MCQOPTIONS
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MCQOPTIONS
This section includes 252 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Which of the following can be used as a comparator? |
| A. | zener diode |
| B. | diode |
| C. | operational amplifier |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 52. |
For instrumentation system, precision variable voltage-reference system is necessary. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 53. |
For excellent stability, the zener diode is kept in temperature controlled casket. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 54. |
Stability of output voltage is entirely depended on |
| A. | stability of transformer |
| B. | stability of zener diode |
| C. | quality of wires |
| D. | capacitor values |
| Answer» C. quality of wires | |
| 55. |
Which of the following generate output voltage much closer to true value? |
| A. | true generator |
| B. | precision generator |
| C. | output generator |
| D. | accurate generator |
| Answer» C. output generator | |
| 56. |
Why zener diodes are provided in dc supply? |
| A. | for forward conduction |
| B. | for reverse conduction |
| C. | for reference voltage |
| D. | for increasing amplitude |
| Answer» D. for increasing amplitude | |
| 57. |
Which of the following represent a change of output voltage when load current is increased? |
| A. | line regulation |
| B. | load regulation |
| C. | current regulation |
| D. | voltage regulation |
| Answer» C. current regulation | |
| 58. |
Which of the application’s filters used for? |
| A. | reducing ripples |
| B. | increasing ripples |
| C. | increasing phase change |
| D. | increasing amplitude |
| Answer» B. increasing ripples | |
| 59. |
Which of the following can be a source of supply in dc power supplies? |
| A. | battery |
| B. | dry cell |
| C. | full wave rectifier |
| D. | all of the mentioned |
| Answer» E. | |
| 60. |
The negative polarity is used in the monopolar link because it |
| A. | uses less conductor size |
| B. | is safer |
| C. | produces less radio interference |
| D. | has less resistance |
| Answer» D. has less resistance | |
| 61. |
HVDC transmission has                        as compared to HVAC transmission. |
| A. | smaller transformer size |
| B. | smaller conductor size |
| C. | higher corona loss |
| D. | smaller power transfer capabilities |
| Answer» C. higher corona loss | |
| 62. |
Usually                      batteries are used in the UPS systems. |
| A. | nc |
| B. | li-on |
| C. | lead acid |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| 63. |
                     is used in the rotating type UPS system to supply the mains. |
| A. | dc motor |
| B. | self excited dc generator |
| C. | alternator |
| D. | battery bank |
| Answer» D. battery bank | |
| 64. |
                   is used for critical loads where temporary power failure can cause a great deal of inconvenience. |
| A. | smps |
| B. | ups |
| C. | mps |
| D. | rccb |
| Answer» C. mps | |
| 65. |
SMPS is used for |
| A. | obtaining controlled ac power supply |
| B. | obtaining controlled dc power supply |
| C. | storage of dc power |
| D. | switch from one source to another |
| Answer» C. storage of dc power | |
| 66. |
In the transfer characteristics of a MOSFET, the threshold voltage is the measure of the |
| A. | minimum voltage to induce a n-channel/p- channel for conduction |
| B. | minimum voltage till which temperature is constant |
| C. | minimum voltage to turn off the device |
| D. | none of the above mentioned is true |
| Answer» B. minimum voltage till which temperature is constant | |
| 67. |
Choose the incorrect statement. |
| A. | smps is less sensitive to input voltage variations |
