SSC Junior Engineer Electrical Online Exam 2017 CPWD/CWC/MES Electrical Engineering 2-03-2017 Morning

1. Which effect of the electric currents is utilized in a filament lamp ?

A) The magnetic effect
B) The heating effect
C) The Chemical effect
D) The collision ionization of the gases

... Answer is B)
Explanation will provide as soon as possible.

2. Which of the following statements about electric voltage is true ?

A) Voltage causes current to flow
B) Voltage is the directed movement of electrons
C) Voltage in not always needed to cause the flow of current
D) Voltage is the irregular movement of electrons

... Answer is A)
Explanation will provide as soon as possible.

3. A material which is slightly repelled by a magnetic field is known as ?

A) Ferro-magnetic Material
B) Paramagnetic material
C) Diamagnatic material
D) None of these

... Answer is C)
Explanation will provide as soon as possible.

4. Internal resistance per cell of Lead Acid cell is always ?

A) more than Edision cell
B) less than Edision cell
C) equal to Edision cell
D) None of these

... Answer is B)
Explanation will provide as soon as possible.

5. Mica capacitors are charactersied by all of the following except ?

A) Accurate value
B) Low losses
C) Stable operation
D) Low leakage resistance

... Answer is D)
Explanation will provide as soon as possible.

6. In a capacitor, the electric charge is stored in ?

A) Metal plates
B) Dielectric
C) Dielectric as well as metal plates
D) Neither dielectric nor metal plates

... Answer is B)
Explanation will provide as soon as possible.

7. When a dielectric is placed in an electric field, the field strength ?

A) Decreases
B) Increases
C) Remain unchanged
D) Reduces to zero

... Answer is A)
Explanation will provide as soon as possible.

8. The maximum value of potential gradient in a cable occurs in ?

A) Insulation
B) Outer sheath
C) Conductor
D) None of these

... Answer is C)
Explanation will provide as soon as possible.

9. A six dot mica capacitor color coded, white, red, green brown, red and yellow has the capacitance value of ?

A) 925 pF
B) 250 pF
C) 124 pF
D) 25 pF

... Answer is A)
Explanation will provide as soon as possible.

10. A charge exists on a conductor. The best way to remove this charge is to ?

A) Ground the conductor
B) Isolate the conductor from other charges
C) Create Vacuum around the conductor
D) None of these

... Answer is A)
Explanation will provide as soon as possible.

11. A current of 5A flows through a conductor against a potential difference of 200V. The power dissipated will be ?

A) 2000W
B) 1.1kW
C) 1000W
D) 100W

... Answer is C)
Explanation will provide as soon as possible.

12. Energy (in units) consumed by a heater of rating 1000W by operating if for a period of 2 hours will be ?

A) 1.5
B) 2
C) 2.5
D) 4

... Answer is B)
Explanation will provide as soon as possible.

13. Which of the statements about the circuit shown in the figure is true ?

A) The voltage sources V1 and V2 are connected in series
B) The resistances R1 and R2 are connected in parallel
C) The voltage sources V1 and V2 connected in parallel
D) The resistance R1, R2 and R3 are connected in parallel

... Answer is C)
Explanation will provide as soon as possible.

14. Which of the following formula is used to calculate the total resistance R of the circuit shown below ?

A) R = (R1×R2×…×Rn)/(R1+R2+…+Rn)
B) R = (1/R1) + (1/R2) +…+ (1/Rn)
C) 1/R = (1/R1) + (1/R2) +…+ (1/Rn)
D) R = R1 + R2 + …+ Rn

... Answer is C)
Explanation will provide as soon as possible.

15. Copper has less resistance than aluminum and has greater tensile strength than aluminium. To work, copper proves an excellent material as compared to aluminium. In spite of this, nowadays aluminium is extensively used in transmission and distribution of power supply because ?

A) It is cheaper than copper
B) Copper is not available
C) It is light in weight
D) It is easily available

... Answer is A)
Explanation will provide as soon as possible.

16. The resistance R1 and R2 are connected in parallel. The ratio of values of resistance R1:R2 is 4:1. The current in R1:R2 will be equal to ?

A) 4:1
B) 1:4
C) 1:1
D) 4:4

... Answer is B)
Explanation will provide as soon as possible.

