Previous Year Solved Question Papers

Previous Year Solved Question Papers

MCQs on Electrical Engineering - 3

41. Circular breaker indented for rapid auto re-closing with rated operating duty o-m-co in which m represents
(a) Making
(b) Breaking
(c) Dead time
(d) Re closing

42. The heat produced by an electric heating element is according to
(a) Ohm’s law
(b) Stefan’s law
(c) Faraday’s law
(d) Snell’s law

43. Ajax Wyatt furnace make use of a crucible in
(a) Horizontal
(b) At an angle of 120 degree
(c) Vertical
(d) None of the above

44. High frequency capacitance heating method is employed for heating
(a) Plastic
(b) Wood
(c) Dehydration of food
(d) All the above

45. In carbon arc welding, the carbon electrode with respect to work is
(a) Negative
(b) Positive
(c) As positive or negative
(d) None of the above

46. The filament lamp work at a pf of
(a) 0.5
(b) 1
(c) 0.7
(d) 0

47.  Which lamp has the highest luminous efficiency?
(a) Filament
(b) Neon
(c) Mercury vapor
(d) Sodium vapor

48. in illumination space to height ration is
(a) 1 to 2
(b) 1
(c) Less than 1
(d) None of the above

49. The induction motor cannot run at synchronous speed because if so
(a) Rotor emf would be zero
(b) Rotor current would be zero
(c) Rotor torque would be zero
(d) All of the above

50. Semi closed or totally closed slots are used in 30 Induction Motor essentially to
(a) Reduce magnetizing current
(b) Increase efficiency
(c) Improve staring torque
(d) Increase magnetizing current

51. In DC machine the armature windings are placed on the rotor for effective
(a) Generation of voltage
(b) Development of torque
(c) Commutation
(d) Energy conversion

52. The most powerful electromagnet in a normal DC machine operating at full load condition is
(a) Field winding
(b) Armature winding
(c) Inter pole winding
(d) Compensating winding

53. Which of the following is called as stray flux
(a) Armature flux
(b) Field flux
(c) Leakage flux
(d) None of the above

54. When a coil moves through a time varying flux, the induced emf present in the coil is
(a) Dynamically induced
(b) Statically induced
(c) Motional emf
(d) Both dynamically and statically induced

55. A 30 SCIM stator rewound for 6 poles without any alteration in the rotor will run at sapped
(a) < 1000 rpm
(b) < 1500 rpm
(c) <1200 rpm
(d) 0 rpm

56. A 30 star connected IM takes 20A from supply. When connected in delta, the motor will take a current of 
(a) 20v 3A
(b) 20/v’ 3A
(c) 20A
(d) 10A

57. The armature core of a DC machine is laminated to minimize
(a) Hysteresis loss
(b) Eddy current loss
(c) Mechanical loss
(d) Temperature loss

58. Which part of a DC motor has the maximum flux
(a) Pole core
(b) Interpole
(c) Leading pole tip
(d) Trailing pole tip

59. The air blast circuit breaker have best application in system of operating voltage
(a) Below 132 KV
(b) 132 KV to 400 KV
(c) Above 400 KV
(d) None of the above.

60. The cheapest shielding material used in Nuclear plant is
(a) Concrete
(b) Brick
(c) Boron
(d) Cadmium

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