483_1_ELECTRICAL_PAPER_80M.pdf

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Electrical Engineering & Allied

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Q-1 The purpose of providing dummy coils in a wave wound dc machine armature is to

(A) enhance flux density. (B) amplify voltage.

(C) mechanical balance for the rotor. (D) reduce eddy current loss.

Q-2 The emf generated by a dc generator may be increased by increasing the

(A) speed of rotation. (B) excitation.

(C) armature length. (D) either (a) or (b).

Q-3 Specific resistance of conductor depends upon

(A) dimentions of the conductor. (B) composition of conductor material.

(C) resistance of the conductor. (D) None of above.

Q-4 Static electricity is produced by

(A) Induction. (B) friction.

(C) Chemical reaction. (D) both induction and friction.

Q-5 In a dc generator,demagnetizing component of armature reaction causes

(A) reduction in generated emf. (B) increase in speed.

(C) sparking trouble. (D) none of the above.

Q-6 The number of line of force per unit area is measure of

(A) magnetic flux density. (B) magnetic field intensity.

(C) mmf. (D) susceptibility.

Q-7 If in an iron cored coil the iron core is remove so as to make the air-cored coil, the inductance of

the coil will be

(A) more. (B) less.

(C) the same. (D) none of these.

Q-8 In a dc series motor, the torque developed is

(A) inversely proportional to armature

current.

(B) directly proportional to armature current.

(C) proportional to the square of

armature current.

(D) proportional to the square root of the

armature current.

Q-9 The most inefficient method for speed control of dc motors is

(A) voltage control. (B) field control.

(C) armature control. (D) none of above.

Q-10 The function of a starter in a dc motor is to

(A) control its speed. (B) limit the starting current to a safer value.

(C) increase its starting torque. (D) none of above.


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Q-11 Laminated yoke in the DC machine can be reduce

(A) speed regulation. (B) iron loss.

(C) temperature rise. (D) sparking on a load.

Q-12 A 4 pole generator with 16 coils has a two layer lap winding. The pole pitch is

(A) 32 (B) 16

(C) 8 (D) 4

Q-13 A DC shunt motor running at light load, what happen if the field winding is get opened?

(A) motor will stop (B) motor will burn

(C) motor will make noise (D) motor will pick up high speed

Q-14 The minimum number of windings required for producing poly phase fields is

(A) One. (B) Two.

(C) Three. (D) None of these.

Q-15 One of the characteristics of single phase motor is that it

(A) is self starting. (B) is not self starting.

(C) requires only one winding. (D) can rotate in one direction only.

Q-16 The variable loss in a dc shunt machine is

(A) iron loss. (B) shunt field loss.

(C) armature copper loss. (D) friction and windage loss.

Q-17 Reverse resistance of diode is of the

(A) m. (B) .

(C) K. (D) M.

Q-18 A triac is a

(A) unidirectional diode. (B) bidirectional thyristor.

(C) a combination of two P-N diodes. (D) none of these.

Q-19 Efficiency of a dc machine is maximum when the variable losses are equal to

(A) constant losses. (B) square of the constant losses.

(C) square root of the constant losses. (D) none of the above.

Q-20 The primary ampere-turns are counter balanced by

(A) secondary ampere-turns. (B) primary flux.

(C) increase in mutual flux. (D) increase in secondary current.

Q-21 An alternator driven by a steam turbine is known as a

(A) turbo-generator. (B) hydro-generator.

(C) steam generator. (D) none of the above.


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Q-22 In MHD generator conductor is made of

(A) aluminum. (B) copper.

(C) nichrome. (D) none of them.

Q-23 The armature reaction effect in a synchronous machine depends on

(A) load current. (B) power factor of the load.

(C) speed of the machine. (D) both (a) and (b).

Q-24 An open circuit test on a transformer is performed basically to determine

(A) copper loss. (B) iron loss.

(C) regulation. (D) leakage impedance.

Q-25 Back-to-back HVDC is used to

(A) increase the transmission capacity. (B) decrease the line losses.

(C) provide stable interconnection. (D) reduce voltage drop.

Q-26 The motor preferred for traction work is

(A) dc shunt motor. (B) dc series motor.

(C) plain squirrel cage induction

motor.

(D) synchronous motor.

Q-27 Specific energy consumption is highest in

(A) urban services. (B) suburban service.

(C) main line service. (D) equal for all types services.

Q-28 In performing the short-circuit test on a transformer

(A) high voltage side is usually short

circuited.

(B) low voltage side is usually short circuited.

(C) any side is usually short circuited. (D) none of the above.

Q-29 Which of the following methods is best for determining the voltage regulation of alternators?

(A) EMF method (B) MMF method

(C) Potier or ZPF method (D) none of the above.

Q-30 Measuring range of a voltmeter can be extended by using

(A) high shunt resistance. (B) high series resistance.

(C) low shunt resistance. (D) low series resistance.

