MCQOPTIONS
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MCQOPTIONS
This section includes 151 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
X = 2fL |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2. |
For inductions in series, L = L + L + L +... |
| A. | True |
| B. | False |
| Answer» B. False | |
| 3. |
What is the impedance of a 1 kHz series RL circuit when R and X are both 1000 ohms? |
| A. | 500 ohms |
| B. | 1000 ohms |
| C. | 1414 ohms |
| D. | 2000 ohms |
| Answer» D. 2000 ohms | |
| 4. |
You could decrease the time constant of an circuit by |
| A. | adding a resistor in parallel with the circuit resistance |
| B. | adding an inductor in series with the circuit inductance |
| C. | decreasing the amplitude of the input voltage |
| D. | exchanging the position of the resistor and inductor in the circuit |
| Answer» C. decreasing the amplitude of the input voltage | |
| 5. |
What is the inductive reactance if the of a coil is 60, and the winding resistance is 5 ? |
| A. | 0.083 |
| B. | 12 |
| C. | 30 |
| D. | 300 |
| Answer» E. | |
| 6. |
What is the current rise after 2 time constants if = 12 V dc, = 60 , and the inductor is rated at 24 mH? |
| A. | 79.9 mA |
| B. | 126.4 mA |
| C. | 173.0 mA |
| D. | 198.6 mA |
| Answer» D. 198.6 mA | |
| 7. |
What is the phase angle between the source voltage and current, when a 100 mH inductor with a reactance of 6 k, and a 1 k resistor are in series with a source? |
| A. | 0.1 degrees |
| B. | 9.0 degrees |
| C. | 61.0 degrees |
| D. | 81.0 degrees |
| Answer» E. | |
| 8. |
With 100 V applied to the primary of a transformer so that it draws 500 mA, what will be the 300 V secondary current? |
| A. | 1500 mA |
| B. | 200 mA |
| C. | 167 mA |
| D. | 150 mA |
| Answer» D. 150 mA | |
| 9. |
If 360 V is the output of a 300-turn secondary winding, what is the input voltage when the primary winding has 150 turns? |
| A. | 2.4 V |
| B. | 150 V |
| C. | 180 V |
| D. | 720 V |
| Answer» D. 720 V | |
| 10. |
A 24 V peak source is connected across a 900 H inductor. If the frequency of the source is 22 kHz, what is the reactive power? |
| A. | 2.3 VAR |
| B. | 4.6 VAR |
| C. | 9.3 VAR |
| D. | 0 VAR |
| Answer» B. 4.6 VAR | |
| 11. |
What is the number of turns required in the secondary winding for a transformer when 120 volts is applied to a 2400-turn primary to produce 7.5 V at the secondary? |
| A. | 75 turns |
| B. | 150 turns |
| C. | 900 turns |
| D. | 1920 turns |
| Answer» C. 900 turns | |
| 12. |
What is the phase angle of a 24 V parallel RL circuit when R = 45 ohms and X = 1100 ohms? |
| A. | 0.001 degrees |
| B. | 2.300 degrees |
| C. | 87.600 degrees |
| D. | 89.900 degrees |
| Answer» C. 87.600 degrees | |
| 13. |
The term choke is more commonly used in connection with an inductor used to block off high frequencies. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 14. |
Two inductors, L1 and L2, are in parallel. L1 has a value of 25 H and L2 a value of 50 H. The parallel combination is in series with L3, a 20 H coil. The entire combination is across an ac source of 60 Vrms at 300 kHz. The total rms current is |
| A. | 87 mA |
| B. | 870 mA |
| C. | 87 A |
| D. | 337 mA |
| Answer» C. 87 A | |
| 15. |
Inductors are not as versatile as capacitors. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 16. |
All the schematic symbols shown in the given figure are variable inductors. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 17. |
The output of the secondary winding is 15 V. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 18. |
Inductance is proportional to the cross-sectional area of a coil. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 19. |
Increasing the inductance value in an ac inductive circuit will lower the circuit current. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 20. |
An RL integrator can act as a __________ filter and an RC differentiator can act as a __________ filter. |
| A. | high-pass, high-pass |
| B. | low-pass, low-pass |
| C. | high-pass, low pass |
| D. | low-pass, high-pass |
| Answer» E. | |
| 21. |
A magnetic field results whenever a current flows through a conductor. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 22. |
A transformer can be designed to step up or step down dc voltage. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 23. |
An ac generator will produce a constant waveform. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 24. |
The inductance value of L3 in the given figure is _____ if the total inductance is 340 mH. |
