Sunday, 29 April 2018

Solved preview paper 3(101-145)


Q.101. One of the main application of Magneto-resistor
a.) Rectification
b.) Field compensation
c.) Voltage regulation✔
d.) Power amplification
Q.102. Input impedance of an ideal Op- Amp is
a.) Finite
b.) Zero
c.) Infinite✔
d.) Unity
Q.103. For the binary number 1110 1000 the equivalent hexadecimal number is
a.) F9
b.) F8
c.) E9
d.) E8✔
Q.104. In 2's complement from , -2  is
a.) 1011
b.) 1110✔
c.) 1100
d.) 1010
Q.105. The most commonly used logic family is
a.) ECL
b.) TTL
c.) CMOS✔
d.) PMOS
Q.106. ALE stand for
a.) Address latch enable✔
b.) Accumulator latch enter
c.) Address latch enter
d.) None of the above
Q.107. The number of gates in a SCR is
a.) 2✔
b.) 3
c.) 4
d.) 6
Q.108. Relaxation oscillator uses
a.) Tunnel diode
b.) UJT✔
c.) Both tunnel diode and UJT
d.) PIN
Q.109. In overhead lines we generally use
a.) Copper condenser
b.) ACSR conductor✔
c.) Aluminium conductor
d.) None of the above
Q.110. The electric power can be transmitted by
a.) Overhead system
b.) Underground system
c.) Either A or B✔
d.) None of the above
Q.111. Which variety of copper has the best conductivity
a.) Pure annealed copper✔
b.) Hard drawn copper
c.) Induction hardened copper
d.) Copper containing silicon
Q.112. Basic ceramic material is
a.) Limestone
b.) Clay✔
c.) Cellulose
d.) Sand
Q.113. Which of the following insulating material has the highest safe working temperature
a.) Polythene
b.) Bakelite
c.) Mica✔
d.) Empire cloth
Q.114. Thermocouple works on
a.) Thomson effect
b.) Seebeck effect✔
c.) Peltier effect
d.) Joule affect
Q.115. In a commutator
a.) Copper is harder than Mica✔
b.) Mica and copper are equally harder
c.) Mica is harder than copper
d.) None of the above
Q.116. An electric boiler draws 12 A  at 115 V for a period of 6 hours. If the electrical energy costs 30 paisa per kWh,  then cost of boiler operation in ₹ is
a.) 8.284
b.) 3.482
c.) 2.484✔
d.) 1.684
Q.117. A hundred watt 250 volt bulb is put in series with a 40 watt , 250 volt bulb across 500 volt supply. That total resistance offered by both the bulbs in the circuit in home is
a.) 218.75
b.) 318.75
c.) 3187.5
d.) 2187.5✔
Q.118. When a source is delivering maximum power to the load the efficiency will be
a.) Maximum
b.) Below 50%
c.) Above 50%
d.) 50%✔
Q.119. A 12 volt lead acid battery used in a car contains
a.) 10 cell connected in series
b.) 10 cell connected in parallel
c.) 6 cell connected in parallel
d.) 6 cell connected in series✔
Q.120. The force per metre length between two conductors 0.05 m apart carrying 1000 A and 5000 A is
a.) 20 N✔
b.) 5 N
c.) 50 N
d.) 25 N
Q.121. What will be the current passing through the ring shaped air cored cail when the number of turns is 800 and ampere-turn are 3200
a.) 0.25
b.) 2.5
c.) 4.0✔
d.) 0.4
Q.122. In RLC series circuit at resonance frequency the voltage across the resistance is
a.) Much lower than applied voltage
b) Equal to the applied voltage✔
c.) Much higher then applied voltage
d.)Function of the value of inductance
Q.123. An alternating voltage of (160+j120)V is applied to a circuit and the current in the circuit is given by (6+j8)A . The value of the circuit impedance in ohms is given by
a.)19.2-j5.6✔
b.)19.2+j5.6
c.)166+j128
d.)154-j112
Q.124. A resistor R in series with a capacitor C is connected to a 50 Hz , 240 volt supply. The register observe 300 watt 100 volt . The voltage across the capacitor is
a.) 118.17 V
b.) 318.17 V
c.) 218.17 V✔
d.) 418.17 V
Q.125. An alternating current is represented by i=70.7 sin 520t . Then the value of frequency is Hz is
a.) 73
b.) 93
c.) 53
d.) 83✔
Q.126. A battery of 50 cells in series is charged through a resistance of 4 ohm from a 230 volt supply. If the terminal voltage per cell is 2 volt and 2.7 volt respectively at the beginning and at the end of the charge. The charging current at the beginning is given by
a.) 22.5 A
b.) 12.5 A
c.) 32.5 A✔
d.) 18.5 A
Q.127. The power in the wind Pw through a given cross sectional area for a uniform wind velocity V is
a.) Pw=KV^3
b.) Pw=KV^2
c.) Pw=KV✔
d.) Pw=KV^4
Q.128. Which of the following statement is correct ?
a.) Arc in a circuit breaker is interrupted at Maximum current
b.) Arc in a circuit breaker is interrupted at maximum voltage
c.) Arc in a circuit breaker is interrupted at zero current✔
d.) Arc in a circuit breaker is interrupted at minimum voltage
Q.129. Which of the following circuit breaker has high reliability and minimum maintenance
a.) Oil circuit breaker
b.) Airblast circuit breaker
c.) Sf6 circuit breaker
d.) Vacuum circuit breaker✔
Q.130. The differential relaying system respond to
a.) Internal fault✔
b.) External fault
c.) Overvoltage fault
d.) Under current fault
Q.131. To protect the power transformer (Delta star)against internal faults the current transformer will have
a.) Delta - delta connections
b.) Delta - star connections
c.) Star - star connections
d.) Star - delta connections✔
Q.132. For a 400 kV line the spacing between phase conductors is around
a.) 8 m✔
b.) 11 m
c.) 14 m
d.) 17 m
Q.133. Bundled conductors are used to
a.) Reduce inductis of the line
b.) Reduce both inductance and capacitance
c.) Reduce Corona loss
d.) Reduce Corona loss and the line inductance✔
Q.134. The power factor of a system on a 460 volt 3 phase 60 Hz, in which the emitter indicate 10 volt and Watt metre reads 62 kW will be
a.) 0.95
b.) 0.78✔
c.) 0.85
d.) 0.72
Q.135. Which of the following protects the underground cables against mechanical injury
a.) Bedding
b.) Sheath
c.) Armouring✔
d.) None of these
Q.136. The thermal efficiency of a steam power station is
a.) 18%-20%
b.) 25%-30%✔
c.) 40%-50%
d.) 15%-20%
Q.137. Which of the following is not a secondary source of energy ?
a.) Solar power station✔
b.) Diesel power station
c.) Nuclear power station
d.) Thermal power station
Q.138. The synchronous speed of the revolving field depends upon
a) number of poles
b) supply frequency
c) flux
d) a and b are correct✔
Q.139. The frequency of induced emf in the rotor circuit is
a) maximum at stand still✔
b) zero at stand still
c) maximum at synchronous speed
d) none of these
Q.140. If one of the 3-phases of a 3-phase induction motor is disconnected while running at light load, it will
a) stop running
b) continue to run at same speed✔
c) run at low speed
d) run at high speed
Q.141. If the rotor terminals of a 3-phase slip ring induction motor are not short-circuited and the supply is given to the stator , the motor will
a) not start✔
b) start running
c) run at high speed
d) run at low speed
Q.142. Eddy current power loss in a magnetic material can be expressed as
a.)Pe=ke Bm^2t^2f^2 V watt✔
b.)Pe=ke Bm^2tf^2 V watt
c.)Pe=ke Bm t^2 f V watt
d.)Pe=ke Bm^2t^2f^2 V^2 watt
Q.143. In transistor with normal bias, the emitter Junction
a.) Has high resistance
b.) Reverse biased
c.) Has low resistance✔
d.) None
Q.144. Power factor of incandescent lamp is
a.) Zero
b.) Unity✔
c.) 0.8 legging
d ) 0.8 leading
Q.145. The colour of sodium vapour discharge lamp is
a.) Pink
b.) Red
c.) Bluish
d.) Yellow✔
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solved preview paper 3 (51-100)