Q-31 In two wattmeter method of measuring power in a 3-phase system one of the wattmeter read

negative implying

(A) wattmeter connection is faulty. (B) load is unbalance.

(C) power flow is in the reverse

direction.

(D) pf is less then 0.5.


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Q-32 As the load is increased on a synchronous motor, its speed

(A) decreases. (B) increases.

(C) remains constant and additional

load is supplied by shift in relative

position of the rotor with respect

to stator rotating field.

(D) remains constant for some time and then

falls abruptly.

Q-33 The sag produced in the conductor of a transmission wire depends on

(A) weight of the conductor per unit

length.

(B) tension in the conductor.

(C) length of the conductor. (D) all of the above.

Q-34 Which instrument has the lowest resistance?

(A) ammeter (B) voltmeter

(C) frequency meter (D) megger

Q-35 The source of electron beam in a CRO is

(A) electron gum. (B) grid.

(C) focusing anode. (D) vertical deflecting plates.

Q-36 An inter connector between two generating station facilitates to

(A) keep their voltage constant. (B) run them in parallel.

(C) transfer power in either direction. (D) both (b) and (c).

Q-37 A servo-motor has the drawback of

(A) commutation problem (B) low starting torque.

(C) poor reliability. (D) all of these.

Q-38 LVDT is a/an

(A) eddy current transducer. (B) inductive transducer.

(C) resistive transducer. (D) magneto-striction transducer.

Q-39 twos complement of a binary number 1010 is

(A) 0101. (B) 0001.

(C) 0110. (D) 1001.

Q-40 A microprocessor consists of(A) ALU. (B) memories.

(C) I/O devices. (D) all of the above.

Q-41 For long EHV/UHV transmission lines, we normally use

(A) SF6 circuit breaker. (B) air blast circuit breaker.


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(C) oil circuit breaker. (D) isolating swich.

Q-42 The disadvantage(s) of renewable sources of energy is/are

(A) intermittency. (B) lack of dependability.

(C) availability in low energy densities. (D) all of the above.

Q-43 ACSR means(A) Aluminum Core Standard Resistor. (B) Aluminum Conductors Steel Reinforced.

(C) All Conductors Steel Reinforced. (D) Anodised Core Steel Reinforced.

Q-44 Wien bridge oscillator is basically a

(A) Pulse generator. (B) Sine wave generator.

(C) Square wave generator. (D) triangular wave generator.

Q-45 Which of the following methods of heating is independent of supply frequency?

(A) Electric arc heating. (B) Induction heating.

(C) Electric resistance heating. (D) dielectric heating.

Q-46 A synchro is used to

(A) accelerate a rotating shaft. (B) convert an angular position of a shaft in to

an electrical signal.

(C) covert linear motion into angular

position.

(D) amplify low frequency signals.

Q-47 Which switch is used for staircase wiring?

(A) two way switch (B) one way switch

(C) multi way switch (D) none of the above

Q-48 The output of a stepper motor is in the form of

(A) linear movements. (B) angular movements.

(C) either (a) or (b). (D) none of the above

Q-49 Power factor of a synchronous motor can be varied by varying

(A) applied voltage. (B) supply frequency.

(C) excitation. (D) load.

Q-50 Kirchhoffs current law is applicable to only

(A) Closed loop in a network. (B) Electronic circuits.

(C) Junctions in a network. (D) Electric circuits.

Q-51 The most commonly used transistor circuit is

(A) common emitter. (B) common base.


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(C) common collector. (D) all of the above three equally.

Q-52 An outstanding feature of a universal motor is its

(A) Best performance at 50 Hz supply. (B) Slow speed at all loads.

(C) Excellent performance on dc

supply.

(D) Highest output kW/kg ratio.

Q-53 Which of the following materials is not a semiconductor?

(A) Silica. (B) Germanium.

(C) Selenium. (D) Gallium Arsenide.

Q-54 When a P-N junction is forward biased

(A) minority carriers remain

unaffected.

(B) holes and electrons move away from the

junction.

(C) barrier breaks down. (D) depletion region reduces.

Q-55 Lenzs law states that the direction of the induced emf hence current

(A) is determined by the rate of

current flux.

(B) is found by the right hand rule.

(C) is found by the right hand rule. (D) always opposes the cause producing it.

Q-56 Which of the following diodes is used for voltage stabilization?

(A) P-N junction. (B) Zener.

(C) Tunnel. (D) Hot carrier diode.

Q-57 Transistor is a

(A) current controlled current device. (B) current controlled voltage device.

(C) voltage controlled current device. (D) voltage controlled voltage device.

Q-58 The magnetic potential in a magnetic circuit can be measured in terms of

(A) mmf. (B) emf.

(C) henry. (D) coulomb

Q-59 The property of a material which oppose the creation of magnetic flux in it.

(A) Resistance (B) Reluctance

(C) Permeance (D) Conductance

Q-60 The output of the gate is 1 if and if all the inputs are zero. The gate is

(A) OR gate. (B) AND gate.

(C) NOR gate. (D) NