(Paper) RRB ALP Paper Stage-2 : Exam Paper & Answer Key Held on 23-Jan-2019 Shift-3 (Electrician)
(Paper) RRB ALP Paper Stage-2 : Exam Paper &
Answer Key Held on 23-Jan-2019 Shift-3
(Electrician)
Q1. For an ideal transformer,if I2/I1 =2 and E2 =100,E1 Will be:
a. 25
b. 100
c. 200
d. 50
Q2. If the voltage drop across individual resistors R1 R2 R3 connected to a battery are 10 V, 20 V and 30 V respectively, then the total battery voltage is:
a. 30 V
b. 60 V
c. Zero
d. 20 V
Q3. In a current transformer, the number of primary turns is always:
a. Zero
b. Greater than the number of secondary turns
c. Less than the number of secondary turns
d. Equals the number of secondary turns
Q4. The average power dissipated in a pure inductor is:
a. Proportional to applied voltage
b. Infinite
c. Zero
d. Proportional to value of inductance
Q5. Which of the following protects the cable against mechanical injury?
a. Armouring
b. Core
c. Sheath
d. Bedding
Q6. The complement of (A.B) is:
a. A.B
b. Complement of A + complement of B
c. Complement of A, complement of B
d. A + B
Q7. Choppers are _______ converters.
a. DC to DC
b. AC to DC
c. DC to AC
d. AC to AC
Q8. A circuit in which resistance are connected end to end that there is only one path for current to flow is called a _____.
a. Parallel circuit
b. Series circuit
c. Neither series nor parallel circuit
d. Series-parallel circuit
Q9. Which of the following motors is identical to an induction motor?
a. DC compound motor
b. DC series motor
c. Synchronous motor
d. Asynchronous motor
Q10. In an electrical machine, the core is laminated to reduce:
a. Copper loss
b. Eddy current loss
c. Hysteresis loss
d. Friction loss
Q11. Three Identical bulbs are connected in series and these together dissipate power ‘M’. If now the bulbs are connected in parallel, then the power dissipated will be:
a. 3M
b. M/9
c. M/3
d. 9M
Q12. An SCR consists of:
a. One PN junction
b. Three PN junction
c. Two PN junction
d. No PN junction
Q13. If a resistance of 10 ohms and a capacitance of 1 μΩF is connected across a 230 V, 50 Hz AC supply, the capacitive reactance of the circuit is:
a. 3.183Ω
b. 3183Ω
c. 0.0318Ω
d. 31.83Ω
Q14. Iron loss of a transformer can be measured by:
a. Frequency meter
b. Unity power factor watt meter
c. Any type of watt meter
d. Low power factor wattmeter
Q15. The resistance of an ideal voltmeter is:
a. Infinite
b. Very low
c. Zero
d. Very large
Q16. The form factor of AC wave is defined as the ratio of:
a. Peak value to instantaneous value
b. Peak value to average value
c. RMS value to average value
d. RMS value to instantaneous value
Q17.Q38. A car covers 400 m in 20 seconds. Find the average speed (in km/hr) of the car.
a. 36
b. 72
c. 108
d. 124
Q18. In a series R-C circuit, the AC current is:
a. Leading the applied voltage
b. In phase with the applied voltage
c. Out of phase with applied voltage
d. Lagging behind the applied voltage
Q19. The unit of sensitivity of an instrument is:
a. ohm/volt
b. volt/ohm
c. ampere/sec
d. Volt-amp
Q20. Which among the following, remains the same in a series circuit?
a. Current
b. Power
c. Voltage
d. Resistance
Q21. From the following parameters, which parameter’s variation will not affect the capacitance of the capacitor?
a. Thickness of the plates
b. Area of the plates
c. Nature of the dielectric
d. Distance between the plates
Q22. Three-point starter can be used for:
a. Both shunt and compound motor
b. Series motor only
c. Both series and compound motor
d. Shunt motor only
Q23. Which of the following in NOT a trivalent impurity?
a. Gallium
b. Phosphorus
c. Boron
d. Indium
Q24. A transformer transfers which of the following parameters?
