ELECTRICIAN
ELECTRICIAN MCQs
1. Which material has negative temperature coefficient of Resistance ?
(A) Tungsten (B) Eureka (C) Manganin (D) Mica
Ans: D
2. If three resistors of4 Ω are connected in parallel, find the effective resistance.
(A) 12 Ω (B) 4 Ω
(C) 1.33 Ω (D) 1.2 Ω
Ans: C
3. If a 230 V rated heater is connected to 110 V supply, the heat produced by it changes to
(A) 2 times (B) 1/4 times
(C) 1/2 times (D) 4 times
Ans: B
4. Two capacitors of 4 µF and 2 µF are connected parallel to a circuit, then the effective capacitance is
(A) 1.33 µF (B) 8 µF (C) 2 µF (D) 6 µF
Ans: D
5. A capacitor of farad stores a charge of 1 coulomb at 10 volts.
(A) 10 (B) 1 (C) 0.1 (D) 11
Ans: C
6. Example of absolute instrument is
(A) PMMC voltmeter (B) MI Ammeter (C) Wattmeter (D) Tangent Galvanometer
Ans: D
7. The electrostatic effect directly utilized for the operation of
(A) Voltmeter (B) Ammeter (C) Wattmeter (D) Ohmmeter
Ans: A
8. Which material is used for making control springs in electrical measuring instruments ?
(A) Phosphor Bronze (B) Phosphor Brass (C) Tin-Lead Alloy (D) Silicon Steel
Ans: A
9. Working principle ofthermocouple ammeter is based on the
(A) Hall effect
(B) Skin effect
(C) Seebeck effect
(D) Light effect
Ans: C
10. kWh meter is _________instruments.
(A) Indicating
(B) Recording
(C) Deflecting
(D) Integrating
Ans: D
11. A 50 Hz alternating current has the time-period of
(A) 50
(B) 0.02
(C) 0.1
(D) 1
Ans: B
12. Power factor of R-C series circuit is
(A) zero
(B) between zero and one
(C) unity
(D) greater than one
Ans: B
13. Nature of induced current in the dc generator is
(A) Alternating
(B) Direct
(C) Rectified DC
(D) Unidirectional
Ans: A
14. Steinmetz formula is related with
(A) Hysteresis loss (B) Eddy current loss
(C) Friction loss (D) Field copper loss
Ans: A
15. The critical resistance ofa DC generator is the resistance of
(A) Commutator (B) Armature (C) Field (D) Brush
Ans: C
16. The wave winding is suitable for voltage, current dc generators.
(A) high, low (B) high, high
(C) low, high (D) low, low
Ans: A
17. In dc machines the armature winding must be a
(A) lap winding (B) wave winding
(C) closed one (D) simplex winding
Ans: C
18. Which type of DC generators do not need equalizers for satisfactory parallel operation ?
(A) Under compound (B) Series
(C) Over compound (D) Level compound
Ans: A
19. The direction of rotation of a dc motor is found by
(A) Fleming’s right hand rule (B) Faraday’s laws
(C) Fleming’s left hand rule (D) Lens law
Ans: C
20. No load voltage of a dc generator is 240 V and rated load voltage is 220 V. Find the voltage regulation of the generator.