Q.51. The phenomenon of squirrel cage motor some time showing a tendency to run at a very low speed is known as
a.) Cogging
b.) Crawling✔
c.) Damping
d.) Skewing
Q.52. A 5 H- HP 3 phase 400v star connected squirrel cage induction motor meant to drive a milling machine at starting takes about
a.) 40A✔
b.) 100A
c.) 150A
d.) 200A
Q.53. The starting torque of an induction motor can be increased by
a.) Increasing Rotor reactance
b.) Increasing the rotor resistance✔
c.) Increasing the supply frequency
d.) Giving supply through a star delta starter
Q.54. The span for full pitch coil wound for 6 poles is
a.) 180 degree mechanical
b.) 90 degree mechanical
c.) 60 degree mechanical✔
d.) 45 degree mechanical
Q.55. The armature flux opposes the main field flux when load power factor is
a.) Unity
b.) Zero lagging✔
c.) Zero leading
d.) 0.8 leading
Q.56. A commercial alternator has
a.) Rotating armature and stationary field
b.) Stationary armature and rotating field✔
c.) Both armature and field rotating
d.) Both armature and field stationary
Q.57. In alternator damper winding are used to
a.) Reduce Eddy current loss
b.) Prevent hunting✔
c.) Make the rotor dynamically balanced
d.) Reduce armature reaction
Q.58. The magnitude of the resultant magnetic field produced by a three phase current flowing through a three phase winding
a.) The maximum value of flux due to any one phase
b.) 1.5 time the maximum value of flux due to any one phase✔
c.) Half the value of maximum flux due to any one phase
d.) Twice tha maximum value of flux due to any one phase
Q.59. The pitch factor for 5/6 short pitch coil is
a.) 0.966✔
b.) 0.833
c.) 1.0
d.) 3.454
Q.60. Armature reaction in a electrical machine is the effect of
a.) Armature flux on the main field flux✔
b.) Heat produce on the armature winding
c.) Armature current on the output
d.) Armature flux on the output
Q.61. The speed regulation of synchronous motor is
a.) Unity
b.) Zero✔
c.) Infinity
d.) Always less then one
Q.62. The direction of the rotation of an ordinary shaded pole single phase induction motor
a.) Can be reversed by reversing the supply terminal connection to the stator winding
b.)can not be reversed✔
c.) Can be reversed by open circuiting the shading ring
d.) Can be reversed by short circuiting the shading ring
Q.63. In a single phase repulsion motor, torque is developed on the rotor when the brush axis is fixed
a.) At 90° electrical with the stator field axis
b.) In alignment with the stator field axis
c.) At an acute angle with the stator field axis✔
d.) At 90 degree mechanical with the stator field axis
Q.64 . A DC series motor when connected across an AC supply will
a.) Develop torque in the same direction✔
b.) Not develop any torque
c.) Draw dangerously high current
d.) Develop a pulsating torque
Q.67. The armature of a DC machine is made up of laminated sheets to
a.) Reduce hysteresis loss
b.) Reduce Eddy current loss✔
c.) Reduce armature copper loss
d.) Increase dissipation of heat from the armature surface
Q.68. The function of a brush and commutator arrangement in a DC motor
a.) To produce uni-directional torque✔
b.) To produce unidirectional current in armature
c.) To help in changing the direction of rotation of armature
d.) To reduce parking
Q.69. The armature winding of a DC machine is made up of a number of coils distributed in a large number of armature slots instead of placing all the coil in two slots to
a.) Gets sinusoidal EMF at the output terminals
b.) Have minimum heat dissipation from the armature✔
c.) Make the armature dynamically balanced
d.) Get the maximum generated EMF in the armature
Q.70. The maximum permissible operating temperature of class-E insulating material is
a.)130 degree
b.)120 degree✔
c.)180 degree
d.)105 degree
Q.71. The number of parallel paths in the armature winding of a four pole wave connected DC Machine having 22 coil-sides is
a.) 4
b.) 22
c.) 2✔
d.) 11
Q.71. The direction of rotation of a DC motor can be reversed
a.) By reversing the connection of both the armature and the field winding with the supply
b.) By reversing the connection of either the armature or the field✔ winding connection with the supply
c.) By reducing the field flux
d.) By introducing an extra resistance in the armature circuit
Q.72. To have sparkless commutation the armature reaction effect in a DC machine is neutralized by
a.) Using compensating winding and commutating poles✔
b.) Shifting the brush Axis from the geometrical neutral axis to the magnetic neutral axis
c.) Fixing the processes in alignment with the main pole axis
d.) Increasing the field excitation
Q.73. Which type of motor is preferred for traction work?
a.) DC series motor✔
b.) Three phase induction motor
c.) Universal motor
d.) Synchronous motor
Q.74. A solid angle is expressed in terms of
a.) Radians
b.) Degrees
c.) Radian/metre
d.) Steradian✔
Q.75. Glare is reduced by
a.) Increasing lamp height
b.) Using reflectors
c.) Using diffuser
d.) All of the above✔
Q.76. In induction heating which of the following is high
a.) Current✔
b.) Voltage
c.) Frequency
d.) Power
Q.77. The electrodes used for direct resistance heating are made of
a.) Mild steel✔
b.) Copper
c.) Carbon
d.) None of the above
Q.78. In which type of welding current is passed through the metal piece to be joint
a.) Arc
b.) TIG
c.) Resistance✔
d.) MIG
Q.79. In transmission line sag depends upon
a.) Conductor material
b.) Length of span
c.) The tension in conductor
d.) All of the above✔
Q.80. Electroplating is the process of
a.) Removing 1 metal from the other
b.) Coverings superior metal over the inferior metal✔
c.) Refining of metals
d.) All of the above
Q.81. Which of the following motor is used in household refrigerator?
a.) AC series motor
b.) DC shunt motor
c.) Reluctance motor
d.) Single phase induction motor✔
Q.82. Voltage regulator are used to _________the voltage
a.) Increase
b.) Stabilize✔
c.) Decrease
d.) None of the above
Q.83. The direct current system employed for tramways operates on
a.) 3000 V
b.) 1500 V
c.) 750 V✔
d.) 440 V
Q.84. Low frequency operation of overhead line in traction system
a.) Reduce the spacing between substation
b.) Increase the spacing between substation✔
c.) All of the above
d.) None of the above
Q.85. In electrolytic process the electrical energy is converted into
a.) Mechanical energy
b.) Heat energy
c.) Chemical energy✔
d.) None of the above
Q.86. Ajax Wyatt furnace is started when
a.) Field below core level
b.) Fully filled
c.) Field above core level✔
d.) All of the above
Q.87. The output of full wave rectifier contains
a.) Only even harmonics
b.) Only odd harmonics✔
c.) Both odd and even harmonics
d.) No harmonics
Q.88. Which of the following has negative temperature co-efficient
a.) Electrolyte✔
b.) Brass
c.) Silver
d.) Mercury
Q.89. A wire of resistance R has its length and area of cross section doubled heat resistance becomes
a.) R✔
b.) R/4
c.) 2R
d.) 4R
Q.90. The unit of retentivity is
a.) Ampere return
b.) Weber
c.) Ampere turn/metre
d.) Weber/metersquare✔
Q.91. Which material has least specific resistance
a.) Mercury✔
b.) Zinc
c.) Copper
d.) Lead
Q.92. In an a.c. circuit M.I. metres measure
a.) Mean value
b.) Peak value
c.) R.M.S. value✔
d.) Average value
Q.93. Economisers are used to heat
a.) Air
b.) Steam
c.) Feedwater✔
d.) None
Q.94. A coil has 1000 turns and current of 8 ampere causes a flux of 5 milli-weber to it .The inductance of coil will be
a.) 1.0 H
b.) 2.15 H
c.) 1.5 H✔
d.) 2.0 H
Q.95. Internal resistance of dry cell is
a.) 1-15 ohm
b.) 2-5 ohm
c.) 1-1.5 ohm
d.) 0.2-0.4 ohm✔
Q.96. Bronze is an alloy of
a.) Copper and Zinc
b.) Copper zinc and Tin
c.) Copper and Tin✔
d.) None
Q.97. Suitable turbine used for harnessing tidal power is
a.) Francis turbine
b.) Pelton wheel
c.) Kaplan turbine✔
d.) None
Q.98. Advantage of hydropower over Thermal Power is
a.) Low initial cost
b.) Low operatinng cost✔
c.) Continuous power
d.) None
Q.99. Impedance relay can be used for
a.) Earth fault
b.) Phase fault only
c.) Both Earth and phase fault✔
d.) None
Q.100. For energy efficient Motors which of the following is correct
a.) Use more power
b.) Used low quality material
c.) High reliability✔
d.) Less cost
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Solved preview paper 3 (1to50)