17. Kirchhoff's law states that in a closed loop of a circuit ?

A) That total current, algebraically summed is zero
B) ponents is zero
C) the algebraic sum of the potential differences is zero
D) None of these

... Answer is C)
Explanation will provide as soon as possible.

18. Does the electric current always produce a magnetic field ?

A) No, only large currents produce a magnetic field
B) No, a magnetic field is produced only in the presence of an iron core
C) No, a magnetic field is produced only in the presence of a coil
D) Yes, the electric current always produce a magnetic field

... Answer is D)
Explanation will provide as soon as possible.

19. Comparing a magnetic circuit with an electric circuit the equivalent for the magnetic flux is ?

A) The conductivity of the line
B) The current in the lines
C) The resistance of the load
D) The voltage of the source

... Answer is B)
Explanation will provide as soon as possible.

20. How can the magnetic flux in the magnetic circuit shown in the figure be increased ?

A) By increasing the magneto-motive force
B) By decreasing the magneto-motive force
C) By marking an air gap in the core
D) By reversing the direction of the current

... Answer is A)
Explanation will provide as soon as possible.

21. In an RC-coupled Common Emitter amplifier ?

A) coupling capacitance affects the hf response and bypass capacitance affects the If response only
B) both coupling and bypass capacitance affect the If response only
C) both coupling and bypass capacitance affect the hf response only
D) coupling capacitance affects the If response and the bypass capacitance affects affects the hf response

... Answer is D)
Explanation will provide as soon as possible.

22. The threshold voltage of an n-channel MOSFET can be increased by ?

A) reducing the channel doping concentration
B) icreasing the channel doping concentration
C) reducing the gate oxide thickness
D) reducing the channel length

... Answer is A)
Explanation will provide as soon as possible.

23. The transit time of the current carriers through the channel of an FET decides its ?

A) On/off
B) Dynamic
C) Switching
D) Load

... Answer is C)
Explanation will provide as soon as possible.

24. The drift velocity of electrons, in silicon ?

A) is independent of the electric field
B) is proportional to the electric field for all values of electric field
C) increases linearly with electric field at low values of electric field and gradually saturates at higher values of electric field
D) increases at low values of electric field and decreases at high values of electric field exhibiting negative differential resistance

... Answer is C)
Explanation will provide as soon as possible.

25. Thermal runaway in a transistor biased in the active range is due to ?

A) changes in β which increase with temperature
B) heating the transistor
C) change in reverse collector saturation current due to rise in temperature
D) base emitter voltage VBE which decreases with rise in temperature

... Answer is C)
Explanation will provide as soon as possible.

26. An external resistance added in the field of a d.c. shunt generator will ?

A) increase the speed of the generator
B) increase the voltage of the generator
C) decrease the voltage of the generator
D) increase the power delivered

... Answer is C)
Explanation will provide as soon as possible.

27. The torque of a motor is ?

A) force (in N-m) acting on the motor
B) the product of tangential force on the rotor and its radius
C) the electrical power in kW
D) the power given to load being driven by the motor

... Answer is B)
Explanation will provide as soon as possible.

28. The terminal board of a motor is as shown in the diagram. Which type of motor is this ?

A) A compound motor with commutating pole winding
B) A shunt motor with commutating pole widing
C) A shunt motor without commutating pole winding
D) A series motor with commutating pole winding

... Answer is D)
Explanation will provide as soon as possible.

29. The speed of a series motor at no load is ?

A) infinity
B) 3000rpm
C) 3600rpm
D) Zero

... Answer is A)
Explanation will provide as soon as possible.

30. The field flux of a d.c. motor can be controlled to achieve ?

A) The speed is lower than rated speed
B) The speed is higher than rated speed
C) The speed is at rated speed
D) None of these

... Answer is B)
Explanation will provide as soon as possible.

31. What will happen if the supply terminals of d.c. shunt motor are interchanged ?

A) Motor will run at its normal in the same direction as it was running
B) Motor will stop
C) The direction of rotation will reverse
D) Motor will run at a speed lower than the normal speed in the same direction

... Answer is A)
Explanation will provide as soon as possible.

32. Resistivity of a semiconductor depends on ?

A) the length of the semiconductor specimen
B) cross-sectional area of the semiconductor specimen
C) volume of the semiconductor specimen
D) the atomic nature of the semiconductor

... Answer is D)
Explanation will provide as soon as possible.

