MCQ Qestions for SSC JE Electrical

52. If a combination of HRC fuse and circuit breaker is used, the circuit breaker operates

(a) for low overload currents
(b) for short-circuit current
(c) under all abnormal currents
(d) combination is never used in practice

53. A synchronous phase modifier as compared to a synchronous motor used for mechanical load has

(a) Larger shaft and higher speed
(b) Smaller shaft and higher speed
(c) Larger shaft and smaller speed
(d) Smaller shaft and smaller speed

54. A 100V/10V, 50VA transformer is converted to 100V/110V autotransformer, the rating of the auto-transformer will be

(a) 550 VA
(b) 500 VA
(c) 110 VA
(d) 100 VA

Answer: (a) 550 VA

55. Induction generator works between the slip of

(a) 1 < s < 2
(b) 0.1 < s < 1.0
(c) s < 0.0
(d) None of the above

Answer: (c) s < 0.0

56. Mho relay is normally used for the protection of

(a) Long transmission lines
(b) Medium length lines
(c) Short length lines
(d) No length criterion

57. A lightning arrestor is usually located nearer to

(a) busbar
(b) transformer
(c) circuit breaker
(d) isolator

58. For traction work, which motor is preferred?

(a) Synchronous motor
(b) Three phase induction motor
(c) DC series motor
(d) Universal motor

59. Which motor has widest variety of methods for speed control ?

(a) DC shunt motor
(b) Synchronous motor
(c) Slip ring induction motor
(d) Scharge motor

60. Which of the following electric discharge lamps gives highest lumens per watt ?

(a) Sodium vapor lamp
(b) Neon lamp
(c) Mercury vapor lamp at low pressure
(d) Mercury vapor lamp at high pressure

61. The function of choke in the flourescent tube circuit is to

(a) Eliminate radio interference
(b) Reduce noise
(c) Reduce flicker
(d) Initiate the arc and stabilise it

62. Electric power for illumination in locomotive is provided by

(a) Main stream engine
(b) Small turbo generator
(c) Battery
(d) Solar cells