Q.1. Pelton wheel is which type of turbine?
a.) Reaction turbine
b.) Impulse turbine✔
c.) Both A and B
d.) None of these
Q.2. Hey generating station has a maximum demand of 35,500 kW and has connected load of 6500 kW. The number of units generates are annually 25.6 into 10^7 the demand factor is
a.)0.646
b.)0.746
c.)0.546✔
d.)0.436
Q.3. The principle of dynamically induced EMF is utilised in:
a.) Transformer
b.) Choke
c.) Generator✔
d.)Thermocouple
Q.4. Which of the following is not a part of the dc machine
a.) Armature
b.) Commutator
c.) Field winding
d.) Damping winding✔
Q.5. 8 Ball Pool generator with 16 coils has a two layer lap winding the pole pitch is
a.)32
b.)16
c.)8✔
d.)4
Q.6. The current drawn by a 120 V DC motor with back EMF of 110 V and armature resistance of 0.04 ohms is
a.)5A
b.)25A✔
c.)275A
d.)300A
Q.7. The output indicate on the name plate of any motor is always the
a.) Gross power
b.) Power drawn in KVA
c.) Power drawn in KW
d.) Output power at the shaft✔
Q.8. When voltage in transformer from primary to secondary then it is______.
a.) Multiplied by k^2
b.) Multiplied by K✔
c.) Divided by K^2
d.) Divided by K
Q.9. A 50 Hz operation a single phase transformer has hysteresis loss 200W and Eddy current loss of 100W its core loss at 60 Hz frequency operation will be
a.)432W
b.)408W
c.)384W✔
d.)360W
Q.10. A three phase induction motor with rotor circuit open will
a.) Not run✔
b.) Run normally
c.) Get overheated
d.) Make  noise
Q.11. A 3 Phase 6 pole 50 Hz induction motor is running at 5% slip what is the speed of the motor
a.)850 rpm
b.)900 rpm
c.)950 rpm✔
d.)1000 rpm
Q.12. The starting torque of an induction motor varies as:
a.) f
b)1/f^2✔
c.)1/f
d.)f^2
Q.13. The two bright and one dark lamp method is used for
a.) Determination of phase sequence
b.) Synchronising of 3 phase alternator✔
c.) Synchronising of single phase alternator
d.) Transfer of load
Q.14. Capacitor start capacitor run motor are used in
a.) Hlists
b.) Rolling Mills✔
c.) Mining
d.) Refrigerator
Q.15. Which part of transformer is subjected to maximum heating?
a.) Frame
b.) Core
c.) Winding✔
d.) Oil
Q.16. Open circuit test in a transformer is performed with
a.) Rating Transformer voltage✔
b.) Rated Transformer current
c.) Direct current
d.) High frequency supply
Q.17. The current from the stator of an alternator is taken out to the external load circuit through
a.) Slip ring
b.) Commutator segment
c.) Solid connection✔
d.) Carbon brushes
Q.18. In rotor resistance control methods______with the increase in speed
a.) Torque increase
b.) Torque decreases✔
c.) Slip increased
d.) Losses increase
Q.19. The stator winding of a single phase induction motor is split it into two parts in order to
a.) Improve efficiency
b.) Improve power factor
c.) Develop starting torque✔
d.) Increase speed
Q.20. The cheapest system of in interval wiring is ______wiring
a.)Cleat✔
b.)Casing capping
c.)CTS or TRS
d.)Conduit
Q.21. The rating of fuse wire is always expressed in
a.)Volts
b.)Amperes✔
c.)Ampere-volt
d.) Ampere hour
Q.22. The earth potential is taken as
a.) Zero✔
b.) That of supply
c.) Infinite
d.) None of these
Q.23. Which of the following will be served as a Donor impurity in Silicon ?
a.) Boron
b.) Indium
c.) Germanium
d.) Antimony✔
Q.24. Without a DC source a clipper act like as
a.) Clamper
b.) Chopper
c.) Rectifier
d.) Demodulator✔
Q.25. For germanium P-N junction the maximum value of barrier potential is
a.) 0.3 V
b.) 0.7 V✔
c.) 1.3 V
d.) 1.7 V
Q.26. 2'S complement of the number of 1010101 is
a.) 01010 10
b.) 01010 11✔
c.) 1 10 10 10
d.) 11100 11
Q.27. An XOR  gate produces output only when two inputs are
a.) High
b.) Low
c.) Different✔
d.) Equal
Q.28. The number of flip-flop required in a decade counter
a.) 2
b.) 3
c.) 4✔
d.) 10
Q.29. A 1 mA ammeter has a resistance as 100Ω.  It is to be converted to a 1 A ammeter. The value of shunt resistance is
a.) 0.001 Ω✔
b.) 0.1001 Ω
c.) 100001 Ω
d.) 100 Ω
Q.30. The difference between the indicating value and the true value of a quantity is
a.) Gross error
b.) Absolute error✔
c.) Dynamic error
d.) Relative error
Q.31. Which one of the following metres in a integrating type instruments
a.) Ammeter
b.) Voltmeter
c.) Wattmeter
d.) Energymeter✔
Q.32. A Thermocouple Ammeter give full scale deflection at 10A .  When the ammeter read one fifth of the scale the current will be
a.) 2A
b.) 4A
c.) 4.47A✔
d.) 5.78
Q.33. Which bridge is used to determine frequency
a.) Anderson bridge
b.) De-sauty bridge
c.) Wein bridge✔
d.) Campbell bridge
Q.34. A digital voltmeter has a read out range from 0 to 9999 . When full scale reading is 9.999 V , the resolution of the full scale reading is
a.) 0.001
b) 1000
c.) 3 digit
d.) 1mV✔
Q35. In a rotating electrical machine , the insulation temperature limit for class B type is
a.)105°
b.)130°✔
c.)150°
d.)180°
Q.36. For Arc heating the electrode used are made up of :
a.) Copper
b.) Graphite✔
c.) Tungsten
d.) Aluminium
Q.37. In electric welding major personal hazards are
a.) Welding spatter
b.) Flying Sparks
c.) Harmful infrared and ultraviolet rays from arc✔
d.) All of the above
Q.38. Which of the following need the highest level of illumination
a.) Living room
b.) Kitchen✔
c.) Proof reading
d.) Hospital wards
Q.39. Long distance Railway operated on
a.) 600V dc
b.) 25 kV single phase ac✔
c.) 25 kV 3 phase ac
d.) 15 kV 3 phase ac
Q.40.The speed time curve for urban service has no
a.) Coasting time
b.) Free running period✔
c.) Breaking period
d.) Acceleration period
Q.41. Total flux required in any lighting scheme depends inversely on
a.) Surface area
b.) Illumination
c.) Coefficient of utilisation
d.) Space height ratio✔
Q.42. The least expensive drive is
a.) Belt drive✔
b.) Rope drive
c.) Chain drive
d.) Gear drive
Q.43. The ratio of the primary to secondary voltage of a transformer is 2:1 . The savings in terms of weight of copper required if an auto transformer is used instead of two winding Transformer
a.) 50%✔
b.) 33.33%
c.) 66.66%
d.) 97%
Q.44 cooling of transformer is necessary to
a.) Increase the efficiency
b.) Dissipate the heat generated in the winding✔
c.) Reduce the losses
d.) Reduce humming
Q.45. The all day efficiency of transformer is the ratio of
a.) kWh output and kWh input per day
b.) kWh output and input in a day✔
c.) Output power and input power
d.) Input power and output power
Q.46. For satisfactory parallel operation of two single phase Transformers a number  of conditions are to be fulfilled. A number of conditions are written below. Indicate which of these is not required to be fulfilled
a.) KVA rating of the two Transformers should be equal✔
b.) Transformers should be properly connected with regard to their polarity
c.) Voltage rating of the primary winding should be suitable for supply system voltage and frequency. The turn ratio of the transformer should be equal
d.) The percentage impedance of the 2 Transformer should be equal
Q.47. A 400 V 50 Hz 3 phase induction motor rotate at 1440 RPM on full load. The motor is wound for
a.) 2-poles
b.) 4-poles✔
c.) 6-poles
d.) 8-poles
Q.48. The relation between synchronous speed,  stator  supply frequency and stator number of poles of a three phase induction motor is given by
a.)Ns=P/120f
b.)f=120Ns/P
c.)f=P.Ns/120✔
d.)Ns=120P/f
Q.49. Torque developed by a three phase,  400 V induction motor is 100 N-m . If the supply voltage is reduced to 200 V that developed will be
a.) 50 N-m
b.) 25 N-m✔
c.) 200 N-m
d.) 62.5 N-m
Q.50. For a three phase induction motor having rotor circuit resistance of 6 ohm,  maximum torque occur at a slip of 0.6.  The value of stand still rotor circuit reactance is
a.) 4.44 ohm
b.) 0.36 ohm
c.) 1 ohm
d.) 10 ohm✔
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Thursday, 26 April 2018