| B. | smps is smaller as compared to rectifiers |
| C. | smps has low input ripple |
| D. | smps is a source of radio interference |
| Answer» D. smps is a source of radio interference | |
| 68. |
In the internal structure of a MOSFET, a parasitic BJT exists between the |
| A. | source & gate terminals |
| B. | source & drain terminals |
| C. | drain & gate terminals |
| D. | there is no parasitic bjt in mosfet |
| Answer» C. drain & gate terminals | |
| 69. |
The output characteristics of a MOSFET, is a plot of |
| A. | id as a function of vgs with vds as a parameter |
| B. | id as a function of vds with vgs as a parameter |
| C. | ig as a function of vgs with vds as a parameter |
| D. | ig as a function of vds with vgs as a parameter |
| Answer» C. ig as a function of vgs with vds as a parameter | |
| 70. |
The arrow on the symbol of MOSFET indicates |
| A. | that it is a n-channel mosfet |
| B. | the direction of electrons |
| C. | the direction of conventional current flow |
| D. | that it is a p-channel mosfet |
| Answer» C. the direction of conventional current flow | |
| 71. |
The controlling parameter in MOSFET is |
| A. | vds |
| B. | ig |
| C. | vgs |
| D. | is |
| Answer» C. vgs | |
| 72. |
33/ Ipk |
| A. | 1- iii , 2- i , 3- ii |
| B. | 1- i , 2- ii , 3- iii |
| C. | 1- iii , 2- ii , 3- i |
| D. | 1- iii , 2- ii , 3- i |
| Answer» C. 1- iii , 2- ii , 3- i | |
| 73. |
What is done in switching regulators to minimize its power dissipation during switching? |
| A. | uses external transistor |
| B. | uses 1mh choke |
| C. | uses external transistor and 1mh choke |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 74. |
Due to centre tap Vm=400/2=200) IRMS=198/√2=140mA, IAVG=2*198/ π=126mA. ϒ=[(140/126)2-1]1/2=0.48. So, ϒ=48%. |
| A. | 0.623 |
| B. | 0.678 |
| C. | 0.693 |
| D. | 0.625 |
| Answer» D. 0.625 | |
| 75. |
In a centre tapped full wave rectifier, RL=1KΩ and for diode Rf=10Ω. The primary voltage is 800sinωt with transformer turns ratio=2. The ripple factor will be |
| A. | 54% |
| B. | 48% |
| C. | 26% |
| D. | 81% |
| Answer» C. 26% | |
| 76. |
A full wave rectifier delivers 50W to a load of 200Ω. If the ripple factor is 2%, calculate the AC ripple across the load. |
| A. | 2v |
| B. | 5v |
| C. | 4v |
| D. | 1v |
| Answer» B. 5v | |
| 77. |
If the peak voltage on a centre tapped full wave rectifier circuit is 5V and diode cut in voltage is 0.7. The peak inverse voltage on diode is |
| A. | 4.3v |
| B. | 9.3v |
| C. | 5.7v d) 10.7v |
| Answer» C. 5.7v d) 10.7v | |
| 78. |
If the input frequency of a half wave rectifier is 100Hz, then the ripple frequency will be |
| A. | 150hz |
| B. | 200hz |
| C. | 100hz |
| D. | 300hz |
| Answer» D. 300hz | |
| 79. |
Transformer utilisation factor of a half wave rectifier is |
| A. | 0.234 |
| B. | 0.279 |
| C. | 0.287 |
| D. | 0.453 |
| Answer» D. 0.453 | |
| 80. |
If peak voltage for a half wave rectifier circuit is 5V and diode cut in voltage is 0.7, then peak inverse voltage on diode will be? |
| A. | 5v |
| B. | 4.9v |
| C. | 4.3v |
| D. | 6.7v |
| Answer» D. 6.7v | |
| 81. |
Efficiency of a centre tapped full wave rectifier is |
| A. | 50% |
| B. | 46% |
| C. | 70% |
| D. | 81.2% |
| Answer» E. | |
| 82. |
694. |
| A. | 50% |
| B. | 60% |
| C. | 40.6% |
| D. | 46% |
| Answer» D. 46% | |
| 83. |
In a half wave rectifier, the sine wave input is 50sin50t. If the load resistance is of 1K, then average DC power output will be? |
| A. | 3.99v |
| B. | 2.5v c) 5.97v d) 6.77v |
| Answer» C. | |
| 84. |
What is the output as a function of the input voltage (for positive values) for the given figure. Assume it’s an ideal op-amp with zero forward drop (Di=0) |
| A. | 0 |
| B. | -vi |
| C. | vi |
| D. | 2vi |
| Answer» D. 2vi | |