(A) 8.3% (B) 91% (C) 9.1% (D) 83%
Ans: C
21. Which of the following Generator has poorest voltage regulation ?
(A) Shunt (B) Series
(C) Compound (D) Flat compound
Ans: B
22. The external characteristics of a shunt generator is obtained from its characteristics.
(A) Internal (B) Performance (C) Open circuit (D) Load
Ans: C
23. Condition for maximum mechanical power developed in a dc motor is
(A) Eb=V (B) Eb>V
(C) Eb<V (D) Eb= V/2
Ans: D
24. At constant load, the speed ofa dc motor is affected by
(A) Back emf (B) Armature current (C) Field flux (D) Armature resistance
Ans: C
25. In staircase wiring the lamp is operated with
(A) two intermediate switch
(B) two one-way switches
(C) one one—way and one two-way switch
(D) two two-way switches
Ans: D
26. For dc shunt motors, which method is used for wide and very sensitive speed control ?
(A) Armature voltage control (B) Flux control method (C) Tapped field control (D) Ward-Leonard method
Ans: D
27. Which of the following test requires two identical dc shunt machines ?
(A) Retardation test (B) Swinburn’s test (C) Hopkinson’s test (D) No load test
Ans: C
28. Among the following, which is the transmission voltage used in India ?
(A) 1000 V (B) 40000 V (C) 220000 V (D) 440 V
Ans: C
29. The maximum temperature permitted for class ‘F’ insulation is
(A) 155 °C (B) 105 °C
(C) 120 °C (D) 180 °C
Ans: A
30. Which material is used for making resistors of loading rheostats ?
(A) Tungsten (B) Manganin (C) Constantan (D) Brass
Ans: C
31. Earthing is necessary to give protection against
(A) Overloading (B) Electric shock
(C) Short circuit (D) Electric fire
Ans: B
32. The main purpose of core in a transformer is to
(A) Carry primary current
(B) Prevent eddy current
(C) Eliminate hysteresis loss
(D) Decrease reluctance of Magnetic circuit
Ans: D
33. Which material is used for thermal insulation in electrical heating equipments ?
(A) Mica (B) Asbestos
(C) Bakelite (D) Enamel
Ans: B
34. Fusing factor ofa fuse is
(A) More than one (B) Less than one (C) Equal to one (D) Zero
Ans: A
35. The value of forbidden energy gap of silicon atom is
(A) 1.43 eV (B) 0.72 eV
(C) 0.5 eV (D) 1.12 eV
Ans: D
36. Which type of electric lamp is used in Cinema projectors ?
(A) Incandescent lamp (B) Carbon arc lamp (C) Neon lamp (D) Discharge lamp
Ans: B
37. Open circuit test on a transformer is carried out to measure its
(A) Total loss (B) Cu loss (C) Efficiency (D) Core loss
Ans: D
38. Stray loss in DC machines is accounted as
(A) Magnetic and electrical loss (B) Copper loss and core loss
(C) Magnetic and Mechanical loss (D) Windage loss and friction loss
Ans: C
39. Materials for donor impurities in intrinsic semi-conductor
(A) Monovalent (B) Trivalent (C) Tetravalent (D) Pentavalent
Ans: D
40. Which type squirrel cage motors have high starting torque, low starting current and normal slip ?
(A) Class A (B) Class C (C) Class B (D) Class F
Ans: B
41. Stroboscopic method is used to find of an induction motor.
(A) torque (B) slip (C) speed (D) efficiency
Ans: B
42. Which of the following motor is suitable for compressors ?
(A) Universal motor (B) Two value capacitor run motor
(C) Capacitor start and run motor (D) Shaded pole motor
Ans: B
43. The ratio of intensity of magnetisation I to the magnetising force H is called
(A) Permeability (B) Magnetic potential (C) Magnetic field strength (D) Susceptibility
Ans: D
44. Which method is used for measuring dielectric loss of a capacitor ?
(A) Schering Bridge (B) Anderson Bridge (C) Hay’s Bridge (D) De Sauty Bridge
Ans: A
45. Brass contains Copper and
(A) Tin (B) Lead (C) Zinc (D) Nickel
Ans: C
46. The earth resistance of any earthing should not be more than
(A) 1 ohm (B) 5 ohm
(C) 10 Q (D) 3 ohm
Ans: B
47. The minimum size of earth conductor used in a domestic installation is
(A) 8 SWG (B) 12 SWG
(C) 16 SWG (D) 14 SWG
Ans: D
48. In an ac circuit 3 Q resistor is connected in series with a 4 Q capacitive reactance. The impedance of the circuit is
(A) 59 (B) 70 (C) 19 (D) 259
Ans: A
49. The speed of synchronous motor is always
(A) Less than synchronous speed (B) Synchronous speed (C) More than synchronous speed (D) Low speed at heavy load
Ans: B
50. The working of a synchronous motor is similar to
(A) DC series motor (B) The power transformer (C) Induction motor (D) The transmission of mechanical power by a shaft
