MCQOPTIONS
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MCQOPTIONS
This section includes 43 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The instantaneous voltage at 120° on a 5 V peak sine wave equals about –4.33 V. |
| A. | True |
| B. | False |
| Answer» C. | |
| 2. |
90° equals 1.57 radians. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 3. |
What is the instantaneous peak voltage at 250° on a 6 V peak sine wave? |
| A. | +5.64 V |
| B. | –5.64 V |
| C. | +26.13 V |
| D. | –26.13 V |
| Answer» C. +26.13 V | |
| 4. |
The sine of a given angle is equal to the ratio of the hypotenuse to the opposite side. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 5. |
10,000 cycles will occur in 5 s if a sine wave's frequency equals 2 kHz. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 6. |
If a sine wave's period equals 50 ms, its frequency equals _____. |
| A. | 20 Hz |
| B. | 0.02 Hz |
| C. | 50 Hz |
| D. | 50 kHz |
| Answer» B. 0.02 Hz | |
| 7. |
A sine wave has only one positive maximum point during a cycle. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 8. |
The phase angle between the two waveforms in the given circuit equals _____. |
| A. | 75° |
| B. | 15° |
| C. | 105° |
| D. | 45° |
| Answer» C. 105¬∞ | |
| 9. |
If a sine wave's frequency equals 25 MHz, its period equals _____. |
| A. | 25 µs |
| B. | 25 ms |
| C. | 4 µs |
| D. | 40 ns |
| Answer» E. | |
| 10. |
A peak current of 12.5 mA is equivalent to ___. |
| A. | an rms value of 25 mA |
| B. | an average value of 12.5 mA |
| C. | a peak-to-peak value of 6.25 mA |
| D. | an average value of 7.96 mA |
| Answer» E. | |
| 11. |
The rms voltage value is a measure of a sine wave's heating effect. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 12. |
The square, rectangular, and sawtooth waveforms are nonsymmetrical. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 13. |
An rms voltage of 5 V is equivalent to ___. |
| A. | 14.14 V peak-to-peak |
| B. | a peak value of 5 V |
| C. | 10 V peak-to-peak |
| D. | an average value of 7.07 V |
| Answer» B. a peak value of 5 V | |
| 14. |
A sine wave's peak-to-peak voltage value is always twice its peak voltage value. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 15. |
If you increase the rotational speed of the conductor in a basic generator, the frequency of the resulting sine wave voltage will increase. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 16. |
The frequency of the sine wave in the given circuit equals ___. |
| A. | 4 kHz |
| B. | 800 Hz |
| C. | 20 kHz |
| D. | 250 Hz |
| Answer» D. 250 Hz | |
| 17. |
A single-phase induction motor |
| A. | is self-starting |
| B. | operates at a fixed speed |
| C. | is less reliable than a three-phase synchronous motor |
| D. | none of the above |
| Answer» E. | |
| 18. |
What is the fourth harmonic of a fundamental frequency of 400 Hz? |
| A. | 100 Hz |
| B. | 4 kHz |
| C. | 4 Hz |
| D. | 1.6 kHz |
| Answer» E. | |
| 19. |
Increasing the number of turns in a conductor loop in a basic generator will ___. |
| A. | increase the generator's output voltage amplitude |
| B. | increase the generator's output frequency |
| C. | decrease the generator's output voltage amplitude |
| D. | decrease the generator's output frequency |
| Answer» B. increase the generator's output frequency | |
| 20. |
The peak voltage across R2 in the given circuit equals _____. |
| A. | 7.2 V |
| B. | 10.18 V |
| C. | 8.8 V |
| D. | 8 V |
| Answer» C. 8.8 V | |
| 21. |
The instantaneous voltage at 120° on a 5 V peak sine wave equals about –4.33 V. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» C. 1 | |
| 22. |
Which point is the trailing edge of the repetitive pulse waveform in the given circuit? |
| A. | Point A |
| B. | Point B |
| C. | Point C |
| D. | Point D |
| Answer» B. Point B | |
| 23. |
What is the peak voltage across R3 in the given circuit? |
| A. | 1.2 V |
| B. | 5 V |
| C. | 7 V |