33. A germanium atom contains ?

A) four valence electrons
B) six valence electrons
C) four protons
D) six protons

... Answer is A)
Explanation will provide as soon as possible.

34. A hole is the vacancy created when ?

A) a free electron moves on application of electric field
B) an electron breaks its covalent band
C) an atomic core moves
D) an electron reverts from conduction band to valence band

... Answer is B)
Explanation will provide as soon as possible.

35. Forbidden energy gap between valence band and conduction band is least in the case of ?

A) mica
B) pure silicon
C) pure germanium
D) impure silicon

... Answer is D)
Explanation will provide as soon as possible.

36. Donor impurity atom in a semiconductor result in new ?

A) wide energy band
B) narrow energy band
C) discrete energy level just below conduction level
D) discrete energy level just above valence level

... Answer is C)
Explanation will provide as soon as possible.

37. A p-type semiconductor is ?

A) positively charged
B) negatively charged
C) electrically neutral
D) not used in semiconductor devices

... Answer is A)
Explanation will provide as soon as possible.

38. Change of carrier concentration along the length of a semiconductor is called ?

A) mobility
B) diffusion
C) concentration gradient
D) drift

... Answer is C)
Explanation will provide as soon as possible.

39. In a semiconductor, movement of charge carriers under influence of an electric field is called ?

A) diffusion
B) drift
C) mobility
D) conductivity

... Answer is B)
Explanation will provide as soon as possible.

40. In pure silicon, major part of the drift current in due to free electrons because ?

A) there are more free electrons than holes
B) free electrons are in the valence band
C) mobility of electrons is greater than the mobility of holes
D) diffusion constant of electrons in greater than that of holes

... Answer is C)
Explanation will provide as soon as possible.

41. Semiconductor may be made n-type by adding donor impurity ?

A) during zone refining
B) during chemical purification
C) during crystal pulling
D) befor purification process

... Answer is C)
Explanation will provide as soon as possible.

42. A 35V-source is connected to a series circuit at 600 ohms and R as shown. If a voltmeter at internal resistance 1.2 kilo ohms is connected across 600 ohm resistor it reads 5V. The value of R is ?

A) 1.2 kΩ
B) 2.4 kΩ
C) 3.6 kΩ
D) 7.2 kΩ

... Answer is B)
Explanation will provide as soon as possible.

43. In the circuit shown, the value at I is ?

A) 1A
B) 2A
C) 4A
D) 8A

... Answer is B)
Explanation will provide as soon as possible.

44. When the plate area of a parallel plate capacitor is increased keeping the capacitor voltage constant, the force between places ?

A) increases
B) decreases
C) remains constant
D) may increase or decrease on the metal making up the plates

... Answer is A)
Explanation will provide as soon as possible.

45. Energy stored in a capacitor over a cycle when excited by an a.c. source is ?

A) same as that due to a d.c. source at equivalent magnitude
B) half of at due to a d.c. source at equivalent magnitude
C) zero
D) None of these

... Answer is c)
Explanation will provide as soon as possible.

46. Inside a hollow conducting spere, electric field ?

A) is zero
B) is a non-zero constant
C) changes with the magnitude of the charge given to the conductor
D) changes with distance from the centre of the sphere

... Answer is A)
Explanation will provide as soon as possible.

47. In the network shown in the given figure, if the voltage V at the time considered is 20V, then dV/dt at that time will be ?

A) 1V/s
B) 2V/s
C) -2V/s
D) zero

... Answer is B)
Explanation will provide as soon as possible.

48. The resistance of a strip of copper of rectangular cross-section is 2Ω. A metal of resistivity twice that of copper is coated on its upper surface to a thickness equal to that of copper strip. The resistance of composite strip will be ?

A) 6Ω
B) 4/3Ω
C) 3/2Ω
D) 3/4Ω

... Answer is B)
Explanation will provide as soon as possible.

49. Two coupled coils of L1 = 0.8H and L2 = 0.2H have a coupling coefficiecnt k = 0.9. The mutual inductance M is ?

A) 0.144H
B) 0.23H
C) 0.36H
D) 0.43H

... Answer is C)
Explanation will provide as soon as possible.