a. Voltage
b. Frequency
c. Current
d. Power
Q25. PIV in a full-wave rectifier is:
a. Vm/2
b. Vm/√2
c. 2Vm
d. Vm
Q26. In which type of amplifier does the output flow for the entire cycle of input signal ?
a. Class B
b. Class AB
c. Class C
d. Class A
Q27. Which of the following is a valid grade for which electric cables are commercially manufactured?
a. 230/400 V
b. 270/300 V
c. 50/100 V
d. 100/200 V
Q28. Which of the following material is NOT used as fuse wire?
a. Paper
b. Silver
c. Copper
d. Aluminium
Q29. In a DC shunt motor, the torque produced is proportional to:
a. Armature current
b. Ampere-turn
c. (armature current)²
d. (ampere-turn)²
Q30. Which of the following motor is self-starting?
a. Low horse power motor
b. Single-phase induction motor
c. Variable speed motor
d. Three-phase induction motor
Q31. In the _____region, a transistor acts as a closed switch.
a. Active region
b. Cut-off region
c. Inverse active region
d. Saturation
Q32. what is the surge resistance of cable?
a. 20 Ω
b. 5 Ω
c. 50 Ω
d. 10 Ω
Q33. In actual practice, the rating of transformer is specified in:
a. KA
b. KVA
c. KVAR
d. KW
Q34. A 3-point starter is used to:
a. Minimize back emf
b. Maximize armature current
c. Maximize back emf
d. Minimize armature current
Q35. The order in which the voltages in the phases reach their maximum positive value is called the_____.
a. Line voltage
b. Phase current
c. Phase voltage
d. Phase sequence
Q36. A feeder in transmission system feeds power to:
a. Distributors
b. Service main
c. Generating station
d. Generator and distributor
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Q37. Which of the following device is bidirectional?
a. GTO
b. TRIAC
c. SCR
d. BJT
Q38. Three resistance of 2 ohms, 3 ohms and 6 ohms are connected in parallel. The total resistance of the combination is:
a. 3 ohm
b. 36 ohm
c. 11 ohm
d. 1 ohm
Q39. For amplifier applications, a transistor needs to be biased to operate in which of the following regions?
a. Active region
b. Saturation region
c. Cut-off region
d. Depletion region
Q40. UJT is used for which of the following applications?
a. Attenuation
b. Amplification
c. Sawtooth waveform generation
d. Rectification
Q41. The ripple factor for a half-wave rectifier with capacitor is given by;
Q42. In a capacitor start single-phase motor, the motor will continue to run in the same direction if the capacitor is replaced by a:
a. Inductor
b. Resistor
c. Resistor and inductor
d. Resistor and capacitor
Q43. The loss that takes place due to winding resistance is called______.
a. Hysteresis loss
b. Eddy current loss
c. Copper loss
d. Iron loss
Q44. Among the following, which method is NOT preferred low resistances?
a. Potentiometer method
b. Ammeter-voltmeter method
c. Kelvin bridge method
d. Megohm bridge
Q45. In the case of direct current:
a. Magnitude of current remains constant
b. Magnitude and direction of current changes with time
c. Magnitude and direction of current remains constant
d. Magnitude of current changes with time
Q46. In a fleming’s right-hand rule, the thumb indicated the:
a. Direction of motion of conductor
b. Direction of current flow
c. Direction of induced voltage
d. Direction of magnetic field
Q47. In an induction motor, as the air gap increases:
a. Windage losses will increase
b. Speed of motor will decrease
c. Speed of motor will increase
d. Power factor will decrease
Q48. The expression for inductive reactance () of an AC circuit is:
a. 2πfL
b. 2πL
c. 2πf
d. 1/2πfL
Q49. In a balanced three-phase star connected system, if the line current is 30 A, then its phase current is:
a. 15 A
b. 30 A
c. 51.9 A
d. 17.3 A
Q50. In portable drills, which of the following motor is used?
