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.
| 51. |
A change of one ampere per second in an inductor that induces a voltage of one volt is considered as which unit value? |
| A. | a lenz |
| B. | an ohm |
| C. | a farad |
| D. | a henry |
| Answer» E. | |
| 52. |
With 100 Vac applied to the primary of a transformer so that it draws 500 mA, what will be the 300 Vac secondary current? |
| A. | 1500 mA |
| B. | 200 mA |
| C. | 167 mA |
| D. | 150 mA |
| Answer» D. 150 mA | |
| 53. |
Inductance is: |
| A. | directly proportional to the length of the coil |
| B. | directly proportional to the number of turns on the coil |
| C. | inversely proportional to the cross-sectional area of the coil |
| D. | inversely proportional to the permeability |
| Answer» C. inversely proportional to the cross-sectional area of the coil | |
| 54. |
The amount of dc current that an inductor will allow to pass depends on the circuit's total resistance that is in series with it. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 55. |
The total inductive reactance is ___ in the given circuit. |
| A. | 3.5 k |
| B. | 4.4 k |
| C. | 16.3 k |
| D. | 23.3 k |
| Answer» E. | |
| 56. |
What term is used to describe the action of magnetic flux from one circuit that cuts across the conductors of another circuit? |
| A. | self-inductance |
| B. | rectification |
| C. | mutual inductance |
| D. | magnetism |
| Answer» D. magnetism | |
| 57. |
What is the total inductance of a 5 H and a 100 mH coil connected in parallel? |
| A. | 4.76 mH |
| B. | 33.3 mH |
| C. | 98.0 mH |
| D. | 150.0 mH |
| Answer» D. 150.0 mH | |
| 58. |
On a schematic, dashed lines between two vertical coils usually mean the transformer has: |
| A. | an air core |
| B. | an iron core |
| C. | a nonmetallic core |
| D. | a ferrite core |
| Answer» E. | |
| 59. |
What is the inductive reactance? |
| A. | 5.2 |
| B. | 7.5 |
| C. | 1.3 k |
| D. | 7.5 k |
| Answer» E. | |
| 60. |
What is the maximum source current for a transformer rated at 10 kVA, 1000/500 60 Hz? |
| A. | 0.083333333333333 |
| B. | 0.20833333333333 |
| C. | 0.41666666666667 |
| D. | 20 A |
| Answer» E. | |
| 61. |
What is the impedance of a 1 kHz series RL circuit when R and XL are both 1000 ohms? |
| A. | 500 ohms |
| B. | 1000 ohms |
| C. | 1414 ohms |
| D. | 2000 ohms |
| Answer» D. 2000 ohms | |
| 62. |
What does Faraday's law concern? |
| A. | a magnetic field in a coil |
| B. | a magnetic field cutting a conductor |
| C. | a magnetic field hystersis |
| D. | a magnetic field in a conductor |
| Answer» C. a magnetic field hystersis | |
| 63. |
A henry value divided by a circuit resistive value provides the: |
| A. | counter emf value |
| B. | induced voltage amplitude |
| C. | rise or decay time constant |
| D. | quality factor of the coil |
| Answer» C. rise or decay time constant | |
| 64. |
With a square wave input, an RL differentiator circuit with an output across the inductor will produce what type of waveform? |
| A. | dc |
| B. | short time-duration pulses |
| C. | exponential-shaped pulses |
| D. | only a phase shift |
| Answer» C. exponential-shaped pulses | |
| 65. |
An inductor will boost current flow. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 66. |
What is the total inductance in the given circuit? |
| A. | 160 mH |
| B. | 300 mH |
| C. | 900 mH |
| D. | 1700 mH |
| Answer» B. 300 mH | |
| 67. |
Find IR and IL. |
| A. | IR = 50 mA, IL = 109 mA |
| B. | IR = 150 mA, IL = 9 mA |
| C. | IR = 50 mA, IL = 151 mA |
| D. | IR = 150 mA, IL = 53 mA |
| Answer» E. | |
| 68. |
When used as a filter, an inductor is |
| A. | placed in series with the load and aids any current changes |
| B. | placed in parallel with the load and aids any current changes |
| C. | placed in parallel with the load and opposes any current changes |
| D. | placed in series with the load and opposes any current changes |
| Answer» E. | |
| 69. |
An ideal inductor would not dissipate any energy. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 70. |
The time constant of an inductive circuit is dependent on the circuit's resistance. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 71. |
After the first time constant, a transient current has changed by _______________ %, leaving _______________ % remaining. |
| A. | 63.2, 36.8 |
| B. | 36.8, 63.2 |
| C. | 13.5, 86.5 |
| D. | 86.5, 13.5 |
| Answer» B. 36.8, 63.2 | |
| 72. |
If 360 Vac is the output of a 300-turn secondary winding, what is the input voltage when the primary winding has 150 turns? |
| A. | 2.4 Vac |
| B. | 150 Vac |
| C. | 180 Vac |
| D. | 720 Vac |
| Answer» D. 720 Vac | |
| 73. |
What is the permeability of machine steel? |
| A. | 1.1 x 10‚àí4 |
| B. | 5.65 x 10‚àí4 |
| C. | 6.9 x 10‚àí3 |
| D. | 8.8 x 10‚àí3 |
| Answer» C. 6.9 x 10‚àí3 | |
| 74. |
A transformer will have: |
| A. | primary and secondary windings |
| B. | primary and secondary current |
| C. | primary wattage producing secondary current |
| D. | different frequencies for the primary and secondary |
| Answer» B. primary and secondary current | |
| 75. |
What is the name of the part inside a relay that is moved by the action of the electromagnet? |
| A. | armature |
| B. | conductor |
| C. | contacts |
| D. | solenoid |
| Answer» B. conductor | |
| 76. |
An RL filter could be a high-pass or a low-pass filter. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 77. |
The four factors determining inductance are the number of turns, coil length, coil area, and: |
| A. | permeability |
| B. | reluctance |
| C. | counter emf |
| D. | coefficient of coupling |
| Answer» B. reluctance | |
| 78. |
