Solved LMRC Electrical JE paper 2020



1. Which of the following function is not performed by a transformer?




... Answer is B)
Transfers electric energy with a change of frequency

The function of a transformer is to step up or step down alternating voltage while maintaining power at the same level. Therefore, a change in voltage causes reverse change in current.
Transfers electric energy with a change of frequency.
.


2. The ratio of rotor copper loss with rotor output is




... Answer is D)
S/(1-s).


3. Demand factor =




... Answer is D)
Maximum demand of a system / Total connected load on the system.


4. It is a single-crystal semiconductor material with no other types of atoms within the crystal.




... Answer is B)
Intrinsic semiconductor.


5. The amount of electrical energy stored for every kilogram of battery mass is defined as___




... Answer is A)
Specific power.


6. A ________ is an npn or pnp sandwich of semionductor materials




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


7. Which of the following is NOT a part of automatic control system




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


8. In which of the following motors is torque produced due to the tendency of the rotor to align itself in the minimum reluctance position when the speed of the motor is close to the synchronous speed?




... Answer is C)
Reluctance motor.


9. _________ is the flux-producing ability of an electric current in a magnetic circuit




... Answer is C)
magnetomotive force.


10. ________ are used in control systems to attain the mechanical matching of the motor of the load.




... Answer is C)
Gear Trains.


11. In simple series RLC circuit, _______ corresponds to the infinitre capacitance C= infinity and I = 0.




... Answer is C)
Purely resistive circuit.


12. convert (0.7854)10 to binary.




... Answer is C)
(0.1100)2.


13. Which law states :The sum of volatges around a closed loop circuit is equal to zero.




... Answer is C)
Kirchoffs volatge law.


14. In _______ the susceptibility will decrease with increase in teperature and they have relatively small susceptibility at all tempeartures.




... Answer is A)
Anti ferromagnetic materials.


15. ________ possess NO free carge carriers and thus are non conductive




... Answer is C)
Insulators.


16. The cosine of the angle between useful power and total power is ________




... Answer is C)
Power factor.


17. _________ has the property of storing potential energy.




... Answer is A)
A spring.


18. A resistor capable of incrementing and/or decrementing its contents.




... Answer is A)
Counter.


19. What is the motor load factor when a motor of 20 hp drives a constant 15hp load whenever it is ON?




... Answer is A)
75%.


20. Following type control system uses the concept of an open loop system as its forward path but has one more feedback loops or path between its output and its input.




... Answer is C)
Closed loop control system.


21. The diffrence between the tooth space and tooth width in mechanical systems which is essential for rapid working gear transmission is known as ________ .




... Answer is C)
Backlash.


22. Fermi level energy for n-type extrinsic semiconductors lies ________ .




... Answer is A)
Close to the conduction band.


23. A series RLC circuit with L=160 mH,C= 100mF and R= 40 ohm is connected to sinusoidal voltage V(t)= 40 sin omegat ,with omega = 200rad/s.what is the impedance and phase angle of the circuit?




... Answer is A)
43.9 ohm,-24.2 deg.


24. Which of the following type of motors has the armature placed in rotor and the field winding replaced by permanent magnet poles fixed due to the stator to produce the required magnetic field?




... Answer is C)
Permanent magnet DC motors.


25. Which of the following is an advantage of an AC transmission system?




... Answer is B)
The alternating voltages can easily be stepped up and down.


26. The systems which control the motion of the electrical machines are known as _________.




... Answer is D)
Electrical drives.


27. _______ are those whose field are energized from an independent external source of DC current.




... Answer is D)
Separately excited generator.


28. For ______ the output C(s) of the system is equal to transfer function of the system.




... Answer is A)
Impulse response.


29. A three phase IM,six poles ,50 Hz is supplied by three phase source,the rotor rotates at 800 rpm.calculate the slip




... Answer is A)
0.2.


30. ________ is defined as maximum current can flow through the breaker from time of occuring short circuit to the time of clearing the short circuit without any permanent damage in the circuit breaker.




