ELECTRICAL ENGINEERING- PAGE 6
ELECTRICAL ENGINEERING MCQs- PAGE 6
1. Unit of Electrical energy is __________.
(A) Ampere Hour (B) Kilowatt Hour (C) Kilowatt (D) Kilovolt Ampere
Ans: B
2. Magnitude of electrical shock on a human body depends upon __________.
(A) Current flow through the body (B) Path of electric current through the body (C) Duration of electric shock (D) All of the above
Ans: D
3. One of the following components is a passive device __________.
(A) Field effect transistor (B) Silicon controlled rectifier (C) Air core inductor (D) Zener diode
Ans: C
4. Armouring is provided in the underground cable to safeguard against __________.
(A) Mechanical injury (B) Moisture entry (C) White ant attack (D) Brusting of failure
Ans: A
5. The main switch is used in single phase supply is to be provided with __________.
(A) Fuse in both line and neutral (B) A link in the line and a fuse in the neutral (C) A fuse in the line and a link in the neutral (D) None of these
Ans: C
6. Which of the following units is the correct one for reactive power ?
(A) Kilovolt Ampere (B) Kilowatt (C) Megawatt (D) Kilovolt Ampere reactive
Ans: D
7. The type of insulator used for holding high transmission overhead conductor on straight running of poles __________.
(A) Post insulator (B) Pin insulator (C) Stay insulator (D) Shackle insulator
Ans: B
8. A water pump lifts less water than earlier, what could be the reason for this fault ?
(A) Impiller damaged (B) Level of water in pump is too high (C) Pump running in reverse direction (D) Motor running fast
Ans: A
9. In an energy meter the holes of the aluminium disc helps to __________.
(A) Prevent creaping error (B) Reduce the resistance (C) Reduce the friction (D) Reduce the weight of disc
Ans: A
10. Earth leakage circuit breaker is used to disconnect the supply from __________.
(A) Short circuit (B) Ground fault (C) Open circuit (D) Overload
Ans: B
11. In a transformer, the chemical contained inside the Breather is __________.
(A) Mineral oil (B) Salt (C) Silica gel (D) Water
Ans: C
12. The device which can be used as switch as well as protective device is __________.
(A) Double pole Iron clad switch (B) Intermediate switch (C) Earth leakage circuit breaker (D) Miniature circuit breaker
Ans: D
13. Size of hammer is specified by __________.
(A) Length of hammer (B) Diameter of the phase (C) Height of the head (D) Weight of the hammer
Ans: D
14. Gravity controlled instrument has to be kept in __________.
(A) Vertical position (B) Horizontal position (C) Inclined position (D) Any position
Ans: A
15. A sodium vapour lamp gives which colour of light ?
(A) Green colour (B) White colour (C) Yellow colour (D) Red colour
Ans: C
16. High pressure mercury vapour lamp has three pin bayonet cap lamp holder. This is done for __________.
(A) To make a three phase connection (B) Prevent wrong connection (C) To earth the lamp (D) None of the above
Ans: B
17. A choke is generally used in series with fluorescent tube circuit to __________.
(A) Improve the power factor (B) Prevent flickering (C) To make high voltage for conduction (D) Suppress radio interference
Ans: C
18. Three phase distribution transformer are usually connected in __________.
(A) Delta/Delta (B) Star/Star (C) Star/Delta (D) Delta/Star
Ans: D
19. Conductivity of aluminium is __________.
(A) Sixty percent to that of copper (B) Forty percent to that of copper (C) Eighty percent to that of copper (D) Fifty percent to that of copper
Ans: A
20. The flux per unit area of material is known as __________.
(A) Current density (B) Flux density (C) Magnetic lines of force (D) Electromotive force
Ans: B
21. Which lamp has more resistance with same applied voltage ?
(A) Forty watts (B) Hundred watts (C) Sixty watts (D) Fifteen watts
Ans: D
22. Tool used for cutting, twisting or holding of wires or cables for terminations __________.
(A) Insulated combination plier (B) Insulated side cutting plier (C) Insulated round nose plier (D) Insulated flat nose plier
Ans: A
23. Alternating current is converted into direct current by __________.
(A) Alternator (B) Motor (C) Rectifier (D) Transformer
Ans: C
24. Buchholz relay is generally used for the protection of __________.
(A) Transmission line (B) Transformer (C) Alternator (D) Generator
Ans: B
25. Which of the following is conventional source of energy ?
(A) Coal (B) Solar (C) Small Hydro (D) Wind
Ans: A
26. Advantage of Hydro electric power station is __________.
(A) Low cost (B) Free from pollution (C) No fuel transportation problem (D) All of the above
Ans: D
27. Which of the following system electric power maybe transmitted ?
(A) Overhead system (B) Underground system (C) Overhead and underground system (D) None of these
Ans: C
28. The fuel used in nuclear generating power plant is __________.
(A) Crude oil (B) Isotopes of Uranium (C) Liquified hydrogen (D) Methane
Ans: B
29. What is the basic three electrical quantities ?
(A) Resistance, Capacitance, Inductance (B) Power, Voltage, Conductance
(C) Voltage, Current, Resistance (D) Current, Reactance, Inductance
Ans: C
(A) Ampere Hour (B) Kilowatt Hour (C) Kilowatt (D) Kilovolt Ampere
Ans: B
2. Magnitude of electrical shock on a human body depends upon __________.
(A) Current flow through the body (B) Path of electric current through the body (C) Duration of electric shock (D) All of the above
Ans: D
3. One of the following components is a passive device __________.
(A) Field effect transistor (B) Silicon controlled rectifier (C) Air core inductor (D) Zener diode
Ans: C
4. Armouring is provided in the underground cable to safeguard against __________.
(A) Mechanical injury (B) Moisture entry (C) White ant attack (D) Brusting of failure
Ans: A
5. The main switch is used in single phase supply is to be provided with __________.
(A) Fuse in both line and neutral (B) A link in the line and a fuse in the neutral (C) A fuse in the line and a link in the neutral (D) None of these
Ans: C
6. Which of the following units is the correct one for reactive power ?
(A) Kilovolt Ampere (B) Kilowatt (C) Megawatt (D) Kilovolt Ampere reactive
Ans: D
7. The type of insulator used for holding high transmission overhead conductor on straight running of poles __________.
(A) Post insulator (B) Pin insulator (C) Stay insulator (D) Shackle insulator
Ans: B
8. A water pump lifts less water than earlier, what could be the reason for this fault ?
(A) Impiller damaged (B) Level of water in pump is too high (C) Pump running in reverse direction (D) Motor running fast
Ans: A
9. In an energy meter the holes of the aluminium disc helps to __________.
(A) Prevent creaping error (B) Reduce the resistance (C) Reduce the friction (D) Reduce the weight of disc
Ans: A
10. Earth leakage circuit breaker is used to disconnect the supply from __________.
(A) Short circuit (B) Ground fault (C) Open circuit (D) Overload
Ans: B
11. In a transformer, the chemical contained inside the Breather is __________.
(A) Mineral oil (B) Salt (C) Silica gel (D) Water
Ans: C
12. The device which can be used as switch as well as protective device is __________.
(A) Double pole Iron clad switch (B) Intermediate switch (C) Earth leakage circuit breaker (D) Miniature circuit breaker
Ans: D
13. Size of hammer is specified by __________.
(A) Length of hammer (B) Diameter of the phase (C) Height of the head (D) Weight of the hammer
Ans: D
14. Gravity controlled instrument has to be kept in __________.
(A) Vertical position (B) Horizontal position (C) Inclined position (D) Any position
Ans: A
15. A sodium vapour lamp gives which colour of light ?
(A) Green colour (B) White colour (C) Yellow colour (D) Red colour
Ans: C
16. High pressure mercury vapour lamp has three pin bayonet cap lamp holder. This is done for __________.
(A) To make a three phase connection (B) Prevent wrong connection (C) To earth the lamp (D) None of the above
Ans: B
17. A choke is generally used in series with fluorescent tube circuit to __________.
(A) Improve the power factor (B) Prevent flickering (C) To make high voltage for conduction (D) Suppress radio interference
Ans: C
18. Three phase distribution transformer are usually connected in __________.
(A) Delta/Delta (B) Star/Star (C) Star/Delta (D) Delta/Star
Ans: D
19. Conductivity of aluminium is __________.
(A) Sixty percent to that of copper (B) Forty percent to that of copper (C) Eighty percent to that of copper (D) Fifty percent to that of copper
Ans: A
20. The flux per unit area of material is known as __________.
(A) Current density (B) Flux density (C) Magnetic lines of force (D) Electromotive force
Ans: B
21. Which lamp has more resistance with same applied voltage ?
(A) Forty watts (B) Hundred watts (C) Sixty watts (D) Fifteen watts
Ans: D
22. Tool used for cutting, twisting or holding of wires or cables for terminations __________.
(A) Insulated combination plier (B) Insulated side cutting plier (C) Insulated round nose plier (D) Insulated flat nose plier
Ans: A
23. Alternating current is converted into direct current by __________.
(A) Alternator (B) Motor (C) Rectifier (D) Transformer
Ans: C
24. Buchholz relay is generally used for the protection of __________.
(A) Transmission line (B) Transformer (C) Alternator (D) Generator
Ans: B
25. Which of the following is conventional source of energy ?
(A) Coal (B) Solar (C) Small Hydro (D) Wind
Ans: A
26. Advantage of Hydro electric power station is __________.
(A) Low cost (B) Free from pollution (C) No fuel transportation problem (D) All of the above
Ans: D
27. Which of the following system electric power maybe transmitted ?
(A) Overhead system (B) Underground system (C) Overhead and underground system (D) None of these
Ans: C
28. The fuel used in nuclear generating power plant is __________.
(A) Crude oil (B) Isotopes of Uranium (C) Liquified hydrogen (D) Methane
Ans: B
29. What is the basic three electrical quantities ?
(A) Resistance, Capacitance, Inductance (B) Power, Voltage, Conductance
(C) Voltage, Current, Resistance (D) Current, Reactance, Inductance
Ans: C
30. Direction of rotation of a dc motor can be reversed by changing the direction of __________.
(A) Armature current only
(B) Field current only
(C) Either Armature current or Field current only
(D) Both Armature current and Field current
Ans: C
31. A long shunt dc compound generator has armature, shunt and series field windings with 0.01 Ω, 100 Ω, 0.02 Ω respectively. Find the armature current when it is supplying a load of 50 A at 200 V.
(A) 48 A (B) 49 A (C) 51 A (D) 52 A
Ans: D
32. Material used for making brushes in a dc machine is __________.
(A) Aluminium (B) Carbon (C) Nickel (D) Chromium
Ans: B
33. In a metering instrument, hair spring used for providing controlling torque is made of __________.
(A) Copper (B) Carbon (C) Aluminium (D) Phosphor Bronze
Ans: D
34. Creeping in an energy meter occurs when __________.
(A) Only Pressure coil is energized
(B) Only Current coil is energized
(C) Both Pressure coil and Current coil are energized
(D) Both Pressure coil and Current coil are not energized
Ans: A
35. Gain ‘A’ of an amplifier circuit without feedback is found to be 50. To make it an oscillator circuit the value of the positive feedback gain required is __________.
(A) 1 (B) 0.2 (C) 0.02 (D) 0.01
Ans: A
36. Schering bridge is used for measuring unknown __________.
(A) Resistance (B) Inductance (C) Capacitance (D) Impedance
Ans: C
37. LVDT is used for measurement of __________.
(A) Velocity (B) Pressure (C) Tension (D) Displacement
Ans: D
38. All joints in earthing conductors shall be properly tinned because, Tin offers __________.
(A) Corrosion protection (B) Solderability
(C) A better contact surface (D) All of these
Ans: D
39. Which one of the following is used to reduce water hammer effect in Hydro Electric Power Plants ?
(A) Surge Tank (B) Butterfly valve
(C) Globe valve (D) Spill way
Ans: A
40. A generating station has a connected load of 50 MW and a maximum demand of 20 MW. No. of units generated is 60 MWhr for the year. What is the Demand factor ?
(A) 0.33 (B) 0.4 (C) 2.5 (D) 3
Ans: B
41. In an ac transmission system the receiving end voltage is found to be more than the sending end voltage. This phenomenon is called __________.
(A) Harmonics (B) Ferranti effect (C) Corona (D) Skin effect
Ans: B
42. Which one of the following law is helpful to determine the most economical size of the electric power transmission line conductor ?
(A) Ohms Law (B) Kirchoff’s Laws (C) Faradays Law (D) Kelvin’s Law
Ans: D
43. Three 100 Ω resistances are connected in delta and are connected to a 400 V, 3 phase, and 50 Hz ac supply. If one of the resistance is burned out what will be the reduction in power consumption ?
(A) 400 W (B) 800 W (C) 1600 W (D) 3200 W
Ans: C
44. What will be the value of the regulation of the single phase transformer with percentage resistance drop 2% and percentage reactance drop 8% at a power factor of unity.
(A) 2 (B) 5 (C) 8 (D) 10
Ans: A
45. A 30 kVA Delta bank is created by using 3 similar single phase transformers. When one of the transformer is removed then what will be the capacity in kVA of the new arrangement ?
(A) 12.7 (B) 17.3 (C) 20 (D) 30
Ans: B
46. A standard incandescent lamp having a lumen intensity of 160 Cd in all directions gives an illuminance of 40 lux at the surface of a table vertically below the lamp. What is the distance of the lamp above the table ?
(A) 1 m (B) 2 m (C) 3 m (D) 4 m
Ans: B
47. Which one of the following is not the name of ACSR Conductor ?
(A) ANT (B) DOG (C) WOLF (D) TIGER
Ans: A
48. Saving of copper in an autotransformer, compared to ordinary transformer is given by __________ times weight of copper in ordinary transformer.
(A) K (B) 1/K (C) 1–K (D) 1/(1–K)
Ans: A
49. Calculate the number of sub circuits required for an electrification circuit which contains 28 lamps of 100 W.
(A) 1 (B) 2 (C) 3 (D) 4
Ans: D
50. Calculate the number of street lights required for 3 km long street which is to be illuminated by 85 W sodium vapour lamp at a span of 30 meter.
(A) 98 (B) 99 (C) 100 (D) 101
Ans: D
(A) Armature current only
(B) Field current only
(C) Either Armature current or Field current only
(D) Both Armature current and Field current
Ans: C
31. A long shunt dc compound generator has armature, shunt and series field windings with 0.01 Ω, 100 Ω, 0.02 Ω respectively. Find the armature current when it is supplying a load of 50 A at 200 V.
(A) 48 A (B) 49 A (C) 51 A (D) 52 A
Ans: D
32. Material used for making brushes in a dc machine is __________.
(A) Aluminium (B) Carbon (C) Nickel (D) Chromium
Ans: B
33. In a metering instrument, hair spring used for providing controlling torque is made of __________.
(A) Copper (B) Carbon (C) Aluminium (D) Phosphor Bronze
Ans: D
34. Creeping in an energy meter occurs when __________.
(A) Only Pressure coil is energized
(B) Only Current coil is energized
(C) Both Pressure coil and Current coil are energized
(D) Both Pressure coil and Current coil are not energized
Ans: A
35. Gain ‘A’ of an amplifier circuit without feedback is found to be 50. To make it an oscillator circuit the value of the positive feedback gain required is __________.
(A) 1 (B) 0.2 (C) 0.02 (D) 0.01
Ans: A
36. Schering bridge is used for measuring unknown __________.
(A) Resistance (B) Inductance (C) Capacitance (D) Impedance
Ans: C
37. LVDT is used for measurement of __________.
(A) Velocity (B) Pressure (C) Tension (D) Displacement
Ans: D
38. All joints in earthing conductors shall be properly tinned because, Tin offers __________.
(A) Corrosion protection (B) Solderability
(C) A better contact surface (D) All of these
Ans: D
39. Which one of the following is used to reduce water hammer effect in Hydro Electric Power Plants ?
(A) Surge Tank (B) Butterfly valve
(C) Globe valve (D) Spill way
Ans: A
40. A generating station has a connected load of 50 MW and a maximum demand of 20 MW. No. of units generated is 60 MWhr for the year. What is the Demand factor ?
(A) 0.33 (B) 0.4 (C) 2.5 (D) 3
Ans: B
41. In an ac transmission system the receiving end voltage is found to be more than the sending end voltage. This phenomenon is called __________.
(A) Harmonics (B) Ferranti effect (C) Corona (D) Skin effect
Ans: B
42. Which one of the following law is helpful to determine the most economical size of the electric power transmission line conductor ?
(A) Ohms Law (B) Kirchoff’s Laws (C) Faradays Law (D) Kelvin’s Law
Ans: D
43. Three 100 Ω resistances are connected in delta and are connected to a 400 V, 3 phase, and 50 Hz ac supply. If one of the resistance is burned out what will be the reduction in power consumption ?
(A) 400 W (B) 800 W (C) 1600 W (D) 3200 W
Ans: C
44. What will be the value of the regulation of the single phase transformer with percentage resistance drop 2% and percentage reactance drop 8% at a power factor of unity.
(A) 2 (B) 5 (C) 8 (D) 10
Ans: A
45. A 30 kVA Delta bank is created by using 3 similar single phase transformers. When one of the transformer is removed then what will be the capacity in kVA of the new arrangement ?
(A) 12.7 (B) 17.3 (C) 20 (D) 30
Ans: B
46. A standard incandescent lamp having a lumen intensity of 160 Cd in all directions gives an illuminance of 40 lux at the surface of a table vertically below the lamp. What is the distance of the lamp above the table ?
(A) 1 m (B) 2 m (C) 3 m (D) 4 m
Ans: B
47. Which one of the following is not the name of ACSR Conductor ?
(A) ANT (B) DOG (C) WOLF (D) TIGER
Ans: A
48. Saving of copper in an autotransformer, compared to ordinary transformer is given by __________ times weight of copper in ordinary transformer.
(A) K (B) 1/K (C) 1–K (D) 1/(1–K)
Ans: A
49. Calculate the number of sub circuits required for an electrification circuit which contains 28 lamps of 100 W.
(A) 1 (B) 2 (C) 3 (D) 4
Ans: D
50. Calculate the number of street lights required for 3 km long street which is to be illuminated by 85 W sodium vapour lamp at a span of 30 meter.
(A) 98 (B) 99 (C) 100 (D) 101
Ans: D
51. As per IE rules 1956 (Rule No. : 80), Vertical clearance above the highest part of the building immediately under high voltage lines up to and including 33,000 volts is __________.
(A) 1.2 m (B) 2 m (C) 2.7 m (D) 3.7 m
Ans: D
52. The IS code specifying Earthing is __________.
(A) IS 3043 - 1957 (B) IS 4043 - 1957 (C) IS 3043 - 1987 (D) IS 4043 - 1987
Ans: C
53. A hardware circuit is implemented to find the one’s compliment of a 4 digit binary number. This circuit consists of __________.
(A) 4 AND Gates (B) 4 OR Gates (C) 4 NAND Gates (D) 4 NOT Gates
Ans: D
54. Simplification of the boolean expression Y=A+AB yields Y=__________.
(A) A (B) B (C) A+B (D) A⋅B
Ans: A
55. Total number of JK flip flops required to construct a BCD decade counter is __________.
(A) 1 (B) 2 (C) 3 (D) 4
Ans: D
56. Gain of an ideal Op-Amp is __________.
(A) 0 (B) 1 (C) 105 (D) Infinity
Ans: D
57. Which one of the following coordinate system is best used in CAD for drawing a horizontal line if only the starting point and length of the line are given ?
(A) Absolute (B) Relative rectangular (C) Relative Polar (D) None of these
Ans: B
58. The component which makes and breaks the contacts in a motor starter is __________.
(A) Circuit breaker (B) Relay (C) Contactor (D) Push Button
Ans: C
59. A slip ring induction motor runs at 1450 rpm at full load, when connected to 50 Hz supply. Determine the number of poles.
(A) 2 (B) 4 (C) 6 (D) 8
Ans: B
60. The best unit used to represent the torque of an induction motor is __________.
(A) Watts (B) Synchronous N-m (C) Synchronous Watts (D) Synchronous Torque
Ans: C
61. Which one of the following method is not suited for starting a squirrel cage induction motor ?
(A) DOL starting (B) Auto transformer starting (C) Star Delta starting (D) Rotor Resistance starting
Ans: D
62. What happens if single phasing occurs when a 3 phase induction motor is running at 1/4th full load ?
(A) Motor stops (B) Motor stalls (C) Motor keeps running as 1 phase motor (D) Motor keeps running as 3 phase motor
Ans: C
63. The rotor of an induction motor runs nearly at 1/7th of synchronous speed. This phenomenon is called __________.
(A) Cogging (B) Crawling (C) Magnetic Locking (D) Magnetic breaking
Ans: B
64. For a double squirrel cage motor outer gauge resistance is __________ that of inner cage resistance.
(A) Less than (B) Greater than (C) Equal to (D) Half
Ans: B
65. A universal motor runs at 2000 rpm and develops a back emf of 200 V, when connected to 220 V DC supply. At what speed will it run if the motor is connected to a 220 V AC supply. Given that the back emf developed under this condition is 160 V approximately.
(A) 1600 rpm (B) 2000 rpm (C) 2500 rpm (D) Zero
Ans: A
66.Which of the following transistor amplifier configuration is best suited for impedance matching ?
(A) CB (B) CC (C) CE (D) CD
Ans: B
67. At Upf, Effect of armature reaction in alternator is __________.
(A) Cross magnetising (B) De magnetising (C) Magnetising (D) No effect
Ans: A
68. The ratio of OC Voltage to SC current keeping the field excitation constant in an alternator is called __________.
(A) Synchronous resistance (B) Synchronous inductance
(C) Synchronous capacitance (D) Synchronous impedance
Ans: D
69. Hunting in an alternator can be prevented by __________.
(A) Injecting harmonics (B) Damper bars
(C) Inter poles (D) None of the above
Ans: B
70. An alternator connected to a 440 V, 50 Hz supply will run at higher speed when number of poles are __________.
(A) 2 (B) 4 (C) 6 (D) 8
Ans: A
71.Input to a Half Wave Rectifier circuit is a 50 Hz sine wave. What will be the frequency of its output waveform ?
(A) 0 Hz (B) 25 Hz (C) 50 Hz (D) 100 Hz
Ans: C
72. When two or more protective devices are used for the protection of the same circuit, the correct operation of the correct device on occurance of a fault is called __________.
(A) Discrimination (B) Expulsion (C) Drop Out (D) Rupture
Ans: A
73. The transient voltage which appears across the circuit breaker contacts, at the instant of arc being extinguished is known as __________.
(A) Recovery voltage (B) Restriking voltage
(C) System voltage (D) Normal voltage
Ans: B
74. Which of the following is an example for a distance relay ?
(A) Impedance relay (B) Elliptical relay
(C) Quadrilateral relay (D) All the above
Ans: D
75. What will be the content of A register if the following program segment is executed in 8051 microcontroller ?
MOV A,#75 H
MOV B,#30 H
MOV B,A
ADD A,B
(A) A5 (B) EA (C) 105 (D) 150
Ans: B
76. MOV A,@R0. This is an instruction in 8051 microcontroller. What type of addressing mode is used in this instruction ?
(A) Relative Addressing (B) Immediate Addressing (C) Register Indirect Addressing (D) Register Addressing
Ans: C
77. Internal RAM in 8051 microcontroller has capacity of __________ Bytes.
(A) 128 (B) 256 (C) 4 K (D) 64 K
Ans: A
78. Which one of the following is a programming language used for PLC ?
(A) Ladder logic (B) Statement List (C) Function Block Diagram (D) All of these
Ans: D
79. Which one of the following is not a renewable source of energy ?
(A) Solar (B) Fossil Fuel (C) Wind (D) Biomass
Ans: B
80. Solar cells are made off __________.
(A) Silicon (B) Copper (C) Cadmium (D) Aluminium
Ans: A
81. The main constituents of biogas are :
(A) Methane and Carbon dioxide (B) Ethane and Carbon dioxide
(C) Carbon dioxide and Nitrogen (D) Hydrogen and sulphur
Ans: A
82. An energy conversion device that can harness the power of hydrogen is __________.
(A) Fuel cell (B) Biogas plant (C) SHEP (D) Wind mill
Ans: A
83. Magnetic materials are heated with the help of __________.
(A) Electric arc (B) Electric current (C) Radiation (D) Hysterisis loss
Ans: D
84. Select a suitable motor for continuous rolling mills.
(A) DC shunt motor (B) 3 phase slip ring induction motor (C) 3 phase squirrel cage induction motor (D) 3 phase synchronous motor
Ans: D
85. The device used to collect the current from over head conductor for electric traction service is __________.
(A) Phantograph (B) Phonograph (C) Phantogram (D) Phonogram
Ans: A
86. The speed-time characteristics of city service in electric traction system has no __________ period.
(A) Coasting (B) Acceleration (C) Free running (D) Breaking
Ans: C
87. A gate current of 25 mA is applied to turn on an SCR. Anode current flowing through this SCR is found to be 100 A. What will be the Anode current through the SCR if the gate current is reduced gradually to 10 mA. The holding current of this SCR is 10 mA.
(A) Zero (B) 50 A (C) 100 A (D) 200 A
Ans: C
88. The power electronics device which converts constant dc voltage to variable dc voltage is called __________.
(A) Inverter (B) UPS (C) Chopper (D) SCR
Ans: C
89. How many number of SCRs are required for constructing a single phase semi converter circuit ?
(A) 1 (B) 2 (C) 3 (D) 6
Ans: B
90. Buck converter is used as a __________ converter.
(A) Step up (B) Step down (C) Isolation (D) None of these
Ans: B
91. Calculate the back pitch of the simplex progressive lap winding with 24 slot and 4 pole dc armature with 24 commutator segments.
(A) 6 (B) 12 (C) 13 (D) 15
Ans: C
92. A transistor in CB configuration draws a base current of 0.1 mA and emitter current is found to be 1 mA. Determine the value of dc alpha (αdc) of this transistor.
(A) 0.1 (B) 0.9 (C) 1.1 (D) 1.11
Ans: B
93. Which of the following material is used as an insulation between commutator segments ?
(A) Carbon (B) Graphite (C) Mica (D) Silicon
Ans: C
94. Quantity or condition that is varied by the controller in a control system is called __________.
(A) Manipulated variable (B) Controlled variable (C) System variable (D) None of these
Ans: A
95. A metal detector is an example for __________ Proximity sensor.
(A) Inductive (B) Capacitive (C) Conductive (D) Photo electric
Ans: A
96. Single phase ac servo motor has __________ number of windings in stator.
(A) 1 (B) 2 (C) 3 (D) 4
Ans: B
97. In Quartz non digital watches which type of motor is used ?
(A) Servo motor (B) Series motor (C) Stepper motor (D) No motor is used
Ans: C
98. In two position control system which type of control action is used ?
(A) P+I (B) P+D (C) I+D (D) Bang-Bang control
Ans: D
99. Small computerized electronics units deployed in the field at specific sites and locations for the implementation of SCADA is called __________.
(A) RTU (B) SCADA Master (C) HMI (D) DATA Logger
Ans: A
100. Primary and secondary windings of a transformer are interleaved for __________.
(A) Easy construction (B) Increasing leakage reactance (C) Reducing Magnetic leakage (D) Reducing cost
Ans: C
(A) 1.2 m (B) 2 m (C) 2.7 m (D) 3.7 m
Ans: D
52. The IS code specifying Earthing is __________.
(A) IS 3043 - 1957 (B) IS 4043 - 1957 (C) IS 3043 - 1987 (D) IS 4043 - 1987
Ans: C
53. A hardware circuit is implemented to find the one’s compliment of a 4 digit binary number. This circuit consists of __________.
(A) 4 AND Gates (B) 4 OR Gates (C) 4 NAND Gates (D) 4 NOT Gates
Ans: D
54. Simplification of the boolean expression Y=A+AB yields Y=__________.
(A) A (B) B (C) A+B (D) A⋅B
Ans: A
55. Total number of JK flip flops required to construct a BCD decade counter is __________.
(A) 1 (B) 2 (C) 3 (D) 4
Ans: D
56. Gain of an ideal Op-Amp is __________.
(A) 0 (B) 1 (C) 105 (D) Infinity
Ans: D
57. Which one of the following coordinate system is best used in CAD for drawing a horizontal line if only the starting point and length of the line are given ?
(A) Absolute (B) Relative rectangular (C) Relative Polar (D) None of these
Ans: B
58. The component which makes and breaks the contacts in a motor starter is __________.
(A) Circuit breaker (B) Relay (C) Contactor (D) Push Button
Ans: C
59. A slip ring induction motor runs at 1450 rpm at full load, when connected to 50 Hz supply. Determine the number of poles.
(A) 2 (B) 4 (C) 6 (D) 8
Ans: B
60. The best unit used to represent the torque of an induction motor is __________.
(A) Watts (B) Synchronous N-m (C) Synchronous Watts (D) Synchronous Torque
Ans: C
61. Which one of the following method is not suited for starting a squirrel cage induction motor ?
(A) DOL starting (B) Auto transformer starting (C) Star Delta starting (D) Rotor Resistance starting
Ans: D
62. What happens if single phasing occurs when a 3 phase induction motor is running at 1/4th full load ?
(A) Motor stops (B) Motor stalls (C) Motor keeps running as 1 phase motor (D) Motor keeps running as 3 phase motor
Ans: C
63. The rotor of an induction motor runs nearly at 1/7th of synchronous speed. This phenomenon is called __________.
(A) Cogging (B) Crawling (C) Magnetic Locking (D) Magnetic breaking
Ans: B
64. For a double squirrel cage motor outer gauge resistance is __________ that of inner cage resistance.
(A) Less than (B) Greater than (C) Equal to (D) Half
Ans: B
65. A universal motor runs at 2000 rpm and develops a back emf of 200 V, when connected to 220 V DC supply. At what speed will it run if the motor is connected to a 220 V AC supply. Given that the back emf developed under this condition is 160 V approximately.
(A) 1600 rpm (B) 2000 rpm (C) 2500 rpm (D) Zero
Ans: A
66.Which of the following transistor amplifier configuration is best suited for impedance matching ?
(A) CB (B) CC (C) CE (D) CD
Ans: B
67. At Upf, Effect of armature reaction in alternator is __________.
(A) Cross magnetising (B) De magnetising (C) Magnetising (D) No effect
Ans: A
68. The ratio of OC Voltage to SC current keeping the field excitation constant in an alternator is called __________.
(A) Synchronous resistance (B) Synchronous inductance
(C) Synchronous capacitance (D) Synchronous impedance
Ans: D
69. Hunting in an alternator can be prevented by __________.
(A) Injecting harmonics (B) Damper bars
(C) Inter poles (D) None of the above
Ans: B
70. An alternator connected to a 440 V, 50 Hz supply will run at higher speed when number of poles are __________.
(A) 2 (B) 4 (C) 6 (D) 8
Ans: A
71.Input to a Half Wave Rectifier circuit is a 50 Hz sine wave. What will be the frequency of its output waveform ?
(A) 0 Hz (B) 25 Hz (C) 50 Hz (D) 100 Hz
Ans: C
72. When two or more protective devices are used for the protection of the same circuit, the correct operation of the correct device on occurance of a fault is called __________.
(A) Discrimination (B) Expulsion (C) Drop Out (D) Rupture
Ans: A
73. The transient voltage which appears across the circuit breaker contacts, at the instant of arc being extinguished is known as __________.
(A) Recovery voltage (B) Restriking voltage
(C) System voltage (D) Normal voltage
Ans: B
74. Which of the following is an example for a distance relay ?
(A) Impedance relay (B) Elliptical relay
(C) Quadrilateral relay (D) All the above
Ans: D
75. What will be the content of A register if the following program segment is executed in 8051 microcontroller ?
MOV A,#75 H
MOV B,#30 H
MOV B,A
ADD A,B
(A) A5 (B) EA (C) 105 (D) 150
Ans: B
76. MOV A,@R0. This is an instruction in 8051 microcontroller. What type of addressing mode is used in this instruction ?
(A) Relative Addressing (B) Immediate Addressing (C) Register Indirect Addressing (D) Register Addressing
Ans: C
77. Internal RAM in 8051 microcontroller has capacity of __________ Bytes.
(A) 128 (B) 256 (C) 4 K (D) 64 K
Ans: A
78. Which one of the following is a programming language used for PLC ?
(A) Ladder logic (B) Statement List (C) Function Block Diagram (D) All of these
Ans: D
79. Which one of the following is not a renewable source of energy ?
(A) Solar (B) Fossil Fuel (C) Wind (D) Biomass
Ans: B
80. Solar cells are made off __________.
(A) Silicon (B) Copper (C) Cadmium (D) Aluminium
Ans: A
81. The main constituents of biogas are :
(A) Methane and Carbon dioxide (B) Ethane and Carbon dioxide
(C) Carbon dioxide and Nitrogen (D) Hydrogen and sulphur
Ans: A
82. An energy conversion device that can harness the power of hydrogen is __________.
(A) Fuel cell (B) Biogas plant (C) SHEP (D) Wind mill
Ans: A
83. Magnetic materials are heated with the help of __________.
(A) Electric arc (B) Electric current (C) Radiation (D) Hysterisis loss
Ans: D
84. Select a suitable motor for continuous rolling mills.
(A) DC shunt motor (B) 3 phase slip ring induction motor (C) 3 phase squirrel cage induction motor (D) 3 phase synchronous motor
Ans: D
85. The device used to collect the current from over head conductor for electric traction service is __________.
(A) Phantograph (B) Phonograph (C) Phantogram (D) Phonogram
Ans: A
86. The speed-time characteristics of city service in electric traction system has no __________ period.
(A) Coasting (B) Acceleration (C) Free running (D) Breaking
Ans: C
87. A gate current of 25 mA is applied to turn on an SCR. Anode current flowing through this SCR is found to be 100 A. What will be the Anode current through the SCR if the gate current is reduced gradually to 10 mA. The holding current of this SCR is 10 mA.
(A) Zero (B) 50 A (C) 100 A (D) 200 A
Ans: C
88. The power electronics device which converts constant dc voltage to variable dc voltage is called __________.
(A) Inverter (B) UPS (C) Chopper (D) SCR
Ans: C
89. How many number of SCRs are required for constructing a single phase semi converter circuit ?
(A) 1 (B) 2 (C) 3 (D) 6
Ans: B
90. Buck converter is used as a __________ converter.
(A) Step up (B) Step down (C) Isolation (D) None of these
Ans: B
91. Calculate the back pitch of the simplex progressive lap winding with 24 slot and 4 pole dc armature with 24 commutator segments.
(A) 6 (B) 12 (C) 13 (D) 15
Ans: C
92. A transistor in CB configuration draws a base current of 0.1 mA and emitter current is found to be 1 mA. Determine the value of dc alpha (αdc) of this transistor.
(A) 0.1 (B) 0.9 (C) 1.1 (D) 1.11
Ans: B
93. Which of the following material is used as an insulation between commutator segments ?
(A) Carbon (B) Graphite (C) Mica (D) Silicon
Ans: C
94. Quantity or condition that is varied by the controller in a control system is called __________.
(A) Manipulated variable (B) Controlled variable (C) System variable (D) None of these
Ans: A
95. A metal detector is an example for __________ Proximity sensor.
(A) Inductive (B) Capacitive (C) Conductive (D) Photo electric
Ans: A
96. Single phase ac servo motor has __________ number of windings in stator.
(A) 1 (B) 2 (C) 3 (D) 4
Ans: B
97. In Quartz non digital watches which type of motor is used ?
(A) Servo motor (B) Series motor (C) Stepper motor (D) No motor is used
Ans: C
98. In two position control system which type of control action is used ?
(A) P+I (B) P+D (C) I+D (D) Bang-Bang control
Ans: D
99. Small computerized electronics units deployed in the field at specific sites and locations for the implementation of SCADA is called __________.
(A) RTU (B) SCADA Master (C) HMI (D) DATA Logger
Ans: A
100. Primary and secondary windings of a transformer are interleaved for __________.
(A) Easy construction (B) Increasing leakage reactance (C) Reducing Magnetic leakage (D) Reducing cost
Ans: C
- UPSC Exam Syllabus- Electrical Engineering
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