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This section includes 217 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics knowledge and support exam preparation. Choose a topic below to get started.
1. |
What is the color code for a 220 5% resistor? |
A. | Red, Red, Brown, Gold |
B. | Orange, Orange, Black, Gold |
C. | Red, Red, Black, Gold |
D. | Red, Red, Brown, Silver |
Answer» B. Orange, Orange, Black, Gold | |
2. |
Which unit of charge contains 6.25 × 10electrons? |
A. | An ampere |
B. | A coulomb |
C. | A volt |
D. | A joule |
Answer» C. A volt | |
3. |
The symbol that represents electrical charge is . |
A. | True |
B. | False |
Answer» B. False | |
4. |
A resistor color coded with brown, black, and orange bands has a value of 10 k. |
A. | True |
B. | False |
Answer» B. False | |
5. |
A normally open push-buttonswitch can carry current when not pushed. |
A. | True |
B. | False |
Answer» C. | |
6. |
The battery symbol is: |
A. | [A]. |
B. | [B]. |
C. | [C]. |
D. | [D]. |
Answer» C. [C]. | |
7. |
Which unit of charge contains 6.25 × 1018 electrons? |
A. | An ampere |
B. | A coulomb |
C. | A volt |
D. | A joule |
Answer» C. A volt | |
8. |
When one sine wave passes through the zero following the other, it is _________ |
A. | Leading |
B. | Lagging |
C. | Neither leading nor lagging |
D. | Either leading or lagging |
Answer» C. Neither leading nor lagging | |
9. |
A phasor has frozen at 30 degrees, find the value of the phase angle. |
A. | 30 degrees |
B. | 60 degrees |
C. | 120 degrees |
D. | 180 degrees |
Answer» B. 60 degrees | |
10. |
The rms value is _________ times the maximum value. |
A. | 1.414 |
B. | 0.5 |
C. | 2 |
D. | 0.707 |
Answer» E. | |
11. |
Ammeters and voltmeters are calibrated to read? |
A. | RMS value |
B. | Peak value |
C. | Average value |
D. | Instantaneous value |
Answer» B. Peak value | |
12. |
Usually phasor diagrams are drawn representing? |
A. | RMS value |
B. | Peak value |
C. | Average value |
D. | Instantaneous value |
Answer» B. Peak value | |
13. |
The instantaneous values of two alternating voltages are given as:v1=60sinθ and v2=40sin(θ − π/3).Find the instantaneous difference. |
A. | 53 sin(71.5°) V |
B. | 53 sin( 79..5°) V |
C. | 53 sin(26.5°) V |
D. | 53 cos(36.5°) V |
Answer» C. 53 sin(26.5°) V | |
14. |
The rms value is 0.707 times the _________ value. |
A. | Peak |
B. | Instantaneous |
C. | Average |
D. | DC |
Answer» B. Instantaneous | |
15. |
The time axis of an AC phasor represents? |
A. | Time |
B. | Phase angle |
C. | Voltage |
D. | Current |
Answer» C. Voltage | |
16. |
The instantaneous values of two alternating voltages are given as:v1=60sinθ and v2=40sin(θ − π/3). Find the instantaneous sum. |
A. | 87.2 sin(36.5°) V |
B. | 87.2 sin( 0.5°) V |
C. | 87.2 sin(26.5°) V |
D. | 87.2 cos(36.5°) V |
Answer» B. 87.2 sin( 0.5°) V | |
17. |
For addition and subtraction of phasors, we use the _________ form. |
A. | Rectangular |
B. | Polar |
C. | Either rectangular or polar |
D. | Neither rectangular nor polar |
Answer» B. Polar | |
18. |
What is the correct expression of ω? |
A. | ω=2π |
B. | ω=2πf |
C. | ω=πf |
D. | ω=2f² |
Answer» C. ω=πf | |
19. |
The length of the phasor represents? |
A. | Magnitude of the quantity |
B. | Direction of the quantity |
C. | Neither magnitude nor direction |
D. | Either magnitude or direction |
Answer» B. Direction of the quantity | |
20. |
Find the value of ω if the frequency is 5Hz? |
A. | 3.14 rad/s |
B. | 31.4 rad/s |
C. | 34 rad/s |
D. | 341 rad/s |
Answer» C. 34 rad/s | |
21. |
If two current phasors, having magnitude 12A and 5A intersect at an angle of 90 degrees, calculate the resultant current. |
A. | 13 A |
B. | 10 A |
C. | 6 A |
D. | 5 A |
Answer» B. 10 A | |
22. |
If the phasors are drawn to represent the maximum values instead of the rms values, what would happen to the phase angle between quantities? |
A. | Increases |
B. | Decreases |
C. | Remains constant |
D. | Becomes zero |
Answer» D. Becomes zero | |
23. |
If two current phasors, having magnitude 5A and 10A intersect at an angle of 60 degrees, calculate the resultant current. |
A. | 12.23 A |
B. | 12.54 A |
C. | 13.23 A |
D. | 14.24 A |
Answer» D. 14.24 A | |
24. |
For multiplication and division of phasors, we use ____________ form. |
A. | Rectangular |
B. | Polar |
C. | Either rectangular or polar |
D. | Neither rectangular nor polar |
Answer» C. Either rectangular or polar | |
25. |
If the maximum value of the current is 5√2 A, what will be the value of the average current? |
A. | 10/π A |
B. | 5/π A |
C. | 15/π A |
D. | 25/π A |
Answer» B. 5/π A | |
26. |
Find the total current in the circuit if two currents of 4+5j flow in the circuit. |
A. | 4+5j A |
B. | 4A |