Ans: D
(A) Tungsten (B) Eureka (C) Manganin (D) Mica
Ans: D
2. If three resistors of4 Ω are connected in parallel, find the effective resistance.
(A) 12 Ω (B) 4 Ω
(C) 1.33 Ω (D) 1.2 Ω
Ans: C
3. If a 230 V rated heater is connected to 110 V supply, the heat produced by it changes to
(A) 2 times (B) 1/4 times
(C) 1/2 times (D) 4 times
Ans: B
4. Two capacitors of 4 µF and 2 µF are connected parallel to a circuit, then the effective capacitance is
(A) 1.33 µF (B) 8 µF (C) 2 µF (D) 6 µF
Ans: D
5. A capacitor of farad stores a charge of 1 coulomb at 10 volts.
(A) 10 (B) 1 (C) 0.1 (D) 11
Ans: C
6. Example of absolute instrument is
(A) PMMC voltmeter (B) MI Ammeter (C) Wattmeter (D) Tangent Galvanometer
Ans: D
7. The electrostatic effect directly utilized for the operation of
(A) Voltmeter (B) Ammeter (C) Wattmeter (D) Ohmmeter
Ans: A
8. Which material is used for making control springs in electrical measuring instruments ?
(A) Phosphor Bronze (B) Phosphor Brass (C) Tin-Lead Alloy (D) Silicon Steel
Ans: A
9. Working principle ofthermocouple ammeter is based on the
(A) Hall effect
(B) Skin effect
(C) Seebeck effect
(D) Light effect
Ans: C
10. kWh meter is _________instruments.
(A) Indicating
(B) Recording
(C) Deflecting
(D) Integrating
Ans: D
11. A 50 Hz alternating current has the time-period of
(A) 50
(B) 0.02
(C) 0.1
(D) 1
Ans: B
12. Power factor of R-C series circuit is
(A) zero
(B) between zero and one
(C) unity
(D) greater than one
Ans: B
13. Nature of induced current in the dc generator is
(A) Alternating
(B) Direct
(C) Rectified DC
(D) Unidirectional
Ans: A
14. Steinmetz formula is related with
(A) Hysteresis loss (B) Eddy current loss
(C) Friction loss (D) Field copper loss
Ans: A
15. The critical resistance ofa DC generator is the resistance of
(A) Commutator (B) Armature (C) Field (D) Brush
Ans: C
16. The wave winding is suitable for voltage, current dc generators.
(A) high, low (B) high, high
(C) low, high (D) low, low
Ans: A
17. In dc machines the armature winding must be a
(A) lap winding (B) wave winding
(C) closed one (D) simplex winding
Ans: C
18. Which type of DC generators do not need equalizers for satisfactory parallel operation ?
(A) Under compound (B) Series
(C) Over compound (D) Level compound
Ans: A
19. The direction of rotation of a dc motor is found by
(A) Fleming’s right hand rule (B) Faraday’s laws
(C) Fleming’s left hand rule (D) Lens law
Ans: C
20. No load voltage of a dc generator is 240 V and rated load voltage is 220 V. Find the voltage regulation of the generator.
(A) 8.3% (B) 91% (C) 9.1% (D) 83%
Ans: C
21. Which of the following Generator has poorest voltage regulation ?
(A) Shunt (B) Series
(C) Compound (D) Flat compound
Ans: B
22. The external characteristics of a shunt generator is obtained from its characteristics.
(A) Internal (B) Performance (C) Open circuit (D) Load
Ans: C
23. Condition for maximum mechanical power developed in a dc motor is
(A) Eb=V (B) Eb>V
(C) Eb<V (D) Eb= V/2
Ans: D
24. At constant load, the speed ofa dc motor is affected by
(A) Back emf (B) Armature current (C) Field flux (D) Armature resistance
Ans: C
25. In staircase wiring the lamp is operated with
(A) two intermediate switch
(B) two one-way switches
(C) one one—way and one two-way switch
(D) two two-way switches
Ans: D
26. For dc shunt motors, which method is used for wide and very sensitive speed control ?
(A) Armature voltage control (B) Flux control method (C) Tapped field control (D) Ward-Leonard method
Ans: D
27. Which of the following test requires two identical dc shunt machines ?
(A) Retardation test (B) Swinburn’s test (C) Hopkinson’s test (D) No load test
Ans: C
28. Among the following, which is the transmission voltage used in India ?
(A) 1000 V (B) 40000 V (C) 220000 V (D) 440 V
Ans: C
29. The maximum temperature permitted for class ‘F’ insulation is
(A) 155 °C (B) 105 °C
(C) 120 °C (D) 180 °C
Ans: A
30. Which material is used for making resistors of loading rheostats ?
(A) Tungsten (B) Manganin (C) Constantan (D) Brass
Ans: C
31. Earthing is necessary to give protection against
(A) Overloading (B) Electric shock
(C) Short circuit (D) Electric fire
Ans: B
32. The main purpose of core in a transformer is to
(A) Carry primary current
(B) Prevent eddy current
(C) Eliminate hysteresis loss
(D) Decrease reluctance of Magnetic circuit
Ans: D
33. Which material is used for thermal insulation in electrical heating equipments ?
(A) Mica (B) Asbestos
(C) Bakelite (D) Enamel
Ans: B
34. Fusing factor ofa fuse is
(A) More than one (B) Less than one (C) Equal to one (D) Zero
Ans: A
35. The value of forbidden energy gap of silicon atom is
(A) 1.43 eV (B) 0.72 eV
(C) 0.5 eV (D) 1.12 eV
Ans: D
36. Which type of electric lamp is used in Cinema projectors ?
(A) Incandescent lamp (B) Carbon arc lamp (C) Neon lamp (D) Discharge lamp
Ans: B
37. Open circuit test on a transformer is carried out to measure its
(A) Total loss (B) Cu loss (C) Efficiency (D) Core loss
Ans: D
38. Stray loss in DC machines is accounted as
(A) Magnetic and electrical loss (B) Copper loss and core loss
(C) Magnetic and Mechanical loss (D) Windage loss and friction loss
Ans: C
39. Materials for donor impurities in intrinsic semi-conductor
(A) Monovalent (B) Trivalent (C) Tetravalent (D) Pentavalent
Ans: D
40. Which type squirrel cage motors have high starting torque, low starting current and normal slip ?
(A) Class A (B) Class C (C) Class B (D) Class F
Ans: B
41. Stroboscopic method is used to find of an induction motor.
(A) torque (B) slip (C) speed (D) efficiency
Ans: B
42. Which of the following motor is suitable for compressors ?
(A) Universal motor (B) Two value capacitor run motor
(C) Capacitor start and run motor (D) Shaded pole motor
Ans: B
43. The ratio of intensity of magnetisation I to the magnetising force H is called
(A) Permeability (B) Magnetic potential (C) Magnetic field strength (D) Susceptibility
Ans: D
44. Which method is used for measuring dielectric loss of a capacitor ?
(A) Schering Bridge (B) Anderson Bridge (C) Hay’s Bridge (D) De Sauty Bridge
Ans: A
45. Brass contains Copper and
(A) Tin (B) Lead (C) Zinc (D) Nickel
Ans: C
46. The earth resistance of any earthing should not be more than
(A) 1 ohm (B) 5 ohm
(C) 10 Q (D) 3 ohm
Ans: B
47. The minimum size of earth conductor used in a domestic installation is
(A) 8 SWG (B) 12 SWG
(C) 16 SWG (D) 14 SWG
Ans: D
48. In an ac circuit 3 Q resistor is connected in series with a 4 Q capacitive reactance. The impedance of the circuit is
(A) 59 (B) 70 (C) 19 (D) 259
Ans: A
49. The speed of synchronous motor is always
(A) Less than synchronous speed (B) Synchronous speed (C) More than synchronous speed (D) Low speed at heavy load
Ans: B
50. The working of a synchronous motor is similar to
(A) DC series motor (B) The power transformer (C) Induction motor (D) The transmission of mechanical power by a shaft
Ans: D
51. Synchronous motor runs with
(A) lagging pf only (B) leading pf only (C) both lagging and leading pf (D) Unity power factor only
Ans: C
52. The binary number 11011 is equal to the decimal
(A) 27 (B) 25
(C) 29 (D) 11
Ans: A
53. Zero power factor method is used to find of an alternators.
(A) Power factor (B) Synchronous impedance (C) Efficiency (D) Voltage regulation
Ans: D
54. A 10 Q resistor, 0.1 H inductor and 150 11F capacitor are connected in series and give a 200 V, 50 Hz ac supply. Find the power factor of the circuit.
(A) 0.6 (B) 0.5 (C) 0.7 (D) 0.9
Ans: C
55. At the time of 3 phase power measurement using two wattmeter method; wattmeter 1 reads positive and wattmeter 2 reads zero, then the power factor is (A) 0.5 (B) 0.8 (C) Unity (D) Zero
Ans: A
56. If a 400 V, 5 HP motor having a cold resistance of armature is 0.25 9 and full load current of 50 A is connected directly to the 400 V supply. The motor draws a starting current of
(A) 50A (B) 1600A (C) 1760A (D) 500A
Ans: B
57. Face-plate type controller is used for starting a
(A) DC series motor (B) DC shunt motor (C) Compound motor (D) Linear induction motor
Ans: A
58. If the value of a resistor is 4.7 i 5% Q, then its colour code is
(A) Gray Violet Gold Silver (B) Gray Blue Silver Gold (C) Yellow Violet Gold Gold (D) Yellow Violet Silver Gold
Ans: C
59. In colour coding of resistors, which band indicates the tolerance value ?
(A) First (B) Fourth (C) Third (D) Fifth
Ans: B
60. Which one of the following motor does not change its direction of rotation ?
(A) Split phase motor (B) Universal motor (C) Stepper motor (D) Shaded pole motor
Ans: D
61. Which diode is used in measuring instruments for protection from overload ?
(A) PN junction diode (B) Zener diode
(C) 1 N 4007 (D) LDR
Ans: B
62. Ripple frequency of a centre tap fullwave rectifier is at 230 V, 50 Hz supply is
(A) 100 Hz (B) 50 Hz (C) 0 Hz (D) 25 Hz
Ans: A
(A) lagging pf only (B) leading pf only (C) both lagging and leading pf (D) Unity power factor only
Ans: C
52. The binary number 11011 is equal to the decimal
(A) 27 (B) 25
(C) 29 (D) 11
Ans: A
53. Zero power factor method is used to find of an alternators.
(A) Power factor (B) Synchronous impedance (C) Efficiency (D) Voltage regulation
Ans: D
54. A 10 Q resistor, 0.1 H inductor and 150 11F capacitor are connected in series and give a 200 V, 50 Hz ac supply. Find the power factor of the circuit.
(A) 0.6 (B) 0.5 (C) 0.7 (D) 0.9
Ans: C
55. At the time of 3 phase power measurement using two wattmeter method; wattmeter 1 reads positive and wattmeter 2 reads zero, then the power factor is (A) 0.5 (B) 0.8 (C) Unity (D) Zero
Ans: A
56. If a 400 V, 5 HP motor having a cold resistance of armature is 0.25 9 and full load current of 50 A is connected directly to the 400 V supply. The motor draws a starting current of
(A) 50A (B) 1600A (C) 1760A (D) 500A
Ans: B
57. Face-plate type controller is used for starting a
(A) DC series motor (B) DC shunt motor (C) Compound motor (D) Linear induction motor
Ans: A
58. If the value of a resistor is 4.7 i 5% Q, then its colour code is
(A) Gray Violet Gold Silver (B) Gray Blue Silver Gold (C) Yellow Violet Gold Gold (D) Yellow Violet Silver Gold
Ans: C
59. In colour coding of resistors, which band indicates the tolerance value ?
(A) First (B) Fourth (C) Third (D) Fifth
Ans: B
60. Which one of the following motor does not change its direction of rotation ?
(A) Split phase motor (B) Universal motor (C) Stepper motor (D) Shaded pole motor
Ans: D
61. Which diode is used in measuring instruments for protection from overload ?
(A) PN junction diode (B) Zener diode
(C) 1 N 4007 (D) LDR
Ans: B
62. Ripple frequency of a centre tap fullwave rectifier is at 230 V, 50 Hz supply is
(A) 100 Hz (B) 50 Hz (C) 0 Hz (D) 25 Hz
Ans: A
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