50. A coil with large distributed capacitance has a ?

A) high Q
B) low Q
C) low resonant frequency
D) high resonant frequency

... Answer is B)
Explanation will provide as soon as possible.

51. A megohmmeter reading of zero or low ohms is indicated between the stator winding and motor frame. The winding is ?

A) open
B) series connected
C) grounded
D) cross connected

... Answer is C)
Explanation will provide as soon as possible.

52. A capacitor motor has difficulty of starting. What is the probable cause ?

A) Reversed magnetic field
B) Shorted commutator segments
C) Shorted windings
D) All options are correct

... Answer is C)
Explanation will provide as soon as possible.

53. To a highly inductive circuit, a small capacitance is added in series. The angle between voltage and current will ?

A) increase
B) decrease
C) remain nearly the same
D) become indeterminant

... Answer is B)
Explanation will provide as soon as possible.

54. After the starting winding is disconnected from the circuit, the motor continues to run only on the ?

A) squirrel-cage winding
B) running winding
C) magnetic winding
D) compensating winding

... Answer is B)
Explanation will provide as soon as possible.

55. If the rotor of a 3-phase induction motor is assumed purely resistve, then electromagnetic torque is ?

A) minimum with load angle of 90 degree
B) minimum with load angle of 0 degree
C) optimum with load angle of 90 degree
D) optimum with load angle of 90 degree

... Answer is #)
Explanation will provide as soon as possible.

56. The commutator in a repulsion motor provides ?

A) armature windings
B) stator windings
C) short-circuiting device
D) starting-winiding

... Answer is A)
Explanation will provide as soon as possible.

57. Which of the following motors has a squirrelcage winding embedded in the armature under the regular winding ?

A) compound motor
B) repulsion-start, induction-run motor
C) repulsion motor
D) repulsion-induction motor

... Answer is D)
Explanation will provide as soon as possible.

58. A moving-iron meter will operate on ?

A) A-C circuit only
B) D-C ciruit only
C) either A-C or D-C circuit
D) A-C or D-C when a rectifier is used

... Answer is C)
Explanation will provide as soon as possible.

59. Electro dynamometers are used extensively for the measurement of ?

A) magnetic lines of force
B) resistivity
C) capacitor networks
D) power

... Answer is D)
Explanation will provide as soon as possible.

60. If a wattmeter is used in a circuit it is safe voltage or current rating is exceeded, the meter will ?

A) not be affected
B) operated erratically
C) immediately peg the pointer
D) not indicate the overload

... Answer is D)
Explanation will provide as soon as possible.

61. A varmeter is used to indicate the ?

A) internal A-C overloads
B) out-of-phase voltage change
C) amount of reactive change
D) amount of true power

... Answer is C)
Explanation will provide as soon as possible.

62. Which of the following does a power factor meter indicate ?

A) Continuos power
B) Power difference between phases
C) The current is leading or lagging the lagging the voltage
D) Reactive and useful power

... Answer is C)
Explanation will provide as soon as possible.

63. What three electrical quantities can be measured by a multimeter ?

A) Voltage, current and watts
B) Voltage, current and resistance
C) Voltage, current and amperes
D) Voltage, watts and VARs

... Answer is B)
Explanation will provide as soon as possible.

64. A multimeter uses different multipliers to increase the ?

A) current range
B) voltage range
C) resistance range
D) impedance range

... Answer is B)
Explanation will provide as soon as possible.

65. When a Wheatstone bridge is balanced, the galvanometer reads ?

A) zero current
B) maximum current
C) zero voltage
D) maximum voltage

... Answer is A)
Explanation will provide as soon as possible.

66. What type of a bridge circuit is used to measure inductance and capacitance ?

A) Wheatstone bridge
B) D-C bridge
C) A-C bridge
D) A-C, D-C bridge

... Answer is C)
Explanation will provide as soon as possible.

67. A bulb-type voltage tester is recommended only for circuits at or under how many volts ?

A) 120 volts
B) 240 volts
C) 480 volts
D) 600 volts

... Answer is A)
Explanation will provide as soon as possible.

68. The amortisseur winding in a synchronous motor ?

A) provides starting torque only
B) provides starting torque and eliminates hunting
C) improves the power factor of the machine
D) None of these

... Answer is A)
Explanation will provide as soon as possible.