Current will cause a magnetic field in a conductor as follows: |
| A. | An ac current causes a fixed polarity magnetic field. |
| B. | A dc current causes a fixed polarity magnetic field. |
| C. | A dc current causes an alternating magnetic field. |
| D. | An ac current causes a fixed polarity magnetic field and a dc current causes an alternating magnetic field. |
| Answer» C. A dc current causes an alternating magnetic field. | |
| 79. |
When a coil collapses the induced circuit current will: |
| A. | be in the same direction |
| B. | go to zero |
| C. | aid counter emf buildup |
| D. | be in the opposite direction |
| Answer» B. go to zero | |
| 80. |
Indication of transformer primary and secondary voltage relationships is accomplished by: |
| A. | color-coded wires |
| B. | dot notation |
| C. | black, rather than gray, casings |
| D. | winding ratios |
| Answer» C. black, rather than gray, casings | |
| 81. |
A utility pole transformer used to supply a residential customer with two phases uses: |
| A. | two phases on the primary |
| B. | a center tap on the secondary |
| C. | a separate ground for each phase |
| D. | a small coefficient of coupling |
| Answer» C. a separate ground for each phase | |
| 82. |
When a magnet enters a coil and a voltage is induced, the process is known as: |
| A. | an alternation |
| B. | self-inductance |
| C. | counter emf |
| D. | flux linkage |
| Answer» E. | |
| 83. |
Reactance in an inductive circuit will: |
| A. | increase with frequency |
| B. | decrease with frequency |
| C. | be independent from frequency |
| D. | depend on the value of XC |
| Answer» B. decrease with frequency | |
| 84. |
What is remanence? |
| A. | reactance |
| B. | reluctance |
| C. | retentitivity |
| D. | resistance |
| Answer» D. resistance | |
| 85. |
The ___ of a coil is the inherent resistance of the wire. |
| A. | ac resistance |
| B. | reactance |
| C. | winding resistance |
| D. | permeability |
| Answer» D. permeability | |
| 86. |
When the transformer secondary is not loaded: |
| A. | secondary voltage increases |
| B. | no secondary current flows |
| C. | no secondary voltage is present |
| D. | secondary current increases |
| Answer» C. no secondary voltage is present | |
| 87. |
A series RL filter circuit with an output across the inductor will result in what type of filtering? |
| A. | passing of the higher frequencies |
| B. | passing of the lower frequencies |
| C. | blocking of the higher frequencies |
| D. | blocking of a certain range of frequencies |
| Answer» B. passing of the lower frequencies | |
| 88. |
When a transformer secondary lead has been connected to a middle loop that is not an end connector, it is called a: |
| A. | multiple-tapped secondary |
| B. | center-tapped secondary |
| C. | multiple winding secondary |
| D. | single winding secondary |
| Answer» C. multiple winding secondary | |
| 89. |
What are the properties that determine the inductance of a coil? |
| A. | Length of wire, number of turns, type of core material, length of core |
| B. | Number of turns, type of wire, length of core, and cross-sectional area of core |
| C. | Type of core material, number of turns, cross-sectional area of core, and length of core |
| D. | Type of core material, type of wire, number of turns, and cross-sectional area of core |
| Answer» D. Type of core material, type of wire, number of turns, and cross-sectional area of core | |
| 90. |
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 | |
| 91. |
A step-up transformer will have a turns ratio greater than 1. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 92. |
An air-core inductor has a metal core. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 93. |
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 Vac at the secondary? |
| A. | 75 turns |
| B. | 150 turns |
| C. | 900 turns |
| D. | 1920 turns |
| Answer» C. 900 turns | |
| 94. |
Counter emf or induced voltage is: |
| A. | inversely proportional to the change in current |
| B. | directly proportional to the change in time |
| C. | directly proportional to the inductance in henrys |
| D. | inversely proportional to the inductance in henrys |
| Answer» D. inversely proportional to the inductance in henrys | |
| 95. |
A transformer is used: |
| A. | to couple electric energy from one dc circuit to another |
| B. | to couple electric energy from an ac circuit to a dc circuit |
| C. | to couple electric energy from a dc circuit to an ac circuit |
| D. | to couple electric energy from one ac circuit to another |
| Answer» E. | |
| 96. |
A value of "ten to the eighth power magnetic lines of force" is for the term: |
| A. | field |
| B. | flux |
| C. | coulomb |
| D. | weber |
| Answer» E. | |
| 97. |
The total inductance in the given circuit is 0.6 mH. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 98. |
What is electromagnetism? |
| A. | the magnetic field generated around a conductor when a current passes through it |
| B. | the magnetic field generated in a conductor by an external voltage |
| C. | the voltage caused by a magnetic field in a conductor |
| D. | the current generated by an external magnetic field |
| Answer» B. the magnetic field generated in a conductor by an external voltage | |
| 99. |
What will happen when an inductor's magnetic field collapses? |
| A. | Current will double. |
| B. | Voltage will be induced. |
| C. | A new field will expand. |
| D. | Counter emf will be high. |
| Answer» C. A new field will expand. | |
| 100. |
Which transformer turns ratio is needed to match two 16-ohm parallel devices to an output of 22.2 ohms? |
| A. | 1.38:1 |
| B. | 1.67:1 |
| C. | 0.72:1 |
| D. | 0.60:1 |
| Answer» E. | |