| 85. |
The diode in a half wave rectifier has a forward resistance RF. The voltage is Vmsinωt and the load resistance is RL. The DC current is given by |
| A. | vm/√2rl |
| B. | vm/(rf+rl)Ï€ |
| C. | 2vm/√π |
| D. | vm/rl |
| Answer» C. 2vm/√π | |
| 86. |
Filter used in switching regulator’s are also as called |
| A. | dc – ac transformers |
| B. | ac – dc transformers |
| C. | dc transformer |
| D. | ac transformer |
| Answer» D. ac transformer | |
| 87. |
Which of the following is considered to be the most important components of the switching regulator? |
| A. | rc or rlc filter |
| B. | rl or rlc filter |
| C. | orc or rl filter |
| D. | rc, rlc or rl filter |
| Answer» C. orc or rl filter | |
| 88. |
Which is the most commonly used low voltage switching regulators? |
| A. | powdered permalloy toroids |
| B. | fermite ei, u and toroid cores |
| C. | silicon steel ei butt stacks |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 89. |
What should be the frequency range of pulse generator? |
| A. | 250 khz |
| B. | 40 khz |
| C. | 120 khz |
| D. | 20 khz |
| Answer» E. | |
| 90. |
Which among the following act as a switch in switching regulator? |
| A. | rectifiers |
| B. | diode |
| C. | transistors |
| D. | relays |
| Answer» D. relays | |
| 91. |
It may be required to store energy for a specified amount of time during power failure especially if the system is designed for a computer power supply. |
| A. | 1 and 3 |
| B. | 1,2,3 and 4 |
| C. | 2,3 and 4 |
| D. | 1,3 and 4 |
| Answer» C. 2,3 and 4 | |
| 92. |
The switching regulators can operate in |
| A. | step up |
| B. | step down |
| C. | polarity inverting |
| D. | all the mentioned |
| Answer» E. | |
| 93. |
A series switching regulators |
| A. | improves the efficiency of regulators |
| B. | improves the flexibility of switching |
| C. | enhance the response of regulators |
| D. | all of the mentioned |
| Answer» B. improves the flexibility of switching | |
| 94. |
Linear series regulators are suited for application with |
| A. | high current |
| B. | medium current |
| C. | low current |
| D. | none of the mentioned |
| Answer» C. low current | |
| 95. |
Fixed voltage regulators and adjustable regulators are often called as |
| A. | series dissipative regulators |
| B. | shunt dissipative regulators |
| C. | stray dissipative regulators |
| D. | all the mentioned |
| Answer» B. shunt dissipative regulators | |
| 96. |
Switching speed of P+ junction depends on |
| A. | mobility of minority carriers in p junction |
| B. | life time of minority carriers in p junction |
| C. | mobility of majority carriers in n junction |
| D. | life time of minority carriers in n junction |
| Answer» E. | |
| 97. |
Which of the following helps in reducing the switching time of a transistor? |
| A. | a resistor connected from base to ground |
| B. | a resistor connected from emitter to ground |
| C. | a capacitor connected from base to ground |
| D. | a capacitor connected from emitter to ground |
| Answer» B. a resistor connected from emitter to ground | |
| 98. |
The time taken for a transistor to turn from saturation to cut off is |
| A. | inversely proportional to charge carriers |
| B. | directly proportional to charge carriers |
| C. | charging time of the capacitor |
| D. | discharging time of the capacitor |
| Answer» C. charging time of the capacitor | |
| 99. |
Which of the following circuits helps in the applications of switching times? |
| A. | c) |
| B. | d) |
| Answer» C. | |
| 100. |
For the BJT, β=∞, VBEon=0.7V VCEsat=0.7V. The switch is initially closed. At t=0, it is opened. At which time the BJT leaves the active region? |
| A. | 20ms |
| B. | 50ms |
| C. | 60ms |
| D. | 70ms |
| Answer» C. 60ms | |