69. When a synchronous motor is started, the field winding is initially ?

A) short circuited
B) open circuited
C) excited by a d.c source
D) None of these

... Answer is A)
Explanation will provide as soon as possible.

70. If the excitation and terminal voltage of synchronous motor are kept constant and the load is increased then ?

A) armature current increases and power factor becomes more leading
B) armature current decreases and power factor becomes power leading
C) armature current increases and power factor becomes more lagging
D) None of these

... Answer is C)
Explanation will provide as soon as possible.

71. In a synchronous motor ?

A) the speed of rotor mmf is slightly less than the speed of stator mmf
B) the rotor mmf and stator mmf are stationary with respect to each other
C) the speed to rotor mmf is slightly more than the speed of stator mmf
D) None of these

... Answer is B)
Explanation will provide as soon as possible.

72. Under short circuit conditions, the power factor of an alternator is ?

A) unity
B) about 0.6 lagging
C) almost zero lagging
D) None of these

... Answer is C)
Explanation will provide as soon as possible.

73. The rated voltage of alternators used in power stations is usually ?

A) 400 kV
B) 132 kV
C) 66 kV
D) 11 kV

... Answer is D)
Explanation will provide as soon as possible.

74. A transformer has a core loss of 64W and copper loss of 144W, when it is carrying 20% overload current. The load at which this transformer will operate at the maximum efficiency ?

A) 44%
B) 66%
C) 80%
D) 120%

... Answer is C)
Explanation will provide as soon as possible.

75. Two transformers operating in parallel will share the load depending upon their ?

A) ratings also
B) efficiency also
C) leakage resistance
D) None of these

... Answer is A)
Explanation will provide as soon as possible.

76. Which of the following transformers is smallest ?

A) 1 kVA, 50Hz
B) 1 kVA, 200Hz
C) 1 kVA, 400Hz
D) 1 kVA, 600Hz

... Answer is D)
Explanation will provide as soon as possible.

77. The short-circuit test in a transformer is used to determine ?

A) copper loss at any load
B) iron loss at any load
C) eddy-current loss
D) hystersis loss

... Answer is A)
Explanation will provide as soon as possible.

78. Under heavy loads, transformer efficiency is comparatively low beacause ?

A) secondary output is much less as compared to primary input
B) voltage drops both in primary and secondary becomes large
C) copper loss becomes high in proportion to the output
D) iron loss is increased considerably

... Answer is C)
Explanation will provide as soon as possible.

79. In relation to a transformer the ratio 20:1 indicates that ?

A) There are 20 turns on primary and one turn on secondary
B) Secondary voltage is 1/20th of primary voltage
C) Primary current is 20 times greater than secondary current
D) For every 20 turns on primary, there is one turn on seconday

... Answer is D)
Explanation will provide as soon as possible.

80. Overhead lines generally use ?

A) copper conductors
B) all aluminium conductors
C) ACSR conductors
D) None of these

... Answer is C)
Explanation will provide as soon as possible.

81. High voltage transmission lines use ?

A) pin insulators
B) suspension insulators
C) shackle insulators
D) None of these

... Answer is B)
Explanation will provide as soon as possible.

82. The criterion for selection of size of conductor for a feeder is ?

A) Voltage drop
B) Temperature rise
C) Corona loss
D) Radio interference

... Answer is B)
Explanation will provide as soon as possible.

83. The weight of a locomotive is 120 tonnes. If the axle load is not to exceed 20 tonnes, the number of axles required is ?

A) 3
B) 7
C) 12
D) None of these

... Answer is D)
Explanation will provide as soon as possible.

84. A lighting sub-circuit has 100W lamps. If the rated current of the fused in this circuit is 5A, the maximum number of light points on this circuit without violating regulations and safety should be ?

A) 8
B) 9
C) 14
D) 16

... Answer is A)
Explanation will provide as soon as possible.

85. What is the minimum permissible size of the earth continuity conductor ?

A) 13 sq.mm
B) 11 sq.mm
C) 9 sq. mm
D) 6 sq.mm

... Answer is D)
Explanation will provide as soon as possible.

