SSC junior Engineer Exam 2015

1. Which of the following motors is used in mixies ?

A) Reluctance motor
B) Rupulsion motor
C) Hysteresis motor
D) Universal motors

... Answer is D)
Watch the Video .

2. When the current through the coil of an electromagnet reverses, the ?

A) direction of the magnetic field reverses
B) magnetic field expands
C) direction of the magnetic field remains unchanged
D) magnetic field collapses

... Answer is A)
Watch the Video .

3. An arc blow is a welding defect that is countered with the help of carrying ?

A) The arc welding using DC
B) The thermit welding.
C) The resistance welding
D) The arc welding using AC supply

... Answer is A)
Watch the Video .

4. What is the maximum number of point of light, fan and socket-outlets that can be connected in one sub-circuit ?

A) Twelve
B) Ten
C) Four
D) Six

... Answer is B)
Watch the Video .

5. Which of the following braking is not suitable for motors ?

A) Plugging
B) Dynamic braking
C) Friction braking
D) Regenerative braking

... Answer is C)
Watch the Video .

6. Locked rotor current of a shaded pole motor is ?

A) less than full load current
B) several times the full load
C) slightly more than full load
D) equal to full load current

... Answer is C)
Watch the Video .

7. In a Three phase system, the volt ampere rating is given by ?

A) root3 VL IL
B) 3 VL IL
C) VL IL
D) Vph Iph

... Answer is A)
Watch the Video .

8. In Bipolar Junction transistors, the type of configuration which will give both voltage gain and current fgain is ?

A) CC
B) CB
C) CE
D) None of the options

... Answer is C)
Watch the Video .

9. If 750 µA is flowing through 11 kΩ of resistance, what is the voltage drop across the resistor ?

A) 82.5 V
B) 146 V
C) 8.25 V
D) 14.6 V

... Answer is C)
Watch the Video .

10. The current 'I' in the electric circuit shown below is ?

A) 1.7A
B) 1A
C) 2.7A
D) 3.7A

... Answer is A)
Watch the Video .

11. How much energy is stored by a 100 mH inductance when a current of 1 A is flowing through it ?

A) 5.0J
B) 0.5J
C) 0.05J
D) 0.005

... Answer is C)
Watch the Video .

12. The no load input power to a transformer is practically equal to____loss in the transformer ?

A) Windage
B) Copper
C) Iron
D) Eddy current

... Answer is C)
Watch the Video .

13. A salient-pole synchronous motor is operating at 1/4 full load. If its field current is suddenly switched off, it would ?

A) run at super-synchronous speed
B) stop running
C) run at sub-synchronous speed
D) synchronous speed

... Answer is D)
Watch the Video .

14. If two capacitances C1 and C2 are connected in parallel then the equivalent capacitance is given by ?

A) C1C2
B) C1*C2 /C1+C2
C) C1/C2
D) C1+C2

... Answer is D)
Watch the Video .

15. If static voltage of a squirrel cage induction motor is reduced to 50 percent of its rated vlue, torque developed is reduced by how many percentage of its full load value ?

A) 25%
B) 50%
C) 57.7%
D) 75%

... Answer is A)
Watch the Video .

16. The Superposition theorem is used when the circuit contains ?

A) A single voltage source
B) active elements only
C) a number of voltage
D) passive elements only

... Answer is C)
Watch the Video .

17. If the number of turns of a coil is increased, its inductance: ?

A) is increased
B) remains the same
C) none of the options
D) is decreased

... Answer is A)
Watch the Video .

18. When a source is delivering maximum power to the load, the efficiency will be ?

A) 50%
B) maximum
C) above 50%
D) below 50%

... Answer is A)
Watch the Video .

19. The primary and secondary windings of a transformer are wound on the top of each other in order to reduce___ ?

A) copper losses
B) iron losses
C) winding resistance
D) leakage reactance

... Answer is D)
Watch the Video .

20. In a pure inductive circuit if rthe supply frequency is reduced to 1 2, the current will ?

A) be four times as high
B) be reduced to one fourth
C) be doubled
D) be reduced by half

... Answer is C)
Watch the Video .

21. Two lamps, Green (G) and Red (R) are connected in a motor circuit as shown in the fig. The conditions under which the lamps will burn are(Supply is available at terminals A & B) ?

A) Green and red lamp burns when switch 'S' is closed
B) Green lamp burns always, red lamp burns only when swith 'S' is closed.
C) Green lamp burns only when 'S' is open and red lamp burns only when 'S' is closed.
D) Green lamp will not burn always, red lamp burns only when switch 'S' is closed.

... Answer is C)
Watch the Video .

22. Modern electronic multimeters measure resistance by ?

A) Using an electronic bridge compensator for nulling
B) Using a bridge circuit
C) Using a electrical bridge circuit
D) Forcing a constant current and measuring the voltage across the unknown resistance

... Answer is D)
Watch the Video .

23. As the load is increased, the speed of a dc shunt motor ?

A) Increases proportionately
B) Reduces slightly
C) Remains constant
D) Increases slightly

... Answer is B)
Watch the Video .

24. In batton wiring the cables are carried on seasoned teak wood perfectly straight and well varnished teak wood batton of thickness not less than ?

A) 1 cm
B) 3 cm
C) 2 cm
D) 4 cm

... Answer is A)
Watch the Video .

25. If the co-efficient of coupling between two coil is increased, mutual inductance between the coils ?

A) is decreased
B) is increased
C) remains unchanged
D) changes depend on current

... Answer is B)
Watch the Video .

26. An amplifier has a gain of 10,000 expressed in decibels the gain is ?

A) 10
B) 40
C) 80
D) 100

... Answer is C)
Watch the Video .

27. In a Parallel RLC circuit if the lower cut-off frequency is 2400 Hz and the upper cut of frequency is 2800 Hz, What is the band width ?

A) 5200 Hz
B) 2400 HZ
C) 2800 Hz
D) 400 Hz

... Answer is D)
Watch the Video .

28. Which of the following fault is coming under symmetrical fault ?

A) LLG fault
B) LG fault
C) LLLG fault
D) LL fault

... Answer is C)
Watch the Video .

29. Which of the following motors is preferred for tape-recorders ?

A) Two valve capacitor motor
B) Universal motor
C) Shaded pole motor
D) Hysteresis motor

... Answer is D)
Watch the Video .

30. A 150 V moving iron voltmeter of accuracy class 1.0 reads 75 V when used in a circuit under standard conditions. The maximum possible percentage error in the reading is ?

A) 4.0
B) 2.0
C) 1.0
D) 0.5

... Answer is B)
Watch the Video .

31. There are 3 lamps 40 W, 100 W. To realise the full rated power of the lamps they are to be connected in ?

A) Series or parallel
B) Series only
C) Parallel only
D) Series-parallel

... Answer is C)
Watch the Video .

32. A current of 2A passes through a coil of 350 kms wound on a ring of mean diameter 12 cm. The flux density established in the ring is 1-4 wb/m2. Find the value of relative permeability of Iron. ?

A) 1200
B) 210×103
C) 600
D) 191

... Answer is C)
Watch the Video .

33. Which instrument is used to measure the high resistance ?

A) Kelvin's Double bridge
B) Carey-Foster bridge
C) Megger
D) Wheat stone bridge

... Answer is C)
Watch the Video .

34. A short shunt compound generator supplies a loud current of 100 A at 250 V. The generator has the following winding resistances: shunt field = 130Ω, Armature = 0.1Ω, and series field = 0.1Ω, Find the Emf generated if the brush drop is IV per brush ?

A) 262. 0 volt
B) 272.2 volt
C) 262.2 volt
D) 272.0 volt

... Answer is B)
Watch the Video .

35. A 200 V lamp takes a current of 1 A, it produces a total flux of 2860 lumens. The efficiency of the lamp is ?

A) 14.3 lumens/W
B) 10.9 lumens/W
C) 8.9 lumens/W
D) 9.9 lumens/W

... Answer is A)
Watch the Video .

36. The per phase D.C. armature resistance of an alternator is 0.5 Ω. The effective a. c. armature resistance would be about ?

A) 0.25Ω
B) 0.5Ω
C) 1Ω
D) 0.75Ω

... Answer is D)
Watch the Video .

37. Find the node voltage VA. ?

A) 5 V
B) 6 V
C) 5.66V
D) 6.66V

... Answer is B)
Watch the Video .

38. An electric heater draws 3.5 A from a 110 V source. The resistance of the heating element is approximately ?

A) 38.5 Ω
B) 31 Ω
C) 385 Ω
D) 3.1 Ω

... Answer is B)
Watch the Video .

39. A node in a circuit is defined as a: ?

A) closed path
B) junction of two or more elements.
C) group of interconnected
D) open terminal of an element.

... Answer is B)
Watch the Video .

40. If the power factor is high, then the consumer maximum KVA demand ?

A) remains constant
B) increases
C) decreases
D) becomes Zero

... Answer is C)
Watch the Video .

41. Mutual inductance between two coils is 4 H. If current in one coil changes at the rate of 2A/sec, then emf induced in the other coil is ?

A) 5.0 V
B) 0.5 V
C) 2 V
D) 8 V

... Answer is D)
Watch the Video .

42. The rate of change of current in a 4 H inductor is 2 Amps/sec. Find the voltage across inductor. ?

A) 0.8V
B) 2V
C) 8V
D) 16V

... Answer is C)
Watch the Video .

43. A 10 pole 25 Hz alternator is directly coupled to and is driven by 60 Hz synchronous motor then the number of poles in a synchronous motor are ?

A) 48 poles
B) 12 poles
C) 24 poles
D) None of the options

... Answer is C)
Watch the Video .

44. To operate properly a transistor's base-emitter junction must be forward biased with reverse bias applied to which junction ?

A) Collector-emitter
B) Base-emitter
C) Collector-base
D) Base-collector

... Answer is C)
Watch the Video .

45. The no load primary current I0 is about _____ of full load primary current of a transformer ?

A) 30-40%
B) 3-5%
C) 15-30%
D) above 40%

... Answer is B)
Watch the Video .

46. An active element in a circuit is one which ?

A) both receives and supplies energy
B) dissipates energy
C) supplies energy
D) receives energy

... Answer is C)
Watch the Video .

47. The purpose of starting winding in a singlephase induction motor is to ?

A) Limit temperature rise of the machine
B) Reduce losses
C) Produce rotating flux in conjunction with main winding.
D) Increase losses.

... Answer is C)
Watch the Video .

48. Leakage flux in a transformer occurs because ?

A) applied voltage is sinusoidal
B) iron core has high permeability
C) transformer is not an efficient device
D) air is not a good magnetic insulator

... Answer is D)
Watch the Video .

49. A Primary cell has an emf of 1.5 V. When short circuited, it gives a current of 3 A. The internal resistance of cell is ?

A) 2 Ω
B) 0.2 Ω
C) 0.5 Ω
D) 4.5 Ω

... Answer is C)
Watch the Video .

50. Base load of a power station stands for ?

A) 12-24 hours/day
B) 2-4 hours/day
C) 8-12 hours/day
D) 4-8 hours/day

... Answer is A)
Watch the Video .

51. Humans are more vulnerable to electric shock current at ?

A) 50 Hz
B) 48 Hz
C) 40 Hz
D) 45 Hz

... Answer is A)
Watch the Video .

52. The Ta Vs Ia graph of a dc series motor is A ?

A) Straight line throughout
B) Parabola up to full load and a straight line at over load
C) Parabola from no load to over load
D) Parabola throughout

... Answer is B)
Watch the Video .

53. During the resistance welding, the heat produced at the joint is proportional to ?

A) Volt-Ampere
B) Voltage
C) current
D) I2R

... Answer is D)
Watch the Video .

54. In the Maxwell bridge as shown in the figure below the values of resistance Rx and inductance Lx of a coil are to be calculated after balancing the bridge. The component values are shown in the fig at balance. The values of Rx and Lx will respectively be ?

A) 75 ohm, 150 mH
B) 75 ohm, 75mH
C) 37.5 ohm, 75 mH
D) 375 ohm, 75 mH

... Answer is D)
Watch the Video .

55. The electric driver posses the following drawback ?

A) not available with various rating
B) requires a continuous power supply
C) not adoptable to various environments
D) requires hazardous fuel requirement

... Answer is B)
Watch the Video .

56. A CRO Screen has ten divisions on the horizontal scale. If a voltage signal 5 sin (314t+450) is examined with a line base setting of 5 msec/div, the number of cycle of signal displayed on the screen will be ?

A) 0.5 cycle
B) 10 cycles
C) 2.5 cycle
D) 5 cycles

... Answer is C)
Watch the Video .

57. An eight pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 rpm by a prime mover in the opposite direction of revolving magnetic field. The frequency of rotor current is ?

A) 60 Hz
B) 200 Hz
C) 120 Hz
D) 180 Hz

... Answer is D)
Watch the Video .

58. With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be ?

A) High resistance
B) Infinite
C) Open
D) Low resistance

... Answer is D)
Watch the Video .

59. The magnitude of AT required to establish a given value of flux in the air gap will be much greater than that required for Iron part of a magnetic circuit, because ?

A) air has the lowest relative permeability
B) iron has the lowest permeability
C) air is a gas
D) air is a good conductor of magnetic flux

... Answer is A)
Watch the Video .

60. Electrical Resistivity p is ?

A) High for copper and low for alloy
B) High for copper as well as for alloy
C) Low for copper as well as for alloy
D) Low for copper and high for alloy

... Answer is D)
Watch the Video .