Solved questions preview paper (2) 101-150


Q.101. The phase different between current 
and voltage is 90° , the real power will be
a.)Minimum
b.)Maximum
c.)Zero✔
d.)Cannot be determined
Q.102. Capacitor bank are connected with ac induction motor
a.)In parallel✔
b.)In series
c.)Not connected at all
d.)Can be connected either way series/parallel
Q.103.At resosnance
a.) Magnitude of capacitive reactance > magnitude of inductive reactance
b.)Magnitude of capacitive reactance =magnitude of inductive reactance✔
c.)Magnitude of capacitive reactance <magnitude of inductive reactance
d.)None of the above
Q.104. An RLC circuit has a resonance frequency of 160kHz and a Q-factor of 100, its bandwidth is
a.)1.6kHz✔
b.)0.625kHz
c.)16MHz
d.)None of these
Q.105. A 230 V, 100 W bulb is connected in series with a room heater . If now this bulb is replaced by a 230V , 40W bulb, the heater output will
a.)Decrease✔
b.)Increase
c.)Remain the same
d.)Unjustified
Q.106. A certain AC circuit has resistance of 100 ohm and impedance of 200 ohm the phase angle of voltage and current of the circuit is
a.)60°✔
b.)30°
c.)90°
d.)45°
Q.107. The time constant of an inductive circuit is one second if its inductance page 8 H, the resistance of the coil will be
a.)8ohm✔
b.)1/8ohm
c.)0.25ohm
d.)1ohm
Q.108.______can not sustain much voltage fluctuation
a.)Sodium vapour lamp
b.)Mercury vapour lamp
c.)Incandescent lamp✔
d.)Fluorescent lamp
Q.109. Clamping circuit are one which insert
a.) AC component in signal
b.) DC component in signal✔
c.) Both AC and DC
d.) None of these
Q.110. To a highly inductive circuit a small capacitance is added in series the phase angle between voltage and current will
a.)Decrease✔
b.)Increase
c.)Remain same
d.)Indeterminate
Q.111. Whenever current is supplied by a source its terminal voltage
a.)Increase
b.)Decrease
c.)Remain constant
d.) Increase exponentially
Q.112. Which of the following cannot be connected in series unless they are identical
a.)Voltage source
b.)Current source✔
c.)Both of above
d.)Resistance
Q.113. Series circuit consist of R 20 ohms, and L 20mH  and AC supply 60 volt with frequency 100 Hz the current in R is
a.)2.54 A✔
b.)1.27A
c.)5.08A
d.)10.16A
Q.114.If the resistor an inductor are connected in series across a voltage source. Which in two parameters in that circuit increases if frequency of voltage source increases?
a.)VL and Z ✔
b.)Z and I
c.)VL and I
d.)VL and VR
Q.115.The maximum number of  wattmeter (s) required to measure 3phase 3wire balanced or unbalanced power in delta connected load
a.) 0
b.) 2✔
c.) 3
d.) 6
Q.116. When ac supply given to the transformer , the flux will depend upon
a.)Current
b.)Voltage
c.)Frequency
d.)Both voltage and frequency✔
Q.117. The stationary alternator must not be connected to live bus bar because it will result in
a.)Short circut✔
b.)Open circuit
c.)Nothing will happen
d.)Floating
Q.118. Which one of the following statement is correct, for connecting a alternator to infinite bus?
a.)Phase sequence should be same✔
b.)Frequency need not be same
c.)Terminal.voltage of alternator need not be same with existing bus
d.) None of the above
Q.119. An alternator having induced
emf of 1.6 Pu connected to an infinite bus of 1.0 Pu, if the bus has reactance of 0.6 Pu and alternator has reactance of 0.2Pu . The maximum power that can be transferred is given  by.
a.)1Pu
b.)2Pu✔
c.)3Pu
d.)5Pu
Q.120.A 50Hz 4pole turbo generator rated at 20MVA 13.2kV has inertia constant H=3kW-sec/kVA. The kinetic energy stores in rotor
a.)80MJ
b.)60MJ✔
c.)20MJ
d.)10MJ
Q.121. In a series resonant circuit impedance is
a.) Minimum✔
b.) Maximum
c.) Zero
d.) None of these
Q.122. Class B amplifier is baised
a.) At mid point of load line
b.) Just at cutoff✔
v.) Nearly twice cut off
c.) None of the above
Q.123. For making a capacitor it is better to selected A dielectric having
a.) Low permittivity
b.) High permittivity✔
c.) Permittivity same as that of air
d.) Permittivity more than that of air
Q.124. Plug setting of a relay can be altered by varying
a.) Air gap of magnetic path
b.) No. of ampere turn✔
c.) Adjusttable back up stop
d.) None of these
Q.125. Class B insulator can be a temperature up to
a.)130✔
b.)120
c.)105
d.)90
Q.126. If the fault current is 2000 ampere the real setting is 50% and CT ratio is 400 : 5 then plug setting multiplier will be
a.)10A✔
b.)15A
b.)25A
c.)50A
Q.127. Sulphation in a lead acid battery occur due to
a.) Heavy charging
b.) Fast charging
c.) Trickle charging
d.) Incomplete charging✔
Q.128. An ideal voltage source should have
a.) Large value of EMF
b.) Small value of EMF
c.) Zero source resistance✔
d.) Infinite source resistance
Q.129. A coil of negligible resistance as an induction of 100 mH. tThe current passing through the coil changes from 2 ampere to 4 ampere at a uniform rate in 0.1 second the voltage across the coil during this time would be____V
a.)2✔
b.)8
c.)36
d.)50
Q.130. What is represented by the hypotenus of Impedance Triangle
a.) Apparent power
b.) Resistance drop
c.) Reactive drop
d.) Impedance drop✔
Q.131.A 60 watt bulb in series with a room heater is connected across the mains. If the 60 watt bulb is replaced by 100W bulb
a.)The heater output will increase✔
b.)The heater output will decreas
c.)The heater output will be same
d.)The heater output will slightly decrease
Q.132. A cube of material of side 1cm has a resistance of 0.02Ω between its opposite faces. If the same volume of the material has a length of 4cm and a uniform cross section , the resistance of this length will be
a.)0.128Ω
b.)0.064Ω
c.)0.032Ω✔
d.)0.016Ω
Q.133. Which one of the following is not a condition of parallel operation of transformer
a.)MVA rating of transformer must be same ✔
b.)Voltage ration of transformer must be same
c.)Percentage impedance  of transformer should be same
d.)Polarity of transformer must be identical
Q.134. If the supply frequency of a transformer increases the output voltage of the transformer will
a.) Decrease
b.) Increase proportionally✔
c.) Remain same
d.) Increase very rapidly
Q.135.In a core type transformer
a.) HV winding is placed nearer to the core limb
b.) LV winding is placed nearer to the core limb✔
c.) Any of the LV or HV can be placed nearer to the core limb
d.) HV and LV windings are placed in different Cor limb
Q.136. The primary secondary winding of a transformer are
a.) Conductivity linked
b.) Inductively linked✔
c.) Electrically linked
d.) MechanicallyLinked
Q.137. At what Power factor in the voltage regulation of a transformer can be zero
a.) Leading power factor✔
b.) Lagging power factor
c.) Unity power factor
d.) Zero power factor
Q.138. In a three phase Star delta transformer what is the angle between primary and secondary phase voltage
a.) Delta side legs by 30°
b.) Star side legs by 30°
c.) Star side leads by 30°
d.) Delta side leads by 30°✔
Q.139. What will be the Eddy current loss if the supply frequency of a transformer become double
a.) 8 times
b.) Remain same
c.) Doubled
d.) 4 time✔
Q.140. The efficiency of a transformer is mainly depend upon
a.) Core losses✔
b.) Copper losses
c.) Stray losses
d.) Dielectric losses
Q.141. If supply frequency of a transformer decreases
a.) Both Eddy current and hysteresis losses will increase
b.) Eddy current loss will increase but hystresis loss will decrease
c.) Both Eddy current hysteresis losses will decrease✔
d.) Eddy current loss will decrease but hysteresis loss will increase
Q.142. Transformers operating in parallel will share the load depending upon their
a.) Leakage reactance
b.) Rating✔
c.) Efficiency
d.) Percentage impedance
Q.143. No load primary current in a transformer
a.) Leg behind applied voltage somewhat less than 90°✔
b.) Lags behind applied voltage by exactly 90°
c.) Lead the applied voltage by exactly 90°
d.) Leads the applied voltage somewhat less than 90°
Q.144. Which of the following is minimised by laminating the core of a transformer
a.) Hysteresis loss
b.) Eddy current loss✔
c.) Copper loss
d.) Stray loss
Q.145. Breather is provided in a Transformer to
a.) Absorb moisture from air entering in Transformer as well as provide breathing to the Transformer✔
b.) Provide cold air in transformer
c.) Absorb moisture from air entering in Transformers
d.) Filter the Transformer oil
Q.146. Iron loss in transformer mainly occur in
a.) Iron made tank of transformer
b.) Steel core in transformer✔
c.) Winding of transformer
d.) Transformer insulating oil
Q.147. Which of the following losses in the Transformer varies with load
a.) Copper loss✔
b.) Eddy current loss
c.) Hysteresis loss
d.)Stray loss
Q.148. In a transformer the magnetic coupling between the primary and secondary winding can be increased by
a.) Increasing the number of turns
b.) Using soft material for winding
c.) Using the magnetic core of low reluctance✔
d.) Using Transformer oil of better quality
Q.149. The short circuit test on transformer is conducted to obtain
a.) Copper losses✔
b.) Core losses only
c.) Eddy current loss
d.) Hysteresis loss
Q.150. In a transformer short circuit test and open circuit test are conducted
a.)In LV side of transformer
b.)In HV side and LV side of transformer respectively ✔
c.)In LV side and HV side of transformer respectively
d.)In HV side of transformer
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Solved questions preview paper (2) 51-100


Q.51. The magnitude of induced EMF in a coil is directly proportional to the rate of change of flux linkage. This is known as
a.) Joule's law
b.) Faraday's second law of electromagnetic induction✔
c.) Faraday's first law of electromagnetic induction
d.) Coulomb's Law
Q.52. The magnetic potential in a magnetic circuit can be measured in term of
a.)mmf✔
b.)emf
c.)Farad
d.)Coulomb
Q.53. The point in a magnet where the intensity of magnetic lines of force is maximum
a.) Magnetic pole✔
b.) South Pole
c.) North Pole
d.) Unit pole
Q.54 which of the following magnetic materials can be easily magnetized in both direction
a.) Soft magnetic materials✔
b.) Hard magnetic material
c.) High hysteresis lost materials
d.) No hysteresis loss materials
Q.55 the current of electric circuit is analogous to which quantity of a magnetic circuit
a.) MMF
b.) Flux✔
c.) Flux density
d.) Reluctivity
Q.56. The ability of material to conduct magnetic flux through it
a.) Permittivity
b.) Reluctivity
c.) Conductivity
d.) Permeability✔
Q.57 small voltage generated by a conductor with current in an external magnetic field
a.) Skin effect
b.) Magnetic effect
c.) Hall effect ✔
d.) Flywheel effect
Q.58 A length of wire has a resistance of 10 ohms what is the resistance of a wire of the same material three times as long and twice the cross-sectional area
a.)30ohms
b.)20ohms
c.)15ohms✔
d.)7ohms
Q.59. The ratio of w W/VA in an AC circuit means
a.) Power factor✔
b.) Reactive power
c.) Quality factor
d.) Load factor
Q.60.Kirchhoff's laws (KCL and KVL) are applicable to
a.) DC circuit
b.) AC circuit
c.) DC as well as AC circuit✔
d.) Passive networks alone
Q.61. What is considered as the most important Value of A sine wave
a.) Effective value✔
b.) Peak value
c.) Average value
d.) Instantaneous value
Q.62. The voltage leg the current by pi/2. cycle in a
a.) Purely resistive circuit
b.) Purely inductive circuit
c.) Purely capacitive circuit✔
d.) Circuit containing resistance capacitance and inductance
Q.63 For a series circuit the higher the quality factor
a.) The greater the bandwidth
b.) The narrow the pass band✔
c.) The broader the business curve
d.) The wider the pass band
Q.64 voltage resonance means
a.) Series resonance✔
b.) Parallel resonance
c.) Current magnification
d.) Gain magnification
Q.65 which component oppose voltage change
a.) Resistor
b.) Inductor
c.) Capacitor✔
d.) Transistor
Q.66 a transistor configuration with the lowest current gain
a.) Common base✔
b.) Common emitter
c.) Common collector
d.)Emitter follower
Q.67 there are two mechanism by which holes and electrons move through a silicon crystal they are
a.) Covalent bond and recombination
b.) Diffusion and drift✔
c.) Free and charged particles
d.) Forward and reverse bias
Q.68 the peak inverse voltage of a full wave Centre tapped rectifier circuit is equal to ________of the input signal
a.) Thrice the peak
b.) Twice the peak✔
c.) One-half
d.) One third
Q.69. Which of the following has the least noise level
a.)FET✔
b.)BJT
c.)Triode
d.Tetrode
Q.70. Asynchronous motor always run at synchronous speed because
a.) Of the action ofamorstisseur  winding
b.) The lenz's law can not be violated
c.) Of magnetic locking between the stator and Rotor✔
d.) None of these
Q.71. The rotor of three phase induction motor always runs at
a.) Synchronous speed
b.) Less than synchronous speed✔
c.) More than synchronous speed
d.) None of these
Q.72. If one of the three phase of a three phase induction motor is disconnected while running at light load it will
a.) Stop running
b.) Continue to run at same speed✔
c.) Run at low speed
d.) Run at high speed
Q.73. If a three phase induction motor runs on 2 phase supply it will
a.) Run at low speed
b.) Run with jerks
c.) Likely to burn✔
d.) Blow off the fuses
Q.74.Majority of the induction motor have
a.) Totally enclosed frame
b.) Totally enclosed when closed frame✔
c.) Drip proof type frame
d.) None of these
Q.75.Which motor  is widely used
a.) Squirrel cage induction motor✔
b.) Slip ring induction motor
c.) Wound rotor synchronous motor
d.) Salient pole  synchronous motor
Q.76 The scale of moving iron instrument is
a.) Uniform
b.)Cramped✔
c.) First uniform then conjested
d. None of these
Q.77. For increasing the range of voltmeter connect a
a.) High value resistance in series with voltmeter✔
b.) Low value resistance in series with voltmeter
c.) High value resistance in parallel with voltmeter
d.) Low value business in parallel with voltmeter
Q.78. The most commonly used type of single phase energy metre is
a.) Dynamometer
b.) Electrostatic type
c.) Induction type✔
d.) Moving coil type
Q.79. In steam power plant water is used for pulling purpose in
a.) Condenser✔
b.) Turbine only
c.) Boiler tubes
d.) Both B and C
Q.80. A Kaplan turbine is
a.) Inward flow impulse turbine
b.) Outward flow reaction turbine
c.) A high head mixed flow turbine
d.) Low head axial flow turbine✔
Q.81. Nuclear reactor generally employs
a.) Fusion
b.) Fission✔
c.) Both A and B
d.) None of these
Q.82 In a fuel cell electricity is produced by
a.) Combustion of fuel in absence of oxygen
b.) Oxidation of fuel✔
c.) Thermionic
d.) None of these
Q.83. The corona effect can be minimised by increasing
a.) The length of the conductor
b.) Spacing between the conductors
c.) Diameter of the conductors
d.) Both spacing between conductors and diameter of the conductors✔
Q.84. Power can be transferred only If reactance is
a.) Absent
b.)Present✔
c.)Zero
d.)None  of these
Q.85. In a three phase system the phasor form of phase current is zero. It means absence of
a.) Positive sequence component
b.) Negative sequence component
c.) Zero sequence component✔
d.) All of these
Q.86 switching protection are undertaken by.
a.) Switchgear✔
b.) Lightning arrester
c.) Fuse
d.) Relays
Q.87.Switching surge
a.)High voltage DC
b.)High voltage AC
c.)Short duration transient voltage✔
d.)Low impedance voltage
Q.88. The impurity in a liquid dielectric, which has significant effect in reducing the breakdown strength is
a.)Dust✔
b.)Dissolved
c.)Moisture
d.)None of these
Q.89.In what are long ,EHV transmission lines in interconnected power system generally protected
a.)Over current protection
b.)Pilot protection✔
c.)Distance protection
d.)Differential protection.
Q.90. The most economic load on an overhead line is
a.) Less than the natural load
b.) Equal to the natural load
c.) Greater than the natural load✔
d.) None of these
Q.91. The characteristics of drive for crane hosting is
a.) Smooth movement
b.) Precise control
c.) Fast speed control
d.) All of these✔
Q.92. Non metallic conduit wiring generally made of
a.) Rubber
b.) Cork
c.) Wood
d.) PVC✔
Q.93.Inside the earth or pit, the earthing electrode should be placed
a.)Vertical✔
b.)Horizontal
c.)Inclined at 45°
d.)Inclined at any angle other then45°
Q.94.In three phase half wave rectifier, each diode conducts for a duration of
a.)180°
b.)30°
c.)60°✔
d.)45°
Q.95. During forward blocking state , a thyristor is associate with
a.)Large current ,low voltage
b.)Low current ,large voltage✔
c.)Medium current, large voltage
d.)None of these
Q.96.The liberation of electrons from the surface of a substance is called
a.)Bombardment of electron
b.)Electronic emission✔
c.)Movement of free electrons
d.)Ion emission
Q.97.The work function of metal is generally expressed in
a.)Joules
b.)Volts
c.)Electrons
d.)Electron volts✔
Q.98.Then 2's complement of the number 0111 is
a.)11001✔
b.)11000
c.)00011
d.)11111
Q.99. What is the base of hexadecimal number system?
a.)10
b.)8
c.)16✔
d.)9
Q.100. One  cloulomb is equal to
a.)6×10^12 electrons
b.)6×10^10 electrons
c.)6×10^15 electrons
d.)6×10^18 electrons✔
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Solved Question preview paper (2) 1-50

