW |
| B. | 45 mW |
| C. | 3 mW |
| D. | 30 mW |
| Answer» B. 45 mW | |
| 39. |
The complex number 40 ∠ 55° is equivalent to |
| A. | 5 + j55 |
| B. | 0 + j40 |
| C. | 5.88 + j65.52 |
| D. | 2.94 + j32.76 |
| Answer» E. | |
| 40. |
Total current in an RC circuit always leads the source voltage. |
| A. | rue |
| B. | alse |
| Answer» B. alse | |
| 41. |
In the complex plane, the number 14 - j5 is located in the Fourth quadrant |
| A. | rue |
| B. | alse |
| Answer» B. alse | |
| 42. |
The capacitor voltage always leads the current by 90°. |
| A. | rue |
| B. | alse |
| Answer» C. | |
| 43. |
The complex number 6 + j6 is equivalent to |
| A. | ∠45° |
| B. | 6 ∠45° |
| C. | .48 ∠45° |
| D. | .48 ∠90° |
| Answer» D. .48 ∠90° | |
| 44. |
Apparent power is expressed in watts. |
| A. | rue |
| B. | alse |
| Answer» C. | |
| 45. |
A positive angle of 30° is equivalent to a negative angle of |
| A. | 30° |
| B. | 330° |
| C. | 60° |
| D. | 180° |
| Answer» C. 60° | |
| 46. |
The complex number 40 55° is equivalent to |
| A. | 55 + j55 |
| B. | 40 + j40 |
| C. | 45.88 + j65.52 |
| D. | 22.94 + j32.76 |
| Answer» E. | |
| 47. |
Complex numbers can be added and subtracted but not multiplied or divided. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» C. 1 | |
| 48. |
For a certain load, the true power is 150 W and the reactive power is 125 VAR. The apparent power is |
| A. | 19.52 W |
| B. | 195.2 W |
| C. | 275 W |
| D. | 25 W |
| Answer» C. 275 W | |
| 49. |
Point +4 on the complex plane is |
| A. | 4 units above the origin on the j axis |
| B. | 4 units below the origin on the j axis |
| C. | 4 units right of the origin on the real axis |
| D. | 4 units left of the origin on the real axis |
| Answer» D. 4 units left of the origin on the real axis | |
| 50. |
An ac circuit consists of a resistor and a capacitor. To increase the phase angle above 45°, the following condition must exist: |
| A. | R = XC |
| B. | R > XC |
| C. | R < XC |
| D. | R = 5XC |
| Answer» D. R = 5XC | |