MCQOPTIONS
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MCQOPTIONS
This section includes 24 Mcqs, each offering curated multiple-choice questions to sharpen your Alternating Current and Voltage knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A resistor and a capacitor are in series across a 20 V ac source. Circuit impedance is 4.33 k ohm. Current flow in the circuit is |
| A. | 92 mA |
| B. | 9.2 mA |
| C. | 460 mA |
| D. | 4.6 mA |
| Answer» E. | |
| 2. |
A 47 ohm resistor and a capacitor with a capacitive reactance of 120 ohm are in series across an ac source. What is the circuit impedance, Z? |
| A. | 12.9 ohm |
| B. | 129 ohm |
| C. | 73 ohm |
| D. | 167 ohm |
| Answer» C. 73 ohm | |
| 3. |
In the complex plane, the number 4 j3 is located in the |
| A. | second quadrant |
| B. | first quadrant |
| C. | fourth quadrant |
| D. | third quadrant |
| Answer» C. fourth quadrant | |
| 4. |
Point 4 on the complex plane is |
| A. | 4 units below the origin on the j axis |
| B. | 4 units right of the origin on the real axis |
| C. | 4 units left of the origin on the real axis |
| D. | 4 units above the origin on the j axis |
| Answer» C. 4 units left of the origin on the real axis | |
| 5. |
If the maximum value of a current of a circuit is 1 Amp (sinusoidal wave), what is the R.M.S value.... |
| A. | 1Amp |
| B. | 0.707 Amp |
| C. | 1.5Amp |
| D. | 0.636Amp |
| Answer» C. 1.5Amp | |
| 6. |
A 2 k ohm resistor is in series with a 0.015 F capacitor across a 15 kHz ac source. What is the magnitude of the total impedance and the phase angle? |
| A. | 707 ohm and θ = –19.5° |
| B. | 73.4 ohm and θ = –19.5° |
| C. | 734 ohm and θ = –38.9° |
| D. | 2121 ohm and θ = –19.5° |
| Answer» E. | |
| 7. |
A 47 resistor and a capacitor with 150 of capacitive reactance are in series across an ac source. The impedance, expressed in rectangular form, is |
| A. | Z = 47 + j 150 |
| B. | Z = 47 – j 150 |
| C. | Z = 197 |
| D. | Z = 103 |
| Answer» C. Z = 197 | |
| 8. |
When the frequency of the voltage applied to a series RC circuit is decreased, the impedance |
| A. | increases |
| B. | decreases |
| C. | remains the same |
| D. | doubles |
| Answer» B. decreases | |
| 9. |
A capacitor with 150 of capacitive reactance is across an ac source. The impedance, expressed in polar form, is |
| A. | Z = 150 |
| B. | Z = 150 90° |
| C. | Z = 150 –90° |
| D. | Z = 150 180° |
| Answer» D. Z = 150 180° | |
| 10. |
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 | |
| 11. |
The complex number 40 55° is equivalent to |
| A. | 55 + j 55 |
| B. | 40 + j 40 |
| C. | 45.88 + j 65.52 |
| D. | 22.94 + j 32.76 |
| Answer» E. | |
| 12. |
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 I = 0.3 0° 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. | |
| 13. |
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 | |
| 14. |
What is the angular difference between + j 4 and – j 4? |
| A. | 30° |
| B. | 90° |
| C. | 180° |
| D. | 270° |
| Answer» D. 270° | |
| 15. |
An ac circuit consists of a resistor and a capacitor. To increase the phase angle above 45°, the following condition must exist: |
| A. | R = X C |
| B. | R > X C |
| C. | R < X C |
| D. | R = 5 X C |
| Answer» D. R = 5 X C | |
| 16. |
In a parallel RC 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. | |
| 17. |
The complex number 6 + j 6 is equivalent to |
| A. | 6 45° |
| B. | 36 45° |
| C. | 8.48 45° |
| D. | 8.48 90° |
| Answer» D. 8.48 90° | |
| 18. |
A 47 resistor and a capacitor with a capacitive reactance of 120 are in series across an ac source. What is the circuit impedance, Z ? |
| A. | 129 |
| B. | 12.9 |
| C. | 167 |
| D. | 73 |
| Answer» B. 12.9 | |
| 19. |
When the frequency of the source voltage decreases, the impedance of a parallel RC circuit |
| A. | increases |
| B. | decreases |
| C. | does not change |
| D. | decreases to zero |
| Answer» B. decreases | |
| 20. |
In the complex plane, the number 4 + j 3 is located in the |
| A. | first quadrant |
| B. | second quadrant |
| C. | third quadrant |
| D. | fourth quadrant |
| Answer» B. second quadrant | |
| 21. |
In a series RC circuit, 12 V (rms) is measured across the resistor and 15 V (rms) 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 | |
| 22. |
A positive angle of 30° is equivalent to a negative angle of |
| A. | –30° |
| B. | –330° |
| C. | –60° |
| D. | –180° |
| Answer» C. –60° | |
| 23. |
A 470 resistor and a 0.2 F capacitor are in parallel across a 2.5 kHz ac source. The admittance, Y , in rectangular form, is |
| A. | 212 |
| B. | 2.12 mS + j 3.14 mS |
| C. | 3.14 mS + j 2.12 mS |
| D. | 318.3 |
| Answer» C. 3.14 mS + j 2.12 mS | |
| 24. |
In the complex plane, the number 14 – j 5 is located in the |
| A. | first quadrant |
| B. | second quadrant |
| C. | third quadrant |
| D. | fourth quadrant |
| Answer» E. | |