Q.1. By looking at which part of the motor it can be easily confirmed that a particular motor is DC motor
a.)Frame
b.) Shaft
c.) Commutator✔
d.) Stator
Q.2. In regenerative braking which of the following is true
a.) Motor energy is dissipated as heat
b.) Motor energy is dissipated in armature heating
c.) Motor energy is dissipated in voltage loss
d.) Motor is mode to run as generator✔
Q.3. Which of the following load normally needs starting torque more than rated torque
a.) Blower
b.) Conveyors✔
c.) Air compressor
d.) Centrifugal pump
Q.4. Which of the following is not a vector quantity
a.) Linear momentum
b.) Angular momentum
c.) Electric field
d.) Electric potential✔
Q.5. Magnetic moment is a
a.) Pole strength
b.) Universal constant
c.) Scalar quantity
d.) Vector quantity✔
Q.6. Auto transformer makes affecting savings on Copper and copper losses when its Transformer ratio is equal to
a.) Approximate one✔
b.) Less than 1
c.) Greater than 1
d.) None of the above
Q.7. In circle diagram of induction motor diameter of circle represents which of the following
a.) Slip
b.) Rotor current✔
c.) Running torque
d.) Line voltage
Q.8. Inside a hollow conducting sphere
a.) Electric field is zero✔
b.) Electric field is a non zero constant
c.) Electric field changes with magnitude of the charge given to the conductor
d.) Electric field changes with distance from the centre of sphere
Q.9. To infinite parallel metal plates are charged with equal surface charge density of the same polarity. The electric field in the gap between the plate is
a.) Same as the product by 1 plate
b.) Double the field produced by 1 plate
c.) Depend on coordinates of field plate
d.) Zero✔
Q.10. The chemical effect of current is used in
a.) DC ampere hour meter✔
b.) DC ammeter
c.) DC energy meter
d.) None of the above
Q.11. Permittivity of free spare is equal to
a.) 8.854×10 - 8 F/m
b.) 8. 84× 10-12F/m✔
c.) 9×10-9 F/m
d.) 6×10 -12F/m
Q.12. Swamping resistance is used to compensate
a.) Error due to temperature variation✔
b.) Compensate error due to strong magnetic field
c.) Both A and B
d.) None of these
Q.13. 25kV, 50Hz 1phase supply is used for supplying power to the locomotives throughout India except which zone ?
a.) West✔
b.) East
c.)South
d.) North East
Q.14. Unit of deflection sensitivity of a CRO is
a.) V /mm
b.) Meter/ volt✔
c.) mm per mV
d.) mm /v
Q.15. ALNICO  is an alloy of
a.) Iron ,aluminium
b.) Aluminium ,Nickel
c.) Iron ,Cobalt, Nickel✔
d.) Aluminium ,nickel, iron and Cobalt
Q.16. Three resistors each of R ohms connected to form a triangle. the resistance between any two terminals will be
a.)3/2R
b.)2/3R✔
c.)P/2
d.)3R
Q.17. Air core Transformer as compared to iron core Transformer has
a.) More copper loss
b.) Less magnetic core loss
c.) More magnetic core loss
d. No magnetic core loss✔
Q.18. choose the best suitable of diamagnetic :paramagnetic material
a.) water :air✔
b.) Iron : steel
c.) Permalloy : super alloys
d.) Nickel : Cobalt
Q.19 find the odd one out
a.) Absorptivity
b.) Emissivity
c.) Refractive index
d.) Dielectric strength✔
Q.20. Grounded wire is used to
a.) To give sport to Towers
b.) Give a good regulations
c.) Increase conductivity of wire
d.) Connect a circuit conductor to an Earth plate✔
Q.21. Which of the following has approx zero temperature coefficient of resistance
a.)Manganin✔
b.) Carbon
c.) Porcelain
d.) copper
Q.22. Siemens are unit of
a.) Resistance
b.) conductance✔
c.) Capacitance
d.) Impedance
Q.23. If 220 volt heater is used on 110 volt supply heat produced will be
a.) Half Times
b.) 2 times
c.) One fourth✔
d.) 4 times
Q.24. If 5 resistance of 50 ohms are connected in parallel then unitor resistance will be
a.)1Ω
b.)10Ω✔
c.)100Ω
d.)250Ω
Q.25. If four resistance of 50 ohms each are connected in series across 250 volts supply and 1 resistance become open circuit then voltage across that register will be
a.) 0
b.)infinite✔
c.)250volts
d.)Any value
Q.26. In a three phase balanced load the power consumed is given by
a.)3VLILcosΦ
b.)√3VL IL cosΦ✔
c.)√3Vph Iph cosΦ
d.)VL IL cosΦ
Q.27. When two wattmeter are used to measure Pawar of three phase balanced circuit and one wattmeter reads negative ,it means power factor of load is
a.) Zero
b.) More the 0.5
c.)Less then 0.5
d.) 1✔
Q.28. 3 identical resistors each of 15 ohm are connected in Star connection across 400 volts three phase supply the value of resistance on each face of equivalent Delta will be
a.)5Ω
b.)45Ω✔
c.)50Ω
d.)75Ω
Q.29. Two coils connected in parallel across 100 volt supply mains take 10 ampere from the line the power dissipated in one coil is 600 watt what is the resistance of other coil
a.)5Ω
b.)15Ω
c.)25Ω✔
d.)35Ω
Q.30. Superposition theorem is essentially based on the concept of
a.) Duality
b.) Linearity✔
c.) Reciprocity
d.) Non linearity
Q.31. Torque of a single phase induction motor at synchronous speed is
a.) Zero
b.) Negative✔
c.) Positive
d.) Multiple
Q.32. Starting torque of an induction motor is proportional to
a.)1/2 supply voltage
b.)(supply voltage)1/2
c.)(supply voltage)
d.)(supply voltage)2✔
Q.33. An induction motor is in general is analogous to
a.) an auto transformer
b.) A two winding Transformer with its secondary open circuit
c.)  A two winding transformer with seconds short circuit✔
d.) A three winding transformer
Q.34. The slip of induction motor under full load is about
a.)0.1
b.)0.2
c.)0.3✔
d.)0.8
Q.35. The rated speed of an induction motor is 1410 RPM what is meant by the statement "the sleep' =1?
a.) The motor runs at synchronous speed
b.) Motor runs at rated speed
c.) Speed is high then synchronous speed
d.) Rotor is stationary✔
Q.36 If the auto transformer tapping 'K' is less than 1 starting torque of squirrel cage induction motor with the Transformer starter is
a.) K time starting torque
b.) K2 time starting torque✔
c.) 1/2 Time starting torque
d.)1/K2Time starting torque
Q.37 the direction of rotation of shaded pole motor is always toward the
a.) Main pole
b.) Shaded pole✔
c.) Salient pole
d.) Consequent
Q.38. Overload protection in Emmanuelle starting switch is provided by
a.) Dual element fuse
b.) Toggle switch
c.) Thermal activated device✔
d.) Snap action mechanism
Q.39. Single phase induction motor can be brought off as a composite of two motor mechanically coupled if one of these motor has slip 'S' then sleep of other motor is
a.)S
b.)(1-S)
c.)(2-S)✔
d.)0.55
Q.40. Single phase Universal motor can run on
a.)A.C.supply
b.)DC supply
c.) Both A and B✔
d.)Rectified DC only
Q.41. Hi speed alternator are driven by
a.) Diesel engine
b.) Steam turbines✔
c.) Hydraulic turbines
d.)None
Q.42. Carbon brushes are used in a DC machine because
a.) Karbonn lubricates and polishes the commutator✔
b.) Contact resistance is decreased
c.) Carbon is cheap
d.) Carbon is abundant
Q.43. Which motor has the best speed regulation
a.) Series
b.) Shunt
c.) Commutativity compound✔
d.) Differentially compound
Q.44. A comparatively  compound motor does not run at dangerous speed at light load because of the presence of
a.) Shunt winding✔
b.) Interpoles
c.) Series
d.) Compensating winding
Q.45 the AC armature winding of an alternator is
a.) Always star connected✔
b.) Star delta connected
c.) Generally Delta connected
d.) Pi connected
Q.46. Damper winding are used in alternator to
a.) Prevent hunting✔
b.) Achieve synchronism
c.) Reduce find age loss
d.) Reduce Eddy current loss
Q47. What can be found in a transformer with open circuit test
a.) Copper losses
b.) Turn ratio✔
c.) Total equivalent resistance
d.) Total equivalent leakage resistance
Q.48. The efficiency of a transformer will be at maximum when
a.) Leakage reactance of the two winding are equal
b.) Resistance of the two winding are equal
c.) Copper loss is equal to constant loss✔
d.) Copper loss is zero
Q.49. Combination of AC motor DC generator and exciter to provide adjustable voltage DC power to a DC motor
a.) Ward-Leonard system✔
b.) Half wave SCR adjustable voltage supply
c.) Compound motor
d.) Universal motor
Q.50. A series motor will over speed when
a.) The load is increased
b.) The armature circuit is open
c.) The field ID opened
d.) Load is removed✔
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Tuesday, 24 April 2018