... Answer is B)
short circuit breaking current.


31. Radar tracking systems,missile tracking systems and machine tool position control are applications of ______ .




... Answer is C)
a position control system.


32. _________ is equal to the current passing through short circuited output terminals.




... Answer is D)
Norton's current.


33. _________ of measurement is a measure of the change in instrument output that occurs when the quantity being measured changes by a given amount.




... Answer is A)
Sensitivity.


34. In a split phase machine ,the main winding has low resistance but high resistance whereas the starting winding has a ________ resistance,but _______ resistance.




... Answer is B)
High,Low.


35. Which among the following is an electromagnetic transducer commonly used to convert angular position of shaft in to electrical signal and which produces an output voltage depending upon the angular position of the rotor.




... Answer is A)
Synchro.


36. Whic of the following is a measure of the flow of electric charge over time?




... Answer is D)
Current.


37. Which of the following acts as a covering and it provides protection and mechanical strength to all the inner parts of the induction motor?




... Answer is A)
Stator frame.


38. A _______ is combined unit of ampere meter,voltmeter and ohmmeter.




... Answer is D)
Multimeter.


39. In motor operations,if at any time _______, the motor will accelerate.




... Answer is A)
Te > Tl.


40. _______ is performed when the diode is froward biased during the negative half-cycle of the input in Negative diode clipping circuits.




... Answer is D)
Negative Half wave rectification.


41. Servomeachanisms are ______ whwre the feedback signals are used to control position,speed,velocity,acceleration etc.




... Answer is C)
closed loop control systems.


42. __________ is the process of plating one metal onto other by hydrolysis most commonly for decorative purposes or to prevent corrosion of metal.




... Answer is D)
Electroplating.


43. The amount of electrical energy consumed by a circuit over a period of time is ________ .




... Answer is D)
Watt - hour.


44. The function of this element is to manipulate the signal presented to it preserving the original nature of the signal.




... Answer is D)
Variable manipulation element.


45. ________ consists of a high performance permanent magnet motor,often with an integral tachogenerator and a chopper type power amplifier module in D.C motor.




... Answer is D)
DC servo drives.


46. Which of the following is the most common protection device that can make or break the circuit either manually or through remote control under normal operating conditions?




... Answer is C)
Circuit breaker.


47. ________ are usually difficult to treat mathematically and there are no general methods available for solving a wide class of these systems.




... Answer is A)
Non-linear control systems.


48. It is defined as the degree of the measurement system.It indicates changes in measure and without any dynamic error.




... Answer is D)
Fidelity.


49. Which of the following is a unit of voltage?




... Answer is A)
Joule/Coulomb.


50. Which of the following provides leading current which neutralize the lagging inductive component of load current thus power factor of the load circuit is improved?




... Answer is C)
Static capacitors.


51. _________ is an instrument used for measuring electrical potential difference between two points in a electric circuit.




... Answer is A)
Voltmeter.


52. In intrinsic semiconduvtors,the number of electrons is _________ the number of holes.




... Answer is C)
Equal to.


53. _________ can be defined as an abnormal connection of very low impedance between two points of different potential whether made intentionally or accidentally.




... Answer is B)
short circuit faults.


54. Mixed node is defined as :




... Answer is C)
A node which has both incoming and outgoing branches.


55. The function of the ________ is to facilitate collection of current from the armature conductors.




... Answer is B)
Commutator.


56. In a capacitor filter rectifier circuit, ________ the capacitance value,higher will be the power factor.




... Answer is A)
Lower.


57. _________ employs mesh analysis to find the different mesh currents by finding the IR products in each mesh.




... Answer is C)
KVL.


58. In which of the following,vibration galavanometer tuneable amplifier and headphones are used?




... Answer is D)
AC bridges.


59. __________ is also known as inverter.




... Answer is A)
NOT gate.


60. In industries, ___________ is required for the melting of metals,moulding of glass,enamelling of copper,baking of insulator and welding etc.




