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

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✔

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✔

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✔