Preview Question paper 1 (121to153)


Q.121 The function of snubber circuit is 
a.)Suppress dv/dt✔
b.)Increase dv/dt
c.)Decrease dv/dt
d.)None of these
Q.122 What is the dielectric of mica?
a.)200
b.)100
c.)3-8✔
d.)1-2
Q.123 What is the name of fluorscent material that give red colour fluorscent
a.)Zinc silicate
b.)Calcium silicate
c.)Zic silphide
d.)Magnesium silicate✔
Q.124 The noise resulting from vibration of lamination set by magnetic force is termed as 
a.) Magneto striction
b.)Boom
c.)Hum✔
d.)Zoom
Q.125 Galvanised steel is generally used as
a.)Stray wire
b.)Earth wire
c.)Structural component
d.)All of the above✔
Q.126 When R2 is rotor resistance , X2 the rotor reactance at supply frequency and s the slip, then the condition for the maximum torque under running codition will be 
a.)sR2=X2
b.)R2=s2X2
c.)R2=s2X22
d.)R2=Sx2✔
Q.127 Which of the following method are suitble for the speed control of squirrel cage induction motor
i.)Voltage contorl
ii.)Frequency control
iii.)Pole changing method
iv.)Rotor resistance control
Select the correct answer using the code given below
a.)2,3 and 4
b.)1,2 and 3✔
c.)1,3 and 4
d.)2 and 4
Q.128 In star delta starting  of an induction motor
a.)Reduce voltage is applied to the rotor
b.)Applied voltage per stator phas is 57.7% of the line voltage✔
c.)Line voltage is 57.7% of stator voltage
d.)resistance is inserted in the rotor
Q.139 Which is following methods of speed control is not affected through stator side
a.)Change of rotor resistance
b.)Change of number of pole
c.)Change of supply voltage
d.)Change of supply frequency✔
Q.130 The wound rotor type induction motor is used for ________speed operation
a.)Constant
b.)Maximum
c.)Minimum
d.)Variable✔
Q.131 Pole changing method is suitable for ______type induction motor
a.)Wound rotor
b.)squirrel cage✔
c.)linear
d.)None of these
Q.132 Buchholz's relay protect from
a.)Winding to winding fault
b.)All type of internal fault✔
c.)Turn to turn fault
d.)None of these
Q.133 A capacity of cranes is expressed in
a.)Span
b.)Type of drive
c.)Tonnes✔
d.)any of the above
Q.134 A saturable core reactor is basically a
a.)Variable resistor
b.)Step down transformer
c.)Thermal relay
d.)Variable impedence✔
Q.135 In case of contactor , overheating of contact is caused from any of the following except
a.)Excess pressure✔
b.)High induction load
c.)Copper oxide on contact
d.)Carrying load for long time
Q.136 In case of low and medium voltage circuit permissible voltage variation is 
a.)1%
b.)5%✔
c.)10%
d.)15%
Q.137 The earth potential is taken as
a.)Infinite
b.)Supply voltage
C.)1Volt
d.)Zero✔
Q.138 MIG welding is 
a.)Mild steel inert gas
b.)Medium inert gas
c.)Mximum inner depth gas welding✔
d.)Matel inert gas
Q.149 For both lap and wave windings, there are a many commutator bars as the number of 
a.)Poles
b.)Slots
c.)Armature conductor
d.)Winding element✔
Q.140 A wir of rsisitance R has its length and cross-section both doubled. Its resistance will become
a.)0.5R
b.)R✔
c.)2R
d.)4R
Q.141 5×1016 electron pass across the section of a conductor in 1 minute and 20 seconds. the current following is
a.) 0.1 mA✔
b.) 1 mA
c.) 10 mA
d.) 100 mA
Q.142 Three element having conductance G1, G2 and G3 are connected in parallel. Their combined conductance will be 
a.) (G1+G2+G3)-1
b.) G1+G2+G3✔
c.)1/G1+1/G2+1/G3
D.)(1/G1+1/G2+1/G3)-1
Q.143 Which of the following has negative temperature coefficient
a.)Electrolytes✔
b.)Brass
c.)Copper
d.)Silver
Q.144 Which of the following has positive temperature coefficient
a.)Germanium
b.)Gold✔
c.)Paper
d.)Rubber
Q.145 The substance used to slow down the speed of neutrons in a nuclear reactor during fission reaction is called
a.)Coolant
b.)Liquid
c.)Moderator✔
d.)Control element
Q.146 Stator core of an induction motor is made of
a.)Laminated cast iron
b.)mild steel
c.)Silicon steel stamping✔
d.)Softwood
Q.147 Slipring of a face wound induction motor are made of
a)Wood
b.)Steel
c.)copper✔
d.)cast iron
Q.148 There is no electrical connection between stator and rotor, still power is transferred from stator to rotor through
a.)Magnetic flux✔
b.)Air
c.)Water
d.)Magnet
Q.149 The plates of lead acid battery is made of 
a.)Rolled zic copper alloy
b.)Perforated nickel-cadmium alloy✔
c.)Cast animonial lead alloy
d.)None of these
Q.150 The lead acit battery , during charging
a.)Anod become whitish in color
b.)Voltage drop
c.)The cell give out energy
d.)Specific gravity of acid increases✔
Q.151 The condition of fully charged lead acid battery can be ascertained by
a.)Specific gravity of electrolyte
b.)Voltage
c.)Gassing
d.)Any of the above✔
Q.152 A circuit that operate in such a way thats output is high when all ita input are high
a.)OR
b.)NAND
c.)NOR
d.)AND✔
Q.153 How many input does a full adder have 
a.) 2
b.) 4
c.) 8
d.) 3✔
at No comments:

Preview Question paper 1 (101-120)