... Answer is C)
electric heating.


61. High resistances are provided with a guard terminal.This guard terminal used to:




... Answer is C)
Bypass the leakage current.


62. __________ of the consumers may be either connected to the distributors or subdistributors ipon the position and agreement of consumers.




... Answer is B)
Service mains.


63. The poles faces shaped to fit the curvature of the armature are known as the _______ .




... Answer is C)
Pole shoe.


64. Control system in which the output has no influence or effect on the control action of the input signal is called




... Answer is B)
open loop control system.


65. some metal lose all resistivity abruptly and completely at some low temp. above 0K.This phenomena is called




... Answer is B)
Superconductivity.


66. The most conventional method of generating electric power with reasonably high efficiency:




... Answer is A)
Thermal power.


67. The ratio of electrical energy supplied by a battery to the amount of electrical energy required to return it to the state before discharge is defined as _________.




... Answer is A)
Energy efficiency.


68. Which of the following is NOT an example of a secondary instrument?




... Answer is B)
Tangent galvanometer.


69. The instrument which use a permanent magnet for creating a stationary magnet field between which the coil moves is known as a ________.




... Answer is A)
PMMC instrument.


70. Which of the following welding processes uses a continously fed electrode through a welding gun and the operator needs to pull a trigger in order to feed the consumable electrode through?




... Answer is C)
Gas metal arc welding.


71. Which part of the induction motor among the following cariies a 3-phase winding and is fed from 3-phase supply?




... Answer is B)
Stator.


72. Conduction of current in both directions in an element(eg:Resistance,inductance,capacitance) with the same magnitude is termed as _________.




... Answer is A)
Bilateral element.


73. Which of the below is not a merit of static relay?




... Answer is D)
Long life.


74. _________ finds the voltage potentials at different nodes that provide a common connection for two or more circuit components in a circuit.




... Answer is C)
Nodal voltage analysis.


75. The _________ determines the ability of the transformer to provide the constant voltage for variable loads.




... Answer is B)
voltage regulation of a transformer.


76. __________ is a machine that converts mechanical energy into electrical energy.




... Answer is C)
generator.


77. ____________ is a analytical method used to change a complex circuit into a simple equivalent circuit of a single resistancein series with a source voltage.




... Answer is B)
Thevenins theorem.


78. A voltmeter has resistance of 2000 ohm when it is connected across a DC circuit its power consumption is 2mW,suppose this voltmeter is replaced by a voltmeter of 4000 ohmresistance,the power consumption will be:




... Answer is D)
1 mW.


79. In _________ materials each atom has a relatively large dipole moment,caused primarily by uncompensated electron spin moment.




... Answer is C)
Ferromagnetic.


80. Due to its smooth rotor,the following motor operates quitely and does not suffer from magnetic pulsations caused by slots salient poles that are present in the rotors of other motors.




... Answer is A)
Hysteresis motor.


81. For percentage differential protection or normal differential protection,the __________ in the primary and secondary winding should be same.




... Answer is D)
current transformer ratio.


82. The following have high electrical resistance and essential in order that the current drawn by them is small and consequently the power absorbed is small.




... Answer is B)
Voltmeters.


83. Calculate the Ie for a transistor that has adc=0.98 and Ib = 100mA.




... Answer is A)
5 mA.


84. A _______ of a system is a pictorial representation of the functions performed by each component and the flow of the signals.




... Answer is B)
Block diagram.


85. In which material , a magnetic field induces a magnetic moment that opposes the very magnetic field that actually causes it.




... Answer is C)
Diamagnetic.


86. A good insulating material should not posses




... Answer is A)
Non uniform viscosity.


87. A _________ is a device used in electrical power systems and telecommunication systems to protect the insulation and conductors of the system from the damaging effects of the lightning.




... Answer is A)
Lightning arrestor.


88. Which of the following class of insulating materials include cotton,silk,paper,cellulose,wood etc




... Answer is D)
Class Y.

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