| D. | 12 V |
| Answer» C. 7 V | |
| 24. |
90° equals 1.57 radians. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 25. |
A rectangular wave that has a duty cycle of 50% could be called a |
| A. | "c" wave |
| B. | sawtooth wave |
| C. | square wave |
| D. | triangular wave |
| Answer» D. triangular wave | |
| 26. |
Calculate the duty cycle of the repetitive pulse waveform in the given circuit. |
| A. | 0.0833 |
| B. | 0 |
| C. | 0.3333 |
| D. | 0.25 |
| Answer» E. | |
| 27. |
All periodic frequencies are derived by combining higher frequency ______________ called harmonics. |
| A. | sine waves |
| B. | pulse waves |
| C. | square waves |
| D. | sawtooth waves |
| Answer» B. pulse waves | |
| 28. |
Calculate the positive-going slope of the waveform in the given circuit. |
| A. | 5 V/ms |
| B. | 2.5 V/ms |
| C. | 2.5 V/s |
| D. | 5 V/s |
| Answer» C. 2.5 V/s | |
| 29. |
If a wave has frequency of 2 Hz, it has a period of ? |
| A. | 1s |
| B. | 1/2 s |
| C. | 2.5s |
| D. | 2s |
| Answer» C. 2.5s | |
| 30. |
The effective value of a sine wave is equal to |
| A. | 0.707 of peak voltage |
| B. | 0.636 of peak voltage |
| C. | sin 45° of peak voltage |
| D. | both 0.707 of peak voltage and sin 45° of peak voltage |
| Answer» E. | |
| 31. |
Increasing the number of magnetic poles in a basic generator will ___. |
| A. | increase the generator's output voltage amplitude |
| B. | increase the generator's output frequency |
| C. | decrease the generator's output voltage amplitude |
| D. | decrease the generator's output frequency |
| Answer» C. decrease the generator's output voltage amplitude | |
| 32. |
The magnitude of an alternation that varies from zero is called its _______. |
| A. | altitude |
| B. | polarity |
| C. | attitude |
| D. | amplitude |
| Answer» E. | |
| 33. |
A 1 Hz sine wave has a period of 1 s. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 34. |
A half-cycle average voltage of 12 V is equal to what rms voltage? |
| A. | 13.33 V |
| B. | 8.48 V |
| C. | 18.84 V |
| D. | 7.64 V |
| Answer» B. 8.48 V | |
| 35. |
The frequency of the repetitive pulse waveform in the given circuit equals ___. |
| A. | 500 Hz |
| B. | 50 Hz |
| C. | 100 Hz |
| D. | 125 Hz |
| Answer» D. 125 Hz | |
| 36. |
What is the average voltage when a rectangular wave's base line voltage is 20 V, its peak-to-peak voltage is 50 V, and its duty cycle is 20%? |
| A. | 26 V |
| B. | 30 V |
| C. | 40 V |
| D. | 45 V |
| Answer» C. 40 V | |
| 37. |
In both induction and synchronous ac motors |
| A. | the operating speed is very steady |
| B. | the stator magnetic field is stationary |
| C. | the stator magnetic field rotates |
| D. | the "squirrel cage" forms the rotor |
| Answer» D. the "squirrel cage" forms the rotor | |
| 38. |
What is the dc voltage of the waveform in the given circuit? |
| A. | 2 V |
| B. | 4 V |
| C. | 6 V |
| D. | 8 V |
| Answer» D. 8 V | |
| 39. |
One revolution of a conductor through the magnetic field of a basic generator will produce two complete sine waves. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» C. 1 | |
| 40. |
Most practical alternators generate electricity from |
| A. | a coil rotating within a magnetic field |
| B. | a magnetic field rotating around fixed windings |
| C. | a permanent magnet rotating within a varying electromagnetic field |
| D. | none of the above |
| Answer» C. a permanent magnet rotating within a varying electromagnetic field | |
| 41. |
What is the instantaneous peak voltage at 250° on a 6 V peak sine wave? |
| A. | +5.64 V |
| B. | –5.64 V |
| C. | +26.13 V |
| D. | –26.13 V |
| Answer» C. +26.13 V | |
| 42. |
What is the peak-to-peak voltage of the waveform in the given circuit? |
| A. | 2 V |
| B. | 4 V |
| C. | 6 V |
| D. | 8 V |
| Answer» E. | |
| 43. |
What type of waveform is shown in the given circuit? |
| A. | Sine wave |
| B. | Square wave |
| C. | Triangle wave |
| D. | Sawtooth wave |
| Answer» D. Sawtooth wave | |