86. The function of the depolarizer in a carbonzinc cell is that ?

A) It converts the produced hydrogen into water
B) It prevents the fast chemical action on the zinc container
C) It synthesis the decomposed electrolyte
D) It absorbs the oxygen produced in the cell

... Answer is A)
Explanation will provide as soon as possible.

87. Midway between two equal and similar charges, a third equal and similar charge is placed. Then this third charge will ?

A) Be in unstable equilibrium
B) Not be in equilibrium
C) Remain in stable equilibrium
D) Will move out of the field to influence the two charges

... Answer is C)
Explanation will provide as soon as possible.

88. Two parallel conductors are carrying currents in the same direction. Which of the following statements is correct ?

A) There is a repelling force
B) There is an attracting force between the conductors
C) The force increases when the current is decreased
D) The force increases when the distance between the conductors is increased

... Answer is B)
Explanation will provide as soon as possible.

89. Is it possible to prevent by very fast operation of the switch the switching spark produce during switching off of an inductance ?

A) No, the faster the circuit is opened, the higer is the self-induced voltage
B) Yes, as long as the circuit is opened fast enough
C) Yes, as long as the switch can withstand the high switching speed
D) Yes, if the current is less than 50A

... Answer is A)
Explanation will provide as soon as possible.

90. A contactor coil is designed for 220V, D.C. What happens if it is connected to 220V, A.C. ?

A) A too large current is drawn by the coil and it is destroyed
B) A too small current is drawn by the coil and the operation of the contactor is no longer certain
C) The permanent magnet of the magnetic system is demagnetized
D) The coil insulation is quickly damaged by the alternating voltage

... Answer is B)
Explanation will provide as soon as possible.

91. Which of the following is true about coefficient of adhesion ?

A) It is same on a.c. and d.c. traction systems
B) It is high in case of d.c. traction and low in a.c. traction
C) It is low in case of a.c. traction and high in d.c. traction
D) None of these

... Answer is C)
Explanation will provide as soon as possible.

92. Which of the following indicates the usual specific energy consumption for suburban train service ?

A) 18 to 25 watt-hours per tonne km
B) 50 to 75 watt-hours per tonne km
C) 125 to 150 watt-hours per tonne km
D) 155 to 200 watt-hours per tonne km

... Answer is B)
Explanation will provide as soon as possible.

93. Which of the following is the reason for the sound produced by horn in automobiles ?

A) Magnetostriction
B) Vibrating diaphragm
C) Moving coil
D) Oscillating coil

... Answer is B)
Explanation will provide as soon as possible.

94. How is the miniature lamps on automobiles used ?

A) It is used as tail lamp
B) It is used as dash board lamp
C) It is used as side lamp
D) All options are corrct

... Answer is D)
Explanation will provide as soon as possible.

95. For low and medium power derives, where speed control is not required, the motor that is recommended is ?

A) Synchronous motor
B) Squirrel cage induction motor
C) Double cage induction motor
D) Three-phase series motor

... Answer is B)
Explanation will provide as soon as possible.

96. Why is the energy consumption in propelling the train required for?
1- Acceleration
2- Work against gravity while moving up the gradient
3- Work against the resistance to motion

A) Only 1 and 2
B) Only 2 and 3
C) 1,2 and 3
D) Only 1 and 3

... Answer is C)
Explanation will provide as soon as possible.

97. Which of the follwing is true about low frequency operation of a.c. series motor ?

A) It improves its commutation property but affects adversely the p.f. and efficiency
B) It improves its commutation property p.f. and efficiency
C) It affects adversely commutation but improves p.f. and efficiecny
D) None of these

... Answer is B)
Explanation will provide as soon as possible.

98. Two locomotives having identical tractiveeffort-slip characteristic haul a heavy train. The locomotive with larger diameter shares ?

A) Larger tractive effort
B) Smaller tractive effort
C) Equal tractive effort
D) None of these

... Answer is A)
Explanation will provide as soon as possible.

99. Which of the following is the range of the efficiency of a welding motor generator ?

A) 30 to 45%
B) 50 to 60%
C) 80 to 90%
D) 90 to 95%

... Answer is B)
Explanation will provide as soon as possible.

100. The 12mm steel plates are to be welded using arc welding. Electrode of No. 8 is to be used. What will be the current requirement ?

A) 10A
B) 50A
C) 100A
D) 150A

... Answer is D)
Explanation will provide as soon as possible.