61. To prepare a P type semiconducting material the impurities to be added to silicon are ?

A) Arsenic, Antimony
B) Gallium, Arsenic
C) Gallium, Phosphorous
D) Boron, Gallium

... Answer is D)
Watch the Video .

62. The minimum area of cross section of a three and half core cable should be ?

A) 30 cm2
B) 50 cm2
C) 40 cm2
D) 60 cm2

... Answer is B)
Watch the Video .

63. A lissajous pattern on an oscilloscope has 5 horizontal tangencies and 2 vertical tangencies. The frequency of the horizontal input is 100 Hz. The frequency of the vertical input will be ?

A) 4000 Hz
B) 2500 Hz
C) 40 Hz
D) 5000 Hz

... Answer is C)
Watch the Video .

64. In dc operation of flourescent tube, the life of the tube ?

A) May increase of decrease
B) Decreases by about 80% as that with ac operation
C) Increases by about 80% as that with ac operation
D) Remain same

... Answer is B)
Watch the Video .

65. A circuit breaker is rated as follows: 1500 A, 33 KV, 3 sec, 3-phase oil circuit breaker. Determine the making current ?

A) 110 KA
B) 35 KA
C) 1.5 KA
D) 89 KA

... Answer is D)
Watch the Video .

66. An RLC series circuit has R=10Ω, L=2H. What value of capacitance will make the circuit critically damped ?

A) 0.08F
B) 0.2F
C) 0.4F
D) 0.02F

... Answer is A)
Watch the Video .

67. If span length is doubled with no change in other factors, the sag of the line will become ?

A) 2 times
B) times
C) 4 times
D) 0.5 time

... Answer is C)
Watch the Video .

68. What is the power consumed by the resistor of 20 Ω connected across 100 V source ?

A) 300 W
B) 500 W
C) 50 W
D) 100 w

... Answer is B)
Watch the Video .

69. The area of the hysteresis loop will be least for one of the following materials. It is ?

A) Silicon steel
B) soft iron
C) hard steel
D) wrought iron

... Answer is A)
Watch the Video .

70. The acceptable value of grounding resistance for domestic applications is ?

A) 0.5 Ω
B) 1.5 Ω
C) 2 Ω
D) 1 Ω

... Answer is D)
Watch the Video .

71. An alternator is supplying a load of 300 kw at a power factor of 0.6 lagging. If the power factor is raised to unity, how many more kw canalternator supply ?

A) 300 kw
B) 100 kw
C) 150 kw
D) 200 kw

... Answer is D)
Watch the Video .

72. When a series RL circuit is connected to a voltage source V at t = 0, the current passing through the inductor L at t = 0+ is ?

A) infinite
B) V R
C) V L
D) zero

... Answer is D)
Watch the Video .

73. Creeping in a single phase induction type energy meter may be due to ?

A) Over voltage
B) Vibrations
C) Over compensation for friction
D) All of the given options

... Answer is D)
Watch the Video .

74. Synchronous impedance method of finding voltage regulation of an alternator is called pessimistic method because ?

A) It gives regulation value higher than its actual found by direct loading
B) armature reaction is wholly magnetising
C) it is simplest to perform and compute
D) it gives regulation value lower than its actual found by direct loading

... Answer is A)
Watch the Video .

75. For the circuit shown in figure, the Norton's equivalent current source at terminals A & B is given by ?

A) 16 ∠36.86 A
B) 10 ∠0 A
C) 14 ∠36.86 A
D) 20 ∠0A

... Answer is B)
Watch the Video .

76. Each of the following statements regarding a shaded pole motor is true accept ?

A) it has very poor power
B) its direction of rotation is from unshaded to shaded portion of poles
C) it has very poor efficiency
D) it has high starting torque.

... Answer is B)
Watch the Video .

77. A linear circuit is one whose parameters ?

A) change with change in current
B) change with change in voltage
C) do not change with voltage and current
D) None of the options

... Answer is C)
Watch the Video .

78. The reactive power generated by a synchronous alternator can be controlled by ?

A) changing the alternator speed
B) changing the prime move input
C) changing the terminal voltage
D) changing the field excitation

... Answer is D)
Watch the Video .

79. For cleat wiring and 250 volts supply, the cables will be placed_____a part centre to centre for single core cables. ?

A) 4.5 cm
B) 2.5 cm
C) 3 cm
D) 4 cm

... Answer is B)
Watch the Video .

80. The errors in Current Transformers can be reduced by designing them with ?

A) using large cross section for both Primary and secondary winding conductors.
B) using Primary and secondary winding as close to each other as possible
C) high permeability and low loss core materials, avoiding any joints in the core and also keeping the flux density to a low value.
D) All of the given options

... Answer is C)
Watch the Video .

81. The aluminium conductor of size_____is used for a subcircuit in dimestic wiring. ?

A) 1 mm 1.8
B) 1 mm 2.24
C) 1 mm 1.4
D) 1 mm 1.2

... Answer is C)
Watch the Video .

82. Silicon has a preference in IC technology because ?

A) of the availability of nature oxide Sio
B) it is an elemental semiconductor
C) it is an indirect semiconductor
D) it is a covalent semiconductor

... Answer is A)
Watch the Video .

83. The motor used on small lathes is usually ?

A) D.C. shunt motor
B) Single phase capacitor run motor
C) 3-phase synchronons motor
D) M S

... Answer is B)
Watch the Video .

84. Which of the following notor is non-self starting ?

A) Squirrel cage induction motor
B) DC series motor
C) Synchronous motor
D) Slip ring induction motor

... Answer is C)
Watch the Video .

85. The internal resistance of a voltage source is 10Ω and has 10volts at its terminals. Find the max. power that can be transferred to the load. ?

A) 0.25 W
B) 2.5 W
C) 5 W
D) 25 W

... Answer is C)
Watch the Video .

86. The voltage across the 1kΩ resistor of the network shown in the given figure is ?

A) 1 V
B) 2 V
C) 4 V
D) 6 V

... Answer is B)
Watch the Video .

87. For the circuit shown below, find the resistance between points P & Q. ?

A) 1 Ω
B) 2 Ω
C) 3 Ω
D) 4 Ω

... Answer is B)
Watch the Video .

88. The e.m.f. induced in a coil of N turns is given by ?

A) N m
B) R K
C) A S
D) M S

... Answer is A)
Watch the Video .

89. The permissible voltage drop from supply terminal to any point on the wiring system should not exceed ?

A) 4%+1 volt
B) 1%+1volt
C) 3%+1volt
D) 2%+1volt

... Answer is D)
Watch the Video .

90. The unit for permeability is ?

A) AT Wb
B) Wb At m×
C) At m
D) Wb

... Answer is B)
Watch the Video .

91. A dc voltmeter has a sensitivity of 1000 Ω/ volt. When it measures half full scale in 100V range, the current through the voltmeter will be ?

A) 50 mA
B) 1 mA
C) 0.5 mA
D) 100 mA

... Answer is A)
Watch the Video .

92. If a dynamometer type wattmeter is connected in an ac circuit, the power indicated by the wattmeter will be ?

A) Instantaneous power
B) Peak power
C) Volt ampere product
D) Average power

... Answer is D)
Watch the Video .

93. If in an R-L-C series circuit, the frequency is below the resonant frequency, then ?

A) Xc = XL
B) Xc < XL
C) Xc > XL
D) None of the options

... Answer is C)
Watch the Video .

94. The unit of luminous flux is ?

A) lux
B) candela
C) steradian
D) lumen

... Answer is D)
Watch the Video .

95. Three wattmeter method of power measurement can be used to measure power in ?

A) unbalanced Circuits
B) Balanced Circuits
C) Both balanced and unbalanced Circuits
D) None of the options

... Answer is C)
Watch the Video .

96. For painful shock, what is the range of electric shock current at 50Hz ?

A) 0-1 mA
B) 0-3 mA
C) 3-5 mA
D) 5-10 mA

... Answer is D)
Watch the Video .

97. A resistor is connected across a 50 V source. The current in the resistor if the colour code is red, orange, orange, silver is ?

A) 2 mA
B) 2.2 mA
C) 21.4 mA
D) 214 mA

... Answer is B)
Watch the Video .

98. Thevenin's theorem cannot be applied to ?

A) active circuit
B) linear circuit
C) nonlinear circuit
D) passive circuit

... Answer is C)
Watch the Video .

99. One sine wave has a period of 2 ms, another has a period of 5 ms, and other has a period of 10 ms. Which sine wave is changing at a faster rate ?

A) sine wave with period 5 ms
B) sine wave with period 2 ms
C) sine wave with period of 10 msec
D) all are at the same rate

... Answer is B)
Watch the Video .

100. A bar of Iron i cm2 in cross section has 10-4 wb of Magnetic flux in it, If µr = 2000. What is the Magnetic field intensity in the bar ?

A) 398 AT M
B) 398×10-4 AT M
C) 796×103 AT M
D) 398×104 AT M

... Answer is A)
Watch the Video .