Q.101. A. alternator is supplying a load of 300kW of a power factor of 0.6 lagging . If the power factor is raised to unity , how many kilowatts can alternator supply for the same kVA loading
a.)100kW
b.)200kW✔
c.)300kW
d.)500kW
Q.102. for transmission line which of the following relation is correct  ?
a.)AD-BC=1✔
b.)AC-BD=1
c.)BA-CD=1
d.)BC-AD=1
Q.103. match the following
Types of transmission line types of relay
 preferred
i. Short line               1. Ohm relay
ii. Medium line          2. Reactance relay
iii. Long line.               3. Mho relay
a.) a-1, b-2,c-3
b.)a-2,b-1,c-1✔
c.)a-3, b-2,c-1
d.)a-1,b-1,c-1
Q.104. High Voltage Transmission (HVDC transmission) is mainly used for
a.)Bulk power transmission for very long distance ✔
b.)Interconnecting to system with the same nominal frequency
c.)Eliminating reactive power requirement in the operation
d.)Minimizing harmonics at the converter station
Q.105. Ferranti effect is seen in which transmission line?
a.)Long transmission line ✔
b.)Medium transmission line
c.)short transmission line
d.) Both A and B
Q.106. SCR is a device
a.)Semi-controlled✔
b.)Full-controlled
c.)Uncontrolled
d.)None of these
Q107. For a 3Φ transmission line transmission efficiency of a line decrease with
a.)Increase in load power factor
b.)Decrease in load power factor✔
c.)Does not vary with power factor
d.)Increase in Load current
Q.108. 3Φ synchronous  motor has
a.)High starting torque
b.)Low starting torque
c.)No starting torque✔
d )Low starting current
Q.109. In a synchronous motor
a.)The rotor mmf and stator mmf are stationary with respect to each other ✔
b.)Stator mmf rotates slightly faster then rotor mmf
c.)Rotor mmf rotates slightly faster in comparison to stator mmf
d.)None of these
Q.110. When does a synchronous motor operate with leading power factor electric current?
a.)While it is under excited
b.)While it is over excited✔
c.)While it is critically excited
d.)While it is heavily loaded
Q.111. The use of _____instrument is merely confined within laboratories as standardizing instrument
a.)Indicating
b.)Absolute✔
c.)Recording
d.)Integrating
Q.112. Slip of induction motor is 0.02 and the stator supply frequency is 50Hz . The frequency of rotor induced e.m.f. will be
a.)10Hz
b.)50Hz
c.)1Hz✔
d.)25Hz
Q.113. The watt meter reads 30.34W. The absolute error in the measurement is 2.22W . What is the true value of power
a.)32.56W✔
b.)28.12
c.)25.45
d.)None of these
Q.114.A resistor and an  inductor are connected in series across a voltage source. which two parameter in that circuit decreases if the frequency of source increase
a.)VL and Z
b.)Z and I
c.)VR and I✔
d.)VL and VR
Q.115. Diatance relays operation is depend upon
a.)Ratio of current to current
b.)Ratio of voltage to current✔
c.)Ratio of voltage to voltage
d )Ratio of voltage to resistance
Q.116. Harmonic distortion of signal is produced in RC  coupled amplifier . The probable  cause is
a.)Transistor itself✔
b.)Power supply Vcc
c.)Coupling capacitor Cc
d.)Biasing resistor R1 & R2
Q117. When 't' is thickness of sheet , the top diameter of spot welding is usually
a.) 2t
b.) t
c.) √t✔
d.) 1/t
Q.118. For tramways, the return circuit is through
 a.)Cable
b.)Rails✔
c.)Neutral
d.)Common earthing
Q 119. The rectifier which require the minimum amout of filtering is
a.)Half wave rectifier
b.)Full wave rectifier
c.)Voltage doubler
d.)SCR half wave rectifier✔
Q. 120. A device whose chercterstics are close to ideal voltage source
a.) Diode
b.) FET
C.)Transistor in CB
d.)Zener diode✔
at No comments:

Preview Question paper (1) 81to 100


Q.81. The voltage of super tension cable is up to
a.) 132kV
b.) 66kV
c.) 33kV✔
d.) 220kV
Q.82. Which distribution scheme is employed in metropolitan areas
a.)Radial system
b.)Interconnected system✔
c.)Ring system
d.)None of these
Q.83. A line which connect between substation and distribution transformer
a.)Secondary feeder
b.)Primary feeder✔
c.)Sub transmission feeder
d.)None of these
Q.84. A ratio of average load to maximum load is called.
a.)Plant use factor✔
b.)Diversity factor
c )Load factor
d.)Operation factor
Q.85. In 3Φ Induction motor in order to eliminate cogging the number of stator slot must be
a.)Unequal to number of totor slot and skewed in shape✔
b.)Equal to number of rotor slot
c.)An integral multiple of number of rotor slots
d.)Either B or C
Q.86. A slipring motor run at 290 rpm at full load, when connected to 50Hz supplym Determine the number of pole and slip
a.)P=20, S=3.33%✔
b.)P=40, S=5.79%
c.)P=60, S=0.96%
d.)P=50, S=4.43
Q.87. The rotor of 3Φ induction motor has an impedance of 0.4+j4 ohm per phase at stand still the maximum torque occur at a slip of ______
a.) 10%✔
b.) 15%
c.) 25%
d.) 50%
Q.88. Select the wave that has the least value of form factor
a.)Square wave ✔
b.)Rectangular wave
c.)Triangular wave
d.)Sine wave
Q.89. In a commutation circuit employed to turn off the SCR , satisfactory turn off is obtained when
a.)Circuit turn off time < device turn off time
b.)Circuit turn off time > device turn off time✔
c.)Circuit time constant > device turn off time
d.) Circuit time constant < device turn off time
Q.90. Which of the flowing is true SCR ?
a.)It can block forward voltage and conduct in forward direction
b.)It can block both forward and reverse voltage but conduct in reverse
c.)It can block reverse voltage and conduct in both direction
d.)It can block both forward and reverse voltage but conduct in forward direction✔
Q.91. Holding current is
a.)The minimum current which must pass through the device to remain in th 'ON' stage ✔
b.)Maximum current below which anode current must fall for turning 'ON'
c.)Minimum anode current above which thyristor gets turn 'OFF'
d.)Minimum current below which anode current must fall for turning 'ON'
Q.92. The trapped energy of an inductive load can be feedback to the input supply through a diode known as
a.)Zener diode
b.)Free wheeling diode✔
c.)Power diode
d.)None of these
Q.93. Insulated cable are usually rated by their
a.)Operating Voltage
b.)Operating Voltage and Highest operating temperature✔
c.)Operating temperature
d.)Cost
Q.94.Synchronous machine
a.)Can operate at unity power factor
b.)Can operate at leading power factor
c.)Can operate at lagging  power factor
d.)Can operate at any power factor✔
Q.95. A winding having number of slots equal to number of poles then this winding is called
a.)Concentrated winding✔
b.)Short pitch winding
c.) Full winding
d.)distributed winding
Q.96 Which alternator are more suitable for high speed system
a.)Salient pole
b.) Non salient pole✔
c.)Both A and B
d.)None of these
Q.97.In a Δ connected generator , all of the phase voltage are
a.)Zero
b.)Equal in magnitude✔
c.)One third of total
d.)One sixth of total
Q.98. A ohmmeter is connected across an inductor and the pointer indicate zero ohms .The inductor is
a.)Good
b.)Open
c.)Shorted✔
d.)Partially shorted
Q.99.Moving iron instrument is used
a.)AC and DC both✔
b.)AC only
c.)DC only
d.)None of these
Q 100. For increasing the range of an ammeter, connect
a.)A high voltage resistance in series with the ammeter coil.
b.)A high valur resistance in parallel with the ammeter coil.
c.)A low value resistance in parallel with the ammeter coil.✔
d.)A low value resistance in series with the ammeter coil.
at No comments:

Preview Question paper (1) 41-80


Q.41. The pressure coil of an induction type energy metre is
a.) Highly resistive
b.) Highly inductive✔
c.) Less resistive
d.) Less inductive
Q.42. Beam of electrons in a CRT emanates because of
a.) Secondary emission
b.) Diffusion
c.) Post acceleration
d.) Thermoionic emission✔
Q.43. When conductor are in horizontal formation type of Guard used is are
a.)Cradle Guard✔
b.) Cage guard
c.) Both A and B
d.) Box Guard
Q.44 in cloth washing machine and refrigerator which motor are preferred
a.) DC cumulative compound motor
b.) Slip ring induction motor
c.) Stepper motor
d.) Universal motor✔
Q.45 in DC transmission line
a.) There are no effects due to Inductive and capacitive reactance✔
b.) The effects of Inductive and capacitive reactance are greater than in an AC transmission line of the same rating
c.) It is necessary for the sending end and receiving and to be operated in synchronism
d.) Power transfer capability is limited by stability consideration
Q.46. How many relays are used to detect the inner phase fault
a.) One
b.) Two
c.) Three✔
d.) six
Q.47 the Corona loss on particular system at 50 Hz is 1 kW/km per phase. what is the corona loss at 60Hz in kW/km per phase
a.) 0.83
b.) 1.0
c.) 1.13✔
d.) 1.2
Q.48. A single phase transformer when supplied from 220 V 50Hz Eddy current loss of 50W, if transformer is connected to voltage 430V 50Hz then Eddy current loss will be
a.) 112.50Watt
b.) 191.01Watt✔
c.) 181.56Watt
d.) 205.67Watt
Q.49. Strain insulator is used for voltage level of
a.) >33kV
b.) <11kV✔
c.) >66kV
d.) 132kV
Q.50. Sensitivity factor of a strain gauge is normally of the order of
a.) 1.5-2.0✔
b.) 1-1.5
c.) 0.5-1
d.) 5-10
Q.51. The decimal equivalent of hexadecimal number of2AOF is
a.)17670
b.)17607
c.)10767✔
d.)17068
Q.52.when the magnetic flux and the area under its influence are known, how can one calculate the magnetic flux density
a.)B= Φ×A
b.)B= Φ/A✔
c.)B=A/ Φ
d.) B= Φ×A2
Q.53. the lifting power of an electromagnet can be increased by
a.) Increasing the flux density✔
b.) Decreasing the core area
c.)Decreasing the core length
d.)All of these
Q.54. When the current flow in a conductor, heat is produce because
a.)Heat ∝I2✔
b.)Of electronic collision
c.)Of interatomic collision
d.)Of Joule's Law
Q.55. Conductance is analogous to
a.)Flux
b.)Reluctance
c.)Permeance✔
d.)None of these
Q.56.Transformer is a
a.)Rotating device
b.)Static device✔
c.)Magnetic device
d.)None of these
Q.57. The voltage transformation ratio is
a.)E1/E2
b.)N1/N2
c.)E2/E1✔
d.)None of these
Q.58. Every instant the direction of secondary current in a transformer must be such as to oppose any change in flux. This is in accordance with
a.)faraday's law
b.)Joule's law
c.)Lenz's law✔
d.)Coulomb's law
Q.59. What is the efficiency of transformer compared with that of electrical motor of same rating
a.)Much smaller
b.)Somewhat smaller
c.)About the same
d.)Much higher✔
Q.60.What is typical used of an auto transformer
a.)Isolating transformer
b.)Toy transformer
c.)Control transformer
d.)Variable transformer✔
Q.61. The commercial efficiency of a transformer while a open circuit
a.)Zero✔
b.)Maximum
c.)Either zero or 100%
d.)None of these
Q.62. The special silicon steel is used for lamination because
a.)Eddy current loss are reduced
b.)Hysteresis loss are reduced ✔
c.)Both loss are reduced
d.)None of these
Q.63.Which parameter does not change during transformation action in transformer
a.)Voltage
b.)Frequency✔
c.)Current
d.)None of these
Q.64. An ideal transformer is one which has
a.)No winding resistance
b.)No leakage reactance
c.)No losses
d )All of above✔
Q.65. The input power under no load condition of transformer consist of
a.)Core losses in transformer✔
b.)Core losses and very small amount of copper loss in primary
c.)Copper loss in transformer
d.)Significant copper loss along with negligible core losses
Q.66. In one 132/33kV transformer, the LV resistance is 0.02 per unit . The resistance referred to HV side is 
a.)0.08pu
b.)0.02pu✔
c.)0.16pu
d )0.01pu
Q.67. Lamination of transformer core is made of
a.)Cast iron
b.)Silicon steel✔
c.)Wrought iron
d.)Cast steel
Q.68. Oil is provided in an oil filled transformer
a.)Both cooling and insulation✔
b.)Insulating
c.)Lubrication
d.)Cooling
Q.69. Air core transformer as compared to iron core transformer has
a.)More copper loss
b.)Less magnetic core loss
c.)More magnetic core loss
d.)No magnetic core loss✔
Q.70. CRGO steel is used in the transformer to reduce
a.)Eddy current loss
b.)Ohmic loss
c.)Both eddy current and hysteresis loss
d.)Hysteresis loss✔
Q.71.If input of a ttansformer is square wave the output will be
a.)Pulsed wave✔
b.)Square wave
c.)Triangular wave
d.)Sine wave
Q.72. Two transformer with identical rating are designed with flux densities of 1.2 and 1.4Wb/m2 respectively. The weight of the first transformer per kVA is
a.)Less then that of second transformer
b.)Equal to that of second transformer
c.)More then that of second transformer✔
d.) None of these
Q.73. The flux involved in the emf equation of a transformer has
a.)RMS value
b.)Maximum.value✔
c.)Averge value
d.)Total value
Q.74. The no load current in a transformer lags the applied voltage
a.) 75°✔
b.) 0°
c.) 90°
d.) 115°
Q.75. The leakage flux in a transformer depends upon
a.)The applied voltage
b.)The load current✔
c.)The frequency
d.)The mutual flux
Q.76. For satisfactory parallel operation of two transformer which of the following condition is most essential
a.) Polarities of all transformer operated in parallel must be connected properly ✔
b.) Percentage of impedence of transformer operated in parallel must be same
c.) Voltage ratio of all transformer operated in parallel must be same
d.) MVA rating of all transformer operated in parallel must be same
Q.77. If a transformer has turn ratio K the primary and secondary current I1 and I2 respectively and magnetizing  current and core loss component of no load current Iu and  Iw respectively then
a.) I1=K.I2+Iw
b.) I1=K.I2+Iw+Iu✔
c ) I1=K.I2+Iu
d.  I1=K.I2
Q.78. Which of the follwing  transformer insulating oil generally used in india
a.)Paraffin based insulating oil✔
b.)Naphtha based insulating oil
c.)Aromatic based insulating oik
d.)Olefin based insulating oil
Q 79.Winding conductor of an electrical power transformer are mainly insulated by
a.)Cotton insulating
b.)Rubber insulating
c.)Paper insulating✔
d.)Wooden insulating
Q.80 The charging current in a cable
a.)Lead voltage by 120°
b.)Lag voltage by 90°
c.)Lag voltage by 120°
d.)Lead voltage by 90°✔
at No comments:

Preview Question paper (1) 01-40

Q.1. At what frequency corona loss is more 
a.) 50Hz
b.) 60Hz
c.) 25Hz
d.) 100Hz✔
Q .2.  Insulated cable are usually rated by their
a.) Operating voltage
b.) Operating voltage and highest operating temperature✔
c.) Operating temperature
d.) Cost
Q.3. Class B insulation can bear a temperature ( in degree centigrade) up to
a.)130✔
b.)120
c.)105
d.)90
Q.4. Excess 3 code is known as
a.) Weighted code
b.) Cyclic redundancy code
c.) Self complementing✔
d.) Algebric code
Q.5. To convert a moving coil galvanometer into an ammeter we must connect a
a.) Low resistance in series
b.) High resistance in series
c.) Low resistance in parallel✔
d.) High resistance in parallel
Q.6. Specific resistance of a conductor depend upon
a.) Length of conductor
b.) Nature of conductor material✔
c.) Diameter of conductor
d.) All A B and C
Q.7. A wire length R is half the length of a wire S of similar material.The resistance of R to that S is
a.) 8:1
b.) 1:1
c.) 2:1✔
d.) 4:1
Q.8. The type of slots used in armature of a High Voltage DC motor is
a.) Closed type
b.) Semi closed type✔
c.) Open type with dovetail
d.) Open type with tapered slot
Q.9. m-cells each of emf E are connected in series . The effective emf of combination will be
a.)E
b.)mE✔
c.)E/m
d.)m/E
Q.10. Watt hour is the unit of
a.) Electric power
b.) Electric capacity
c.) Electric energy✔
d.) Electric charge
Q.11. The unit of electrical energy is
a.) Watt-sec
b.)Joule
c.)kWh
d.)All A,B and C✔
Q.12. Atmospheric pressure is measured with a
a.) Hydrometer
b.) Barometer✔
c.) Hygrometer
d.) Altimeter
Q.13. When the speed of a body is doubled its kinetic energy becomes
a.) Double
b.) Half
c.) 4 time✔
d.) 1/4
Q.14. Rocket works on the principle of conservation of
a.) Mass
b.) Energy
c ) Momentum✔
d.) Velocity
Q.15. Bleaching action of chlorine is due to
a.) Reduction
b.) Hydrogenation
c.) Chlorination
d.) Oxidation✔
Q.16. The Solar Eclipse occur when
a.) The sun comes in between the moon and the earth
b.) The earth comes in between the sun and the moon
c.) The moon comes in between the sun and the earth✔
d.) None of the above
Q.17. Material which store energy are classified as
a.) Dielectric material✔
b.) Insulating material
c.) Magnetic material
d.) None of these
Q.18. Variable resistor are
a.) Carbon resistor
b.) Thin film resistor
c.) Nichrome resistor
d.) Wire wound resistor✔
Q.19. The dielectric strength of Transformer oil should be
a.) 5kV
b.) 30kV✔
c.)100kV
d.)132kV
Q.20. Register with negative temperature coefficient are
a.) Ballast resistor
b.) Wire wound resistor
c.) Thermistors✔
d.) None of these
Q.21. In a diode the cut in voltage and forward voltage drop are
a.)0.7,07V
b.)0.7, 1V✔
c.)0.7, 0.6V
d.)1, 0.7V
Q.22. In BJT
a. β= α/ α+1
b.) α= β/ β -1
c.) α= β+1/ β
d.) β= α/ α -1✔
Q.23. The function of a filter in rectifier is to
a.) Limit the total current in the rectifier
b.) Limit the peak voltage of the rectifier
c.) Limit the DC current
d.) Reduce the ripple voltage in the output✔
Q.24. Thyristor can be termed as
a.) DC switch✔
b.) AC switch
c.) Either A or B
d.) Square wave switch
Q.25. An 0-10A ammeter  has a guaranteed accuracy of 1% of full scale deflection the limiting error while reading 2.5 A is
a.)1%
b.)4%✔
c.)2%
d.)none of these
Q.26. Frequency can be measured using
a.) Wein's Bridge✔
b.) Schering Bridge
c.) Heaviside Campbell's Bridge
d.) Maxwell's Bridge
Q.27. A strip Chart recorder is
a.) An active transducer
b.) An inverse transducer
c.) An output transducer
d.) Both B and C✔
Q.28. A photoconductive cell may be called
a.) Photoresistive cells
b.) Photo resistor
c.) Light dependent resistor
d.) All of above ✔
Q.29. In how many different modes a universal shift resistor operate
a.) 2
b.) 3
c.) 4✔
d.) 5
Q.30 In the CMOS inverter the power dessiption is
a.) Low only when Vin is low
b.) Low only when Vin is high
c.) High during dynamic operation
d.) Low during dynamic operation✔
Q. 31. A Boolean algebra F= (A+B) (Ā+C) then
a.) F=AB+ĀC
b.)F= AB+ĀB
c.)F=AC+ĀC✔
d.)F=AA+ĀB
Q.32. The 555 timer has _______ number of modes of operations
a.) 2
b.) 3✔
c.) 4
d.) 5
Q.33. The current drawn by a 220 V DC motor of armature resistance 0.5 Ω and back e.m.f. 200V is
a.) 40A✔
b.) 44A
c.) 400A
d.) 440A
Q.34. Crawling in induction motor is caused by
a.) Improper design of stator lamination
b.) Low voltage supply
c.) High load
d.) Harmonics developed in motor✔
Q.35. A 500 MW, 13.8 kV  star Connect synchronous generator at 0.8 PF will deliver a full load current of
a.) 12.1 kA
b.) 21.0kA
c.)26.15kA✔
d.)46.5kA
Q.36. What is the approximate efficiency of a normal thermal power station
a.)30-40%✔
b.)45-55%
c.)20-25
d.)60-70%
Q.37. Generating station has maximum demand of 30 MW load factor of 60% and plant capacity 50% the reverse capacity of plant is
a.) 5MW
b.) 4MW
c.) 6MW✔
d.) 10MW
Q.38. Bundled conductor are used for EHV transmission this primarily for reducing
a.) Corona loss✔
b.) Surge impedance of line
c.) Voltage drop across line
d.)I2R Losses
Q.39. Which one of the following is to most suitable device for a DC-DC converter
a.)BJT
b.)GTO✔
c.)MOSFET
d.)Thyristor
Q.40. Superposition theorem is not applicable for
a.) Voltage calculation
b.) Bilateral elements
c.) Power calculation✔
d.) passive element
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Power system MCQ

Q 1 . In Power station practice "spinning reverse" is  (a) Reverse generating capacity that is in operation but not in...