C. | 5A |
D. | 8+10j A |
Answer» E. | |
27. |
If a voltage of 2+5j and another voltage of 3+ 6j flows through two different resistors, connected in series, in a circuit, find the total voltage in the circuit. |
A. | 2+5j V |
B. | 3+6j V |
C. | 5+11j V |
D. | 5+10j V |
Answer» D. 5+10j V | |
28. |
Calculate the number of revolutions if the frequency is 15kHz and the paired poles are 50. |
A. | 100 |
B. | 200 |
C. | 300 |
D. | 400 |
Answer» D. 400 | |
29. |
Calculate the frequency if the number of revolutions is 300 and the paired poles are 50. |
A. | 15kHz |
B. | 150kHz |
C. | 1500kHz |
D. | 150Hz |
Answer» B. 150kHz | |
30. |
What is the frequency of a two pole machine having n=50? |
A. | 100Hz |
B. | 200Hz |
C. | 50Hz |
D. | 25Hz |
Answer» D. 25Hz | |
31. |
What happens to the frequency if the number of pairs of poles increases? |
A. | Increases |
B. | Decreases |
C. | Remains the same |
D. | Becomes zero |
Answer» B. Decreases | |
32. |
Calculate the number of paired poles if the frequency id 15kHz and the number of revolutions is 300. |
A. | 10 |
B. | 30 |
C. | 50 |
D. | 70 |
Answer» D. 70 | |
33. |
For a rectangular wave, average current is ______ rms current. |
A. | Greater than |
B. | Less than |
C. | Equal to |
D. | Not related |
Answer» D. Not related | |
34. |
In a sinusoidal wave, average current is always _______ rms current. |
A. | Greater than |
B. | Less than |
C. | Equal to |
D. | Not related |
Answer» C. Equal to | |
35. |
__________ current is found by dividing the area enclosed by the half cycle by the length of the base of the half cycle. |
A. | RMS current |
B. | Average current |
C. | Instantaneous current |
D. | Total current |
Answer» C. Instantaneous current | |
36. |
What is the effective value of current? |
A. | RMS current |
B. | Average current |
C. | Instantaneous current |
D. | Total current |
Answer» B. Average current | |
37. |
Peak value divided by the rms value gives us? |
A. | Peak factor |
B. | Crest factor |
C. | Both peak and crest factor |
D. | Neither peak nor crest factor |
Answer» D. Neither peak nor crest factor | |
38. |
Which is the correct formula for frequency in an ac generator? |
A. | f=p*n |
B. | f=p/n |
C. | f=n/p |
D. | f=n²p |
Answer» B. f=p/n | |
39. |
When is the shape of the negative half of the emf waveform equal to the positive half? |
A. | When the conductors move past north pole |
B. | When conductors move past south pole |
C. | When conductors move past both north and south pole |
D. | When conductors are stationary |
Answer» D. When conductors are stationary | |
40. |
The waveform of the emf generated undergoes one complete cycle when? |
A. | Conductors move past north pole |
B. | Conductors move past south pole |
C. | Conductors move past north and south poles |
D. | Conductors are stationary |
Answer» D. Conductors are stationary | |
41. |
If the peak voltage is 9V, calculate the peak to peak voltage. |
A. | 9V |
B. | 20V |
C. | 18V |
D. | 12V |
Answer» D. 12V | |
42. |
What is the minimum number of poles that a machine must have __________ |
A. | 1 |
B. | 2 |
C. | 4 |
D. | 10 |
Answer» C. 4 | |
43. |
What is the type of current obtained by finding the square of the currents and then finding their average and then fining the square root? |
A. | RMS current |
B. | Average current |
C. | Instantaneous current |
D. | Total current |
Answer» B. Average current | |
44. |
What will happen to the frequency if the number of revolutions increases? |
A. | Increases |
B. | Decreases |
C. | Remains the same |
D. | Becomes zero |
Answer» B. Decreases | |
45. |
What is the current found by finding the current in an equidistant region and dividing by n? |
A. | RMS current |
B. | Average current |
C. | Instantaneous current |
D. | Total current |
Answer» C. Instantaneous current | |
46. |
RMS stands for ________ |
A. | Root Mean Square |
B. | Root Mean Sum |
C. | Root Maximum sum |
D. | Root Minimum Sum |
Answer» B. Root Mean Sum | |
47. |
Find the average value of current when the current that are equidistant are 4A, 5A and 6A. |
A. | 5A |
B. | 6A |
C. | 15A |
D. | 10A |
Answer» B. 6A | |
48. |
The resultant of two alternating sinusoidal voltages or currents can be found using ___________ |
A. | Triangular law |
B. | Parallelogram law |
C. | Either triangular or parallelogram law |
D. | Neither triangular nor parallelogram law |
Answer» C. Either triangular or parallelogram law | |
49. |
If maximum value of current is 5√2 A, what will be the value of RMS current? |
A. | 10 A |
B. | 5 A |
C. | 15 A |
D. | 25 A |
Answer» C. 15 A | |
50. |
Calculate the crest factor if the peak value of current is 10A and the rms value is 2A. |
A. | 5 |
B. | 10 |
C. | 5A |
D. | 10A |
Answer» B. 10 | |