a. Hysteresis motor
b. Repulsion motor
c. Capacitor run motor
d. Universal motor
Q51. The characteristics of pattern that appear on a CRT screen when sinusoidal voltages are simultaneously applied to horizontal and vertical plates are called______.
a. Phase patterns
b. Lissajous patterns
c. Eye patterns
d. Colour patterns
Q52. The input power of an electric heater that draws 10 A at 230 V supply source is:
a. 23 W
b. 2300 W
c. 230 W
d. 0 W
Q53. For transmission and distribution of electric power, which one of the following materials is NOT used?
a. Tungsten
b. Copper
c. Aluminium
d. Steel
Q54. In lap winding, the number of parallel paths are always:
a. Two
b. Same as the number of poles
c. Double the number of poles
d. Half the number of poles
Q55. Which one of the following materials is usually used for the construction of transformer core?
a. Copper
b. Aluminium
c. Silicon steel
d. Brass
Q56. Which of the following two losses are together called core loss?
a. Primary copper loss and secondary copper loss
b. Eddy current loss and hysteresis loss
c. Copper loss and hysteresis loss
d. Connector loss and transmission loss
Q57. overheating of DC motors is mainly due to:
a. Royal commutator
b. Overloads
c. absence of brushes
d. Loose parts
Q58. Conduit elbows are usually located at:
a. Sharp ends
b. The tapping of the connection
c. Straight runs
d. Away from walls
Q59. A DC generator works on the principles of:
a. Faraday’s law
b. Steinmetz’s law
c. Lenz’s law
d. Ampere’s law
Q60. In the _____region, a transistor acts as an open switch.
a. Saturation
b. Inverse active region
c. Active region
d. Cut-off region
Q61. Power transmission for long distance is carried out at:
a. High voltage
b. High current
c. Low current
d. Low voltage
Q62. For switching applications, a transistor needs to be biased to operate in which of the following regions?
a. Active region
b. Active or inverse active region
c. Inverse active region
d. Saturation or cut-off region
Q63. The most commonly used method for cooling power transformers is:
a. Natural air cooling
b. Oil cooling
c. Air blast cooling
d. Gas cooling
Q64. A three-phase power system with three voltages have an equal magnitude and are displaced at________from each other.
a. 100°
b. 120°
c. 90°
d. 180°
Q65. The ripple factor for a full-wave rectifier with capacitor is given by:
a. r = 1/ √3f RLC
b. r = 1/ 2√3f RLC
c. r = 1/ 4√3f RLC
d. r = 1/ 4√3f RL
Q66. Power consumed in a series RLC circuit can be calculated using:
a. P = IR
b. P = IR cos ф
c. P = VI
d. P = VI cos ф
Q67. Among the following, which feature is best suited for insulating materials?
a. High dielectric strength
b. Low mechanical strength
c. Low melting point
d. Good current conductivity
Q68. If a 4-pole induction motor has a speed of 1800rpm, then the frequency at which the motor is operating is:
a. 60Hz
b. 50Hz
c. 30Hz
d. 40Hz
Q69. Three identical resistors are first connected in a star and then in a delta configuration. The ratio of power consumption in the first combination to the second will be:
a. ⅓
b. 1/√3
c. 1
d. 3
Q70. Among the following, which material is a good conductor of electricity?
a. Silver
b. Glass
c. Bakelite
d. Rubber
Q71. The function of inverter in a UPS is to:
a. Convert DC to DC
b. Convert DC to AC
c. Convert AC to AC
d. Convert AC to DC
Q72. Conductance is defined as the reciprocal of:
a. Resistance
b. Capacitance
c. Inductance
d. Susceptance
Q73. For the maximum efficiency of a transformer:
a. Copper loss should be greater than iron loss
b. Copper loss should be zero
c. Copper loss should be less than iron loss
d. Copper loss should be equal to iron loss
Q74. Hysteresis loss can be minimized by selecting a material for the core that has:
a. Low hysteresis coefficient
b. High hysteresis coefficient
c. Unit hysteresis coefficient
d. Low transmission coefficient
Q75. copper loss is negligible at______.
a. ¼ load
b. Half load
c. No load
d. Full load