| A. | 150 mH |
| B. | 220 mH |
| C. | 295 mH |
| D. | 315 mH |
| Answer» B. 220 mH | |
| 25. |
Faraday's law states that the polarity of induced voltage in a coil is in opposition to the current change through that coil. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 26. |
The opposition to ac by an inductor is directly proportional to ___. |
| A. | resistance |
| B. | reactance |
| C. | frequency |
| D. | voltage |
| Answer» D. voltage | |
| 27. |
In a dc circuit, the only conversion of energy to heat is in the inductance of the coil itself. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 28. |
When current flow tries to decrease in an inductor, the magnetic field _______________ and the voltage polarity across the inductor _______________. |
| A. | collapses, remains the same |
| B. | expands, reverses |
| C. | collapses, reverses |
| D. | expands, remains the same |
| Answer» D. expands, remains the same | |
| 29. |
Five time constants are required for current in an inductor to reach a maximum value. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 30. |
Lenz's law states that the current induced in a circuit due to a change in the magnetic field is so directed as to oppose the change in flux or to exert a mechanical force opposing the motion. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 31. |
Inductive ___ represents the opposition to an alternating current. |
| A. | impedance |
| B. | resistance |
| C. | reluctance |
| D. | reactance |
| Answer» E. | |
| 32. |
The primary and secondary are in phase. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 33. |
The secondary current in a transformer depends on the secondary voltage and load resistance values. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 34. |
The quality factor of an inductor is the ratio of inductive reactance to the winding resistance of the coil. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 35. |
The current through an inductor in a parallel RL circuit leads the current through the resistor. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 36. |
Magnetic force is the force that produces a magnetic field. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 37. |
Electromagnetic induction is the generation of _________ from __________. |
| A. | magnetism, electricity |
| B. | electricity, electricity |
| C. | electricity, magnetism |
| D. | magnetism, magnetism |
| Answer» D. magnetism, magnetism | |
| 38. |
Inductors connected in series will increase the total inductance value. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 39. |
For inductions in series, LT = L1 + L2 + L3 +... |
| A. | 1 |
| B. | |
| Answer» B. | |
| 40. |
Kirchhoff's voltage law does not apply to series RL circuits. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 41. |
A magnet consisting of a coil of wire wound around a soft iron or steel core is called an electromagnet. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 42. |
Self-inductance is the property that causes an electromotive force to be produced in a conductor. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 43. |
In a B-H curve, magnetizing force is equal to: |
| A. | |
| B. | H = I √ó N |
| C. | ampere-turns per weber |
| Answer» B. H = I √ó N | |
| 44. |
A winding of wire can be called |
| A. | an inductor |
| B. | a coil |
| C. | a choke |
| D. | All of the above |
| Answer» E. | |
| 45. |
Electromagnetism is the: |
| A. | magnetic field caused by a permanent magnet |
| B. | action between a permanent and an artificial magnet |
| C. | magnetic field action with a current-carrying wire |
| D. | current in the coil |
| Answer» D. current in the coil | |
| 46. |
An inductor is in series with a voltage source, an open switch, and a resistor. The instant the switch is closed, the inductor acts like |
| A. | a short |
| B. | an open |
| C. | a resistor |
| D. | a voltage source |
| Answer» C. a resistor | |
| 47. |
___ power represents the energy dissipated at a given point in time. |
| A. | 1 |
| B. | Reactive |
| C. | Real |
| D. | Instantaneous |
| Answer» E. | |
| 48. |
A magnetic field has: |
| A. | polar fields |
| B. | lines of force |
| C. | magnetomotive force |
| D. | lines of reluctance |
| Answer» C. magnetomotive force | |
| 49. |
When a rate of one ampere per second causes an induced voltage of one volt, the unit of measure is |
| A. | a lenz |
| B. | an ohm |
| C. | a farad |
| D. | a henry |
| Answer» E. | |
| 50. |
XL = 2fL |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |