ELECTRICAL ENGINEERING- PAGE 10
ELECTRICAL ENGINEERING MCQs- PAGE 10
1. Reduction in supply voltage by 10% will change the torque of an induction motor by
(a) 38% (b) 19% (c) 9.5% (d) No change
Ans: B
2. The step angle of the stepper motor is 2.5°. If the stepping frequency is 3600 pulses per second, then the shaft speed will be
(a) 144 rps (b) 3600 rps (c) 25 rps (d) 2.5 rps
Ans: C
3. A 3-phase, 50 Hz, 500 V induction motor develops 20 hp at slip of 5%. Mechanical losses are 1 hp, and stator loss is 1 kW. The efficiency will be
(a) 95.3% (b) 90.5% (c) 91.3% (d) 85.3%
Ans: D
4. The electric motor used in toys is
(a) capacitor start motor (b) split phase motor (c) shaded pole motor (d) None of these
Ans: C
5. AC servo-motor is basically a
(a) Capacitor motor (b) Two phase motor (c) Three phase motor (d) Universal motor
Ans: B
6. Crawling in an induction motor is due to
(a) Space harmonics produced by winding currents. (b) Time harmonics in supply. (c) Slip ring rotor. (d) Insufficient starting torque.
Ans: A
7. A shaded pole induction motor does not have the advantage of
(a) Rugged construction (b) Low initial as well as maintenance cost (c) High starting torque (d) Comparatively small starting current
Ans: C
8. In three phase 400 volt, 50 Hz supply, the phase to neutral voltage is
(a) 220 Volt (b) 230 Volt (c) 440 Volt (d) 150 Volt
Ans: B
9. Integration of unit ramp function gives
(a) Unit parabolic function (b) Unit ramp function (c) Unit doublet function (d) None of these
Ans: A
10. In house wiring, Black & Green wires indicate
(a) Earth & Neutral respectively (b) Phase & Neutral respectively (c) Phase & Earth respectively (d) Neutral & Earth respectively
Ans: D
11. A 10 kVA, 400 V/200 V, single-phase transformer with 10% impedance, draws a steady short circuit current of
(a) 50 A (b) 150 A (c) 250 A (d) 350 A
Ans: C
12. Kick fuses are used across relay coils to prevent relay operation during
(a) Heavy external faults (b) Inrush current of transformer when they are energised (c) Line to ground faults (d) Bolted faults
Ans: B
13. The electrical energy consumed by an appliance of power rating P watts connected across its rated V for t hours is
(a) P/V .t kWhr
(b) Pt/ 1000 kWhr
(c) Pt kWhr
(d) Pt /3600 kWhr
Ans: B
14. A strain gauge is a passive transducer and is employed for converting
(a) Pressure into change in resistance (b) Force into displacement
(c) Mechanical displacement into a change of resistance (d) None of the above
Ans: C
15. A megger is basically a/an
(a) Moving iron type instrument (b) Moving coil type instrument (c) Hot wire instrument (d) Electrolytic instrument
Ans: B
16. The dynamic characteristics of capacitive transducer are similar to those of
(a) Low-pass filter (b) High-pass filter (c) Notch filter (d) Band-stop filter
Ans: B
17. The insulation resistance test is performed on power lines with
(a) ohm meter (b) earth tester (c) megger (d) Any of these
Ans: C
18. Piezo meter is used to measure
(a) Very high pressure (b) Very low pressure (c) Displacement (d) None of these
Ans: A
19. An ideal synchronous motor has no starting torque because the
(a) Rotor is made up of salient poles. (b) Relative velocity between the stator and rotor mmfs is zero.
(c) Relative velocity between stator and rotor mmfs is not zero. (d) Rotor winding is highly inductive.
Ans: C
20. At a slip of 4%, maximum possible speed of a 3-phase squirrel cage induction motor is
(a) 2880 rpm (b) 3000 rpm (c) 1500 rpm (d) 1440 rpm
Ans: A
21. If the stator winding of a three-phase induction motor is delta connected, the rotor winding
(a) should be delta connected (b) should be star connected (c) should not be delta connected (d) may be delta or star connected
Ans: D
22. Synchronous motors are to be used in situations where
(a) The load is constant. (b) The load is required to be driven at very high speeds.
(c) The load is to be driven at constant speed. (d) The starting torque requirement of the load is very high.
Ans: C
23. When excitation of synchronous motor is increased upto normal excitation from under excitation, armature current
(a) increases (b) decreases (c) remains constant (d) None of the above
Ans: B
24. In a synchronous motor, damper winding is provided to
(a) stabilize rotor motion (b) suppress rotor oscillations (c) develop necessary starting torque (d) (b) and (c) both
Ans: D
25. Direction of rotation of three phase induction motor can be reversed by
(a) interchanging connections of any two phases (b) disconnecting any one phase (c) (a) and (b) both (d) None of the above
Ans: A
26. Variation in dc excitation of a synchronous motor causes variation in
(a) Speed of motor (b) Power factor (c) Armature current (d) Both armature current and power factor
Ans: D
27. A series RLC circuit resonate at 200 Hz. If the capacitance is increased to four times, the circuit will be in resonance at
(a) 100 Hz (b) 200 Hz (c) 400 Hz (d) 800 Hz
Ans: A
28. In a six pole motor, 4 mechanical degrees is equal to
(a) 4 electrical degrees (b) 2 electrical degrees (c) 8 electrical degrees (d) 12 electrical degrees
Ans: D
29. An open-loop system is better than a closed-loop system in terms of
(a) Accuracy (b) Stability (c) Noise reduction (d) Sensitivity
Ans: B
30. A CRO cannot be used for direct measurement of
(a) Voltage (b) Current (c) Frequency (d) Power
Ans: D
31. The cycle time of a PLC is the time it takes to
(a) read all the input signals. (b) read all the input signals, run the program and update outputs.
(c) read an input signal. (d) check all the input signals against the program.
Ans: B
32. The thermocouple pair that gives the maximum sensitivity around 273 °k is
(a) Platinum – Constantan (b) Nichrome – Constantan (c) Nickel – Constantan (d) Copper – Nickel
Ans: B
33. An inverse transducer converts
(a) electrical energy to any other form of energy (b) electrical energy to light energy
(c) mechanical displacement into electrical signal (d) electrical energy to mechanical form
Ans: A
34. Optical Pyrometer is used to measure
(a) Light Intensity (b) Low Temperature (c) High Temperature (d) Light Intensity & High Temperature
Ans: C
35. Horizontal deflection plates of CRO are placed generally
(a) Horizontal (b) Vertical (c) Diagonal (d) (a) or (b)
Ans: B
36. Programming Languages for PLC is/are
(a) Ladder Diagram (b) Function Block Diagram (c) Structured Text (d) All of the above
Ans: D
37. Lissajous pattern obtained on a CRO screen is a circle. Frequency of two signals are
(a) Equal (b) Unequal (c) Zero (d) Infinity
Ans: A
38. Indicating instruments should be
(a) undamped (b) critically damped (c) over damped (d) under damped
Ans: B
39. A controller essentially is a/an
(a) Amplifier (b) Sensor (c) Comparator (d) Clipper
Ans: C
40. To measure insulation resistance of equipments of voltage rating upto 440 V the megger generator must generate
(a) 220 V (b) 440 V (c) 500 V (d) None of these
Ans: C
(a) 38% (b) 19% (c) 9.5% (d) No change
Ans: B
2. The step angle of the stepper motor is 2.5°. If the stepping frequency is 3600 pulses per second, then the shaft speed will be
(a) 144 rps (b) 3600 rps (c) 25 rps (d) 2.5 rps
Ans: C
3. A 3-phase, 50 Hz, 500 V induction motor develops 20 hp at slip of 5%. Mechanical losses are 1 hp, and stator loss is 1 kW. The efficiency will be
(a) 95.3% (b) 90.5% (c) 91.3% (d) 85.3%
Ans: D
4. The electric motor used in toys is
(a) capacitor start motor (b) split phase motor (c) shaded pole motor (d) None of these
Ans: C
5. AC servo-motor is basically a
(a) Capacitor motor (b) Two phase motor (c) Three phase motor (d) Universal motor
Ans: B
6. Crawling in an induction motor is due to
(a) Space harmonics produced by winding currents. (b) Time harmonics in supply. (c) Slip ring rotor. (d) Insufficient starting torque.
Ans: A
7. A shaded pole induction motor does not have the advantage of
(a) Rugged construction (b) Low initial as well as maintenance cost (c) High starting torque (d) Comparatively small starting current
Ans: C
8. In three phase 400 volt, 50 Hz supply, the phase to neutral voltage is
(a) 220 Volt (b) 230 Volt (c) 440 Volt (d) 150 Volt
Ans: B
9. Integration of unit ramp function gives
(a) Unit parabolic function (b) Unit ramp function (c) Unit doublet function (d) None of these
Ans: A
10. In house wiring, Black & Green wires indicate
(a) Earth & Neutral respectively (b) Phase & Neutral respectively (c) Phase & Earth respectively (d) Neutral & Earth respectively
Ans: D
11. A 10 kVA, 400 V/200 V, single-phase transformer with 10% impedance, draws a steady short circuit current of
(a) 50 A (b) 150 A (c) 250 A (d) 350 A
Ans: C
12. Kick fuses are used across relay coils to prevent relay operation during
(a) Heavy external faults (b) Inrush current of transformer when they are energised (c) Line to ground faults (d) Bolted faults
Ans: B
13. The electrical energy consumed by an appliance of power rating P watts connected across its rated V for t hours is
(a) P/V .t kWhr
(b) Pt/ 1000 kWhr
(c) Pt kWhr
(d) Pt /3600 kWhr
Ans: B
14. A strain gauge is a passive transducer and is employed for converting
(a) Pressure into change in resistance (b) Force into displacement
(c) Mechanical displacement into a change of resistance (d) None of the above
Ans: C
15. A megger is basically a/an
(a) Moving iron type instrument (b) Moving coil type instrument (c) Hot wire instrument (d) Electrolytic instrument
Ans: B
16. The dynamic characteristics of capacitive transducer are similar to those of
(a) Low-pass filter (b) High-pass filter (c) Notch filter (d) Band-stop filter
Ans: B
17. The insulation resistance test is performed on power lines with
(a) ohm meter (b) earth tester (c) megger (d) Any of these
Ans: C
18. Piezo meter is used to measure
(a) Very high pressure (b) Very low pressure (c) Displacement (d) None of these
Ans: A
19. An ideal synchronous motor has no starting torque because the
(a) Rotor is made up of salient poles. (b) Relative velocity between the stator and rotor mmfs is zero.
(c) Relative velocity between stator and rotor mmfs is not zero. (d) Rotor winding is highly inductive.
Ans: C
20. At a slip of 4%, maximum possible speed of a 3-phase squirrel cage induction motor is
(a) 2880 rpm (b) 3000 rpm (c) 1500 rpm (d) 1440 rpm
Ans: A
21. If the stator winding of a three-phase induction motor is delta connected, the rotor winding
(a) should be delta connected (b) should be star connected (c) should not be delta connected (d) may be delta or star connected
Ans: D
22. Synchronous motors are to be used in situations where
(a) The load is constant. (b) The load is required to be driven at very high speeds.
(c) The load is to be driven at constant speed. (d) The starting torque requirement of the load is very high.
Ans: C
23. When excitation of synchronous motor is increased upto normal excitation from under excitation, armature current
(a) increases (b) decreases (c) remains constant (d) None of the above
Ans: B
24. In a synchronous motor, damper winding is provided to
(a) stabilize rotor motion (b) suppress rotor oscillations (c) develop necessary starting torque (d) (b) and (c) both
Ans: D
25. Direction of rotation of three phase induction motor can be reversed by
(a) interchanging connections of any two phases (b) disconnecting any one phase (c) (a) and (b) both (d) None of the above
Ans: A
26. Variation in dc excitation of a synchronous motor causes variation in
(a) Speed of motor (b) Power factor (c) Armature current (d) Both armature current and power factor
Ans: D
27. A series RLC circuit resonate at 200 Hz. If the capacitance is increased to four times, the circuit will be in resonance at
(a) 100 Hz (b) 200 Hz (c) 400 Hz (d) 800 Hz
Ans: A
28. In a six pole motor, 4 mechanical degrees is equal to
(a) 4 electrical degrees (b) 2 electrical degrees (c) 8 electrical degrees (d) 12 electrical degrees
Ans: D
29. An open-loop system is better than a closed-loop system in terms of
(a) Accuracy (b) Stability (c) Noise reduction (d) Sensitivity
Ans: B
30. A CRO cannot be used for direct measurement of
(a) Voltage (b) Current (c) Frequency (d) Power
Ans: D
31. The cycle time of a PLC is the time it takes to
(a) read all the input signals. (b) read all the input signals, run the program and update outputs.
(c) read an input signal. (d) check all the input signals against the program.
Ans: B
32. The thermocouple pair that gives the maximum sensitivity around 273 °k is
(a) Platinum – Constantan (b) Nichrome – Constantan (c) Nickel – Constantan (d) Copper – Nickel
Ans: B
33. An inverse transducer converts
(a) electrical energy to any other form of energy (b) electrical energy to light energy
(c) mechanical displacement into electrical signal (d) electrical energy to mechanical form
Ans: A
34. Optical Pyrometer is used to measure
(a) Light Intensity (b) Low Temperature (c) High Temperature (d) Light Intensity & High Temperature
Ans: C
35. Horizontal deflection plates of CRO are placed generally
(a) Horizontal (b) Vertical (c) Diagonal (d) (a) or (b)
Ans: B
36. Programming Languages for PLC is/are
(a) Ladder Diagram (b) Function Block Diagram (c) Structured Text (d) All of the above
Ans: D
37. Lissajous pattern obtained on a CRO screen is a circle. Frequency of two signals are
(a) Equal (b) Unequal (c) Zero (d) Infinity
Ans: A
38. Indicating instruments should be
(a) undamped (b) critically damped (c) over damped (d) under damped
Ans: B
39. A controller essentially is a/an
(a) Amplifier (b) Sensor (c) Comparator (d) Clipper
Ans: C
40. To measure insulation resistance of equipments of voltage rating upto 440 V the megger generator must generate
(a) 220 V (b) 440 V (c) 500 V (d) None of these
Ans: C
41. Which of the following modulation techniques is mostly used in inverters ?
(a) Pulse width modulation (b) Square wave output modulation (c) Both (a) and (b) (d) Neither (a) nor (b)
Ans: A
42. An IGBT has three terminals called
(a) Collector, Emitter and Base (b) Drain, Source and Base (c) Drain, Source and Gate (d) Collector, Emitter and Gate
Ans: D
43. A UPS commonly has following parts : (i) rectifier (ii) inverter (iii) static switch Which of the following is true ?
(a) only (i) (b) only (i) and (ii) (c) (i), (ii) and (iii) (d) only (ii) and (iii)
Ans: C
44. When the SCR conducts, the forward voltage drop will
(a) 0.7 V at all load current (b) 2 to 2.5 V at all load current
(c) increases slightly with load current (d) remains constant with load current
Ans: C
45. A separately excited dc motor is required to be controlled, from a 3-phase supply, for its operation in the first quadrant only. The most preferred converter would be
(a) 3-phase fully controlled converter (b) 3-phase fully controlled converter with free wheel diode
(c) 3-phase dual converter (d) 3-phase half wave converter
Ans: D
46. For an SCR with turn-on time of 5 microsecond, an ideal trigger pulse should have
(a) short rise time with pulse width = 3 µsec (b) long rise time with pulse width = 6 µsec
(c) short rise time with pulse width = 6 µsec (d) None of the above
Ans: C
47. Cyclo converter drives are generally employed in
(a) Traction (b) Milling (c) Generating low frequencies (d) Generating pulses
Ans: A
48. In a dual converter, the circulating current
(a) allows smooth reversal of load current but increases the response time.
(b) allows smooth reversal of load current with improved speed of response.
(c) does not allow smooth reversal of load current but reduces response time.
(d) flows only if there is no interconnecting conductor.
Ans: B
49. A cyclo converter is a
(a) naturally commutated device (b) forced commutated device
(c) can be commutated in both manner (d) None of the above
Ans: A
50. A single phase, half-wave, controlled rectifier has 400 sin (314 t) as the input voltage and R as the load. For a firing angle of 60° for the SCR, the average output voltage is
(a) 240/π (b) 400/π (c) 300/π (d) 200/π
Ans: C
(a) Pulse width modulation (b) Square wave output modulation (c) Both (a) and (b) (d) Neither (a) nor (b)
Ans: A
42. An IGBT has three terminals called
(a) Collector, Emitter and Base (b) Drain, Source and Base (c) Drain, Source and Gate (d) Collector, Emitter and Gate
Ans: D
43. A UPS commonly has following parts : (i) rectifier (ii) inverter (iii) static switch Which of the following is true ?
(a) only (i) (b) only (i) and (ii) (c) (i), (ii) and (iii) (d) only (ii) and (iii)
Ans: C
44. When the SCR conducts, the forward voltage drop will
(a) 0.7 V at all load current (b) 2 to 2.5 V at all load current
(c) increases slightly with load current (d) remains constant with load current
Ans: C
45. A separately excited dc motor is required to be controlled, from a 3-phase supply, for its operation in the first quadrant only. The most preferred converter would be
(a) 3-phase fully controlled converter (b) 3-phase fully controlled converter with free wheel diode
(c) 3-phase dual converter (d) 3-phase half wave converter
Ans: D
46. For an SCR with turn-on time of 5 microsecond, an ideal trigger pulse should have
(a) short rise time with pulse width = 3 µsec (b) long rise time with pulse width = 6 µsec
(c) short rise time with pulse width = 6 µsec (d) None of the above
Ans: C
47. Cyclo converter drives are generally employed in
(a) Traction (b) Milling (c) Generating low frequencies (d) Generating pulses
Ans: A
48. In a dual converter, the circulating current
(a) allows smooth reversal of load current but increases the response time.
(b) allows smooth reversal of load current with improved speed of response.
(c) does not allow smooth reversal of load current but reduces response time.
(d) flows only if there is no interconnecting conductor.
Ans: B
49. A cyclo converter is a
(a) naturally commutated device (b) forced commutated device
(c) can be commutated in both manner (d) None of the above
Ans: A
50. A single phase, half-wave, controlled rectifier has 400 sin (314 t) as the input voltage and R as the load. For a firing angle of 60° for the SCR, the average output voltage is
(a) 240/π (b) 400/π (c) 300/π (d) 200/π
Ans: C
51. Isolators are used for disconnecting a circuit when
(a) Line is energised (b) Line is on full load (c) Line carries no current (d) Can be operated under any condition
Ans: C
52. The transmission line feeding power on either side of the main transmission line is called
(a) Secondary distribution (b) Secondary transmission (c) Primary transmission (d) Primary distribution
Ans: B
53. What is the approximate value of average resistance of a human body ?
(a) 1 kΩ (b) 5 kΩ (c) 10 kΩ (d) 15 kΩ
Ans: A
54. The skin effect of the conductor increases the effective value of
(a) Inductance of the conductor (b) Resistance of the conductor (c) Capacitance of the conductor (d) None of these
Ans: B
55. Which portion of the transmission system is more prone to faults ?
(a) Alternator (b) Transformer (c) Overhead lines (d) Underground cables
Ans: C
56. The insulation strength of EHV lines is mainly governed by
(a) Switching overvoltages (b) Lightning overvoltages (c) Power frequency overvoltages (d) Dynamic overvoltages
Ans: A
57. Pilot relaying schemes are used for the protection of
(a) Bus bars (b) Transformer (c) Instrument transformer (d) Transmission line
Ans: D
58. The restriking voltage is measured in
(a) RMS value (b) Peak value (c) Instantaneous value (d) Average value
Ans: B
60. Which fault gives rise to symmetrical fault currents ?
(a) Single line to ground fault (b) Line to line fault
(c) Double line to ground fault (d) Three phase fault
Ans: D
61. Typical solar cell efficiency is
(a) Less than 5% (b) 12% to 25% (c) 30% to 40% (d) More than 50%
Ans: B
62. India receives solar energy in the range of
(a) 5-7 kWh/m2 for 300-330 days in a year (b) 50-70 kWh/m2 for 300-330 days in a year
(c) 5-7 kWh/m2 for 200-230 days in a year (d) 50-70 kWh/m2 for 200-230 days in a year
Ans: A
63. Biogas comprises mainly of
(a) 60% oxygen and 40% carbon dioxide (b) 60% oxygen and 40% methane
(c) 60% methane and 40% oxygen (d) 60% methane and rest carbon dioxide
Ans: D
64. Global warming is mainly due to
(a) Emission of heat from engines (b) Emission of CO2 due to burning of fossil fuels (c) Use of nuclear energy (d) Air pollution
Ans: B
65. The possible site for Geothermal energy extraction for the purpose of electricity in India is
(a) Madhya Pradesh (b) Kerala (c) Tamil Nadu (d) Assam
Ans: A
66. Horizontal axis and vertical axis are the types of
(a) Nuclear Reactor (b) Wind Mills (c) Bio Gas Reactor (d) Solar Cell
Ans: B
67. The Fill Factor of a silicon solar cell is approximately
(a) 1 (b) 0.7 (c) 0.5 (d) 0
Ans: B
68. Major share of power generated in India is through
(a) Thermal Power Plants (b) Nuclear Power Plants (c) Hydro-electric Power Plants (d) Solar energy
Ans: A
69. Match Lists L-I and L-II below, in respect of India’s installed capacity of nonconventional energy, as on date. L – I L – II 1. Solar Power A. 2800 MW 2. Wind Power B. 3063 MW 3. Bagass Cogeneration C. 1365 MW 4. Biomass Power D. 22,465 MW 1 2 3 4
(a) A B C D (b) B A C D (c) D B A C (d) B D A C
Ans: D
70. When a body reflects all the radiations incident on it, then the body is known as
(a) White body (b) Grey body (c) Black body (d) Transparent body
Ans: A
71. A diesel power station spends 0.25 kg/kWh fuel. If the calorific value is 10,000 kcal/kg then overall efficiency of the power station will be
(a) 25% (b) 30% (c) 34.4% (d) 100%
Ans: C
72. Admittance is the reciprocal of
(a) Impedance (b) Reactance (c) Susceptance (d) Inductance
Ans: A
73. For proper earthing, what should be the maximum value of earth resistance while carrying out the testing of earth continuity path ?
(a) 1 Ω (b) 2 Ω (c) 5 Ω (d) 10 Ω
Ans: A
74. The advantage of using pulverized fuel include
(a) Higher boiler efficiency (b) Easy and complete combustion (c) Low air requirement (d) All of the above
Ans: D
75. Which of the following statements pertains to resistors only ?
(a) They oppose sudden change in voltage. (b) They can act as energy storage device.
(c) They can dissipate desired amount of power. (d) None of the above.
Ans: C
76. What is the maximum number of points of light, fan and socket-outlets that can be connected in one sub-circuit ?
(a) 5 (b) 10 (c) 20 (d) 30
Ans: B
77. Minimum distance of underground cable from the foundation of building should be
(a) 100 cm (b) 50 cm (c) 10 cm (d) 5 cm
Ans: C
78. Official systemetic, scientific study of energy consumption by the related organisation for cost reduction and energy conservation is (a) energy policy (b) energy audit (c) (a) and (b) both (d) None of the above
Ans: B
79. The type of wiring that is highly suitable for a temporary shed is
(a) Cleat wiring (b) Wooden capping and casing wiring (c) Lead sheathed wiring (d) Conduit wiring
Ans: A
80. Which of the following test is carried out to ensure the sufficient strength of insulation between two or more conductors to avoid leakage between them ?
(a) Testing of insulation resistance between wiring and earth
(b) Testing of insulation resistance between conductors
(c) Testing of polarity of single phase switch
(d) Testing of earth continuity path
Ans: B
81. Which distribution system is more reliable ?
(a) Ring main system (b) Tree system (c) Radial system (d) All are equally reliable.
Ans: A
82. HV transmission lines use
(a) Pin type insulators (b) Suspension insulators (c) Both (a) and (b) (d) None of the above
Ans: C
83. 1 Ton (unit of air conditioning load) in terms of kW is
(a) 3.5 kW (b) 4.7 kW (c) 12 kW (d) 10.5 kW
Ans: A
84. A network has 10 nodes and 17 branches. The number of independent mesh equations required to solve the network is
(a) 7 (b) 8 (c) 10 (d) 45
Ans: B
85. Which of the following elements is not bilateral ?
(a) Resistor (b) Inductor (c) Capacitor (d) Transistor
Ans: D
86. Each branch of Y-connected load has resistance of 10 Ω. The resistance of each branch of an equivalent ∆-connected load will be
(a) 30 Ω (b) 100 Ω (c) 110 Ω (d) None of these
Ans: A
87. In applying superposition theorem, to determine branch currents and voltages
(a) all current and voltage sources are shorted. (b) only current sources are open circuited.
(c) only voltage sources are shorted. (d) voltage sources are shorted and current sources are open circuited.
Ans: D
88. The colour having shortest wavelength in the following is
(a) Yellow (b) Blue (c) Orange (d) Green
Ans: B
89. The material used for fuse wire should be of
(a) low resistivity and high melting point (b) high resistivity and high melting point
(c) high resistivity and low melting point (d) low resistivity and low melting point
Ans: D
90. It is desired to illuminate a drawing hall with an average illumination of about 250 lux. The area of hall is 30 m × 20 m. The lamps are to be fitted at 5 m height. Find the number and size of incandescent lamps required for an efficiency of 12 lumen/watt. Utilization factor = 0.4 and maintenance factor = 0.85.
(a) 40 and 1000 W (b) 20 and 500 W (c) 60 and 1000 W (d) None of the above
Ans: A
91. Battery operated scooter for braking uses
(a) plugging (b) mechanical braking (c) regenerative braking (d) rheostatic braking
Ans: B
92. In spot welding, electric supply used is
(a) low voltage high current (b) high voltage low current (c) low voltage low current (d) high voltage high current
Ans: A
93. In the process of refining of metals, the impure metal is made as
(a) Cathode (b) Anode (c) Electrolyte (d) None of the above
Ans: B
94. Minimum clearance above ground of the lowest conductor of an overhead line erected along a street for low and medium voltages as per “Indian Electricity Rules” is
(a) 4.5 metres (b) 6.1 metres (c) 6.5 metres (d) 5.5 metres
Ans: D
95. Synchronous capacitor is
(a) An ordinary static capacitor bank. (b) An over excited synchronous motor driving mechanical load.
(c) An over excited motor running without mechanical load. (d) None of the above
Ans: C
96. In terms of cost, overhead transmission line is better than underground transmission line in the field of
(a) Insulation (b) Right of way (c) Visibility (d) None of these
Ans: A
97. Materials used in plate earthing are
(a) Wood coal (b) Salt, earthing plate (c) (a) and (b) both (d) None of the above
Ans: C
98. The rating of fuse wire is always expressed in
(a) volts (b) amperes (c) ampere-volt (d) ampere-hours
Ans: B
99. An automatic power factor controller cannot achieve
(a) Voltage control (b) kVAR control (c) kW control (d) pf control
Ans: C
100. A single phase energy meter has a constant of 1200 revolution/kWh. When a load of 200 W is connected, the disc rotates at 4.2 revolutions per min. If the load is on for 10 hours, the meter records an excess of
(a) 0.1 kWh (b) 0.2 kWh (c) 1.0 kWh (d) 2.0 kWh
Ans: A
(a) Line is energised (b) Line is on full load (c) Line carries no current (d) Can be operated under any condition
Ans: C
52. The transmission line feeding power on either side of the main transmission line is called
(a) Secondary distribution (b) Secondary transmission (c) Primary transmission (d) Primary distribution
Ans: B
53. What is the approximate value of average resistance of a human body ?
(a) 1 kΩ (b) 5 kΩ (c) 10 kΩ (d) 15 kΩ
Ans: A
54. The skin effect of the conductor increases the effective value of
(a) Inductance of the conductor (b) Resistance of the conductor (c) Capacitance of the conductor (d) None of these
Ans: B
55. Which portion of the transmission system is more prone to faults ?
(a) Alternator (b) Transformer (c) Overhead lines (d) Underground cables
Ans: C
56. The insulation strength of EHV lines is mainly governed by
(a) Switching overvoltages (b) Lightning overvoltages (c) Power frequency overvoltages (d) Dynamic overvoltages
Ans: A
57. Pilot relaying schemes are used for the protection of
(a) Bus bars (b) Transformer (c) Instrument transformer (d) Transmission line
Ans: D
58. The restriking voltage is measured in
(a) RMS value (b) Peak value (c) Instantaneous value (d) Average value
Ans: B
60. Which fault gives rise to symmetrical fault currents ?
(a) Single line to ground fault (b) Line to line fault
(c) Double line to ground fault (d) Three phase fault
Ans: D
61. Typical solar cell efficiency is
(a) Less than 5% (b) 12% to 25% (c) 30% to 40% (d) More than 50%
Ans: B
62. India receives solar energy in the range of
(a) 5-7 kWh/m2 for 300-330 days in a year (b) 50-70 kWh/m2 for 300-330 days in a year
(c) 5-7 kWh/m2 for 200-230 days in a year (d) 50-70 kWh/m2 for 200-230 days in a year
Ans: A
63. Biogas comprises mainly of
(a) 60% oxygen and 40% carbon dioxide (b) 60% oxygen and 40% methane
(c) 60% methane and 40% oxygen (d) 60% methane and rest carbon dioxide
Ans: D
64. Global warming is mainly due to
(a) Emission of heat from engines (b) Emission of CO2 due to burning of fossil fuels (c) Use of nuclear energy (d) Air pollution
Ans: B
65. The possible site for Geothermal energy extraction for the purpose of electricity in India is
(a) Madhya Pradesh (b) Kerala (c) Tamil Nadu (d) Assam
Ans: A
66. Horizontal axis and vertical axis are the types of
(a) Nuclear Reactor (b) Wind Mills (c) Bio Gas Reactor (d) Solar Cell
Ans: B
67. The Fill Factor of a silicon solar cell is approximately
(a) 1 (b) 0.7 (c) 0.5 (d) 0
Ans: B
68. Major share of power generated in India is through
(a) Thermal Power Plants (b) Nuclear Power Plants (c) Hydro-electric Power Plants (d) Solar energy
Ans: A
69. Match Lists L-I and L-II below, in respect of India’s installed capacity of nonconventional energy, as on date. L – I L – II 1. Solar Power A. 2800 MW 2. Wind Power B. 3063 MW 3. Bagass Cogeneration C. 1365 MW 4. Biomass Power D. 22,465 MW 1 2 3 4
(a) A B C D (b) B A C D (c) D B A C (d) B D A C
Ans: D
70. When a body reflects all the radiations incident on it, then the body is known as
(a) White body (b) Grey body (c) Black body (d) Transparent body
Ans: A
71. A diesel power station spends 0.25 kg/kWh fuel. If the calorific value is 10,000 kcal/kg then overall efficiency of the power station will be
(a) 25% (b) 30% (c) 34.4% (d) 100%
Ans: C
72. Admittance is the reciprocal of
(a) Impedance (b) Reactance (c) Susceptance (d) Inductance
Ans: A
73. For proper earthing, what should be the maximum value of earth resistance while carrying out the testing of earth continuity path ?
(a) 1 Ω (b) 2 Ω (c) 5 Ω (d) 10 Ω
Ans: A
74. The advantage of using pulverized fuel include
(a) Higher boiler efficiency (b) Easy and complete combustion (c) Low air requirement (d) All of the above
Ans: D
75. Which of the following statements pertains to resistors only ?
(a) They oppose sudden change in voltage. (b) They can act as energy storage device.
(c) They can dissipate desired amount of power. (d) None of the above.
Ans: C
76. What is the maximum number of points of light, fan and socket-outlets that can be connected in one sub-circuit ?
(a) 5 (b) 10 (c) 20 (d) 30
Ans: B
77. Minimum distance of underground cable from the foundation of building should be
(a) 100 cm (b) 50 cm (c) 10 cm (d) 5 cm
Ans: C
78. Official systemetic, scientific study of energy consumption by the related organisation for cost reduction and energy conservation is (a) energy policy (b) energy audit (c) (a) and (b) both (d) None of the above
Ans: B
79. The type of wiring that is highly suitable for a temporary shed is
(a) Cleat wiring (b) Wooden capping and casing wiring (c) Lead sheathed wiring (d) Conduit wiring
Ans: A
80. Which of the following test is carried out to ensure the sufficient strength of insulation between two or more conductors to avoid leakage between them ?
(a) Testing of insulation resistance between wiring and earth
(b) Testing of insulation resistance between conductors
(c) Testing of polarity of single phase switch
(d) Testing of earth continuity path
Ans: B
81. Which distribution system is more reliable ?
(a) Ring main system (b) Tree system (c) Radial system (d) All are equally reliable.
Ans: A
82. HV transmission lines use
(a) Pin type insulators (b) Suspension insulators (c) Both (a) and (b) (d) None of the above
Ans: C
83. 1 Ton (unit of air conditioning load) in terms of kW is
(a) 3.5 kW (b) 4.7 kW (c) 12 kW (d) 10.5 kW
Ans: A
84. A network has 10 nodes and 17 branches. The number of independent mesh equations required to solve the network is
(a) 7 (b) 8 (c) 10 (d) 45
Ans: B
85. Which of the following elements is not bilateral ?
(a) Resistor (b) Inductor (c) Capacitor (d) Transistor
Ans: D
86. Each branch of Y-connected load has resistance of 10 Ω. The resistance of each branch of an equivalent ∆-connected load will be
(a) 30 Ω (b) 100 Ω (c) 110 Ω (d) None of these
Ans: A
87. In applying superposition theorem, to determine branch currents and voltages
(a) all current and voltage sources are shorted. (b) only current sources are open circuited.
(c) only voltage sources are shorted. (d) voltage sources are shorted and current sources are open circuited.
Ans: D
88. The colour having shortest wavelength in the following is
(a) Yellow (b) Blue (c) Orange (d) Green
Ans: B
89. The material used for fuse wire should be of
(a) low resistivity and high melting point (b) high resistivity and high melting point
(c) high resistivity and low melting point (d) low resistivity and low melting point
Ans: D
90. It is desired to illuminate a drawing hall with an average illumination of about 250 lux. The area of hall is 30 m × 20 m. The lamps are to be fitted at 5 m height. Find the number and size of incandescent lamps required for an efficiency of 12 lumen/watt. Utilization factor = 0.4 and maintenance factor = 0.85.
(a) 40 and 1000 W (b) 20 and 500 W (c) 60 and 1000 W (d) None of the above
Ans: A
91. Battery operated scooter for braking uses
(a) plugging (b) mechanical braking (c) regenerative braking (d) rheostatic braking
Ans: B
92. In spot welding, electric supply used is
(a) low voltage high current (b) high voltage low current (c) low voltage low current (d) high voltage high current
Ans: A
93. In the process of refining of metals, the impure metal is made as
(a) Cathode (b) Anode (c) Electrolyte (d) None of the above
Ans: B
94. Minimum clearance above ground of the lowest conductor of an overhead line erected along a street for low and medium voltages as per “Indian Electricity Rules” is
(a) 4.5 metres (b) 6.1 metres (c) 6.5 metres (d) 5.5 metres
Ans: D
95. Synchronous capacitor is
(a) An ordinary static capacitor bank. (b) An over excited synchronous motor driving mechanical load.
(c) An over excited motor running without mechanical load. (d) None of the above
Ans: C
96. In terms of cost, overhead transmission line is better than underground transmission line in the field of
(a) Insulation (b) Right of way (c) Visibility (d) None of these
Ans: A
97. Materials used in plate earthing are
(a) Wood coal (b) Salt, earthing plate (c) (a) and (b) both (d) None of the above
Ans: C
98. The rating of fuse wire is always expressed in
(a) volts (b) amperes (c) ampere-volt (d) ampere-hours
Ans: B
99. An automatic power factor controller cannot achieve
(a) Voltage control (b) kVAR control (c) kW control (d) pf control
Ans: C
100. A single phase energy meter has a constant of 1200 revolution/kWh. When a load of 200 W is connected, the disc rotates at 4.2 revolutions per min. If the load is on for 10 hours, the meter records an excess of
(a) 0.1 kWh (b) 0.2 kWh (c) 1.0 kWh (d) 2.0 kWh
Ans: A
- UPSC Exam Syllabus- Electrical Engineering
- Electrical Engineering
- Electrical Engineering- Page 1
- Electrical Engineering- Page 2
- Electrical Engineering- Page 3
- Electrical Engineering- Page 4
- Electrical Engineering- Page 5
- Electrical Engineering- Page 6
- Electrical Engineering- Page 7
- Electrical Engineering- Page 8
- Electrical Engineering- Page 9
- Electrical Engineering- Page- 10
- Electrical Engineering- Page- 11