MCQ Questions for SSC JE Electrical

41. A series resonant circuit implies

(a) zero power factor and maximum current
(b) unity power factor and maximum current
(c) unity power factor and minimum current
(d) zero power factor and minimum current

42. A current i = (10 + 10 sin t) amperes is passed through moving iron type ammeter. Its reading will be

(a) zero
(b) 10 A
(c) 150A
(d) 2A

43. A DC ameter has resistance of 0.1 W and current range is 0 – 100 A. If the range is to be extended to 0 – 500 A, then meter requires shunt resistance of

(a) 0.010 W
(b) 0.011 W
(c) 0.025 W
(d) 1.0 W

44. In which type of welding is a pool of molten metal used ?

(a) Electroslag
(b) Submerged arc
(c) MIG
(d) TIG

45. Plan and butt welds may be used on materials upto approximately

(a) 25 mm thick
(b) 40 mm thick
(c) 50 mm thick
(d) 70 mm thick

46. In arc welding, arc is created between the electrode and work by

(a) flow of current
(b) voltage
(c) materail thickness
(d) contact resistance

47. Mho relay is used to protect

(a) long transmission line
(b) medium length line
(c) short length line
(d) all the above

48. For arc heating, the electrodes are made of

(a) Copper
(b) Aluminium
(c) Graphite
(d) ACSR conductor

49. The most common type of three phase in unsymmetrical fault is

(a) single line to ground
(b) line to line
(c) double line to ground
(d) three phase

50. If supply frequency increases, the skin effect is

(a) Decreased
(b) Increased
(c) Remains same
(d) None of these

51. A PN junction is

(a) a rectifier
(b) an amplifier
(c) an insulator
(d) an oscillator

52. Megger is an instrument, it measures

(a) a very low resistance
(b) insulation resistance
(c) q of coil
(d) inductance of coil

53. Arc lamp operates at

(a) low lagging power factor
(b) high leading power factor
(c) unity power factor
(d) zero power factor

54. The value of V in the circuit shown in the given figure is

(a) 1 V
(b) 2 V
(c) 3 V
(d) 4 V

Answer: (c) 3 V

55. Two heaters rated at 1000 W, 250 V each are connected in series across a 250 V, 50 Hz AC mains. The total power drawn from the supply would be

(a) 1000 watt
(b) 500 watt
(c) 250 watt
(d) 2000 watt

Answer: (b) 500 watt

56. Area of hysteresis loop represents

(a) copper loss
(b) eddy current loss
(c) dielectric loss
(d) hysteresis loss

57. Two coupled coils with L₁= L2 = 0.6 H have a coupling coefficient of K = 0.8. The turns of N₁ N₂ is

(a) 4
(b) 2
(c) 1
(d) 0.5

58. The efficiency for maximum power transfer to the load is

(a) 25%
(b) 50%
(c) 75%
(d) 100%

59. In synchronous motor, minimum armature current occurs at

(a) Zero power factor
(b) Leading power factor
(c) Lagging power factor
(d) Unity power factor

60. High speed alternators usually have

(a) Salient pole rotor
(b) Cylindrical rotor
(c) Both salient pole and cylindrical rotor
(d) None of the above

61. The field winding of an alternator requires

(a) DC supply
(b) AC supply
(c) Pulsating DC
(d) Any one of the above

62. The rotor input when rotor copper loss in an induction motor is 600 W and slip is 3% is

(a) 18 kW
(b) 200 kW
(c) 20 kW
(d) 25 kW

63. Inter poles are meant for

(a) increasing the speed of the motor
(b) increasing the main field
(c) strengthening the main field
(d) reducing sparking at the commutator

64. The purpose of the conservator in a transformer is

(a) to cool the winding
(b) to prevent moisture in the transformer
(c) to prevent short circuit of primary and secondary winding
(d) to take up contraction and expansion of oil

65. In case of a power transformer, the no load current in terms of rated current is

(a) 10 to 20%
(b) 2 to 6%
(c) 15 to 30%
(d) 30 to 50%

66. If copper loss of transformer at 7/8 th full load is 4900W, then its full load copper loss would be

(a) 5600 W
(b) 6400 W
(c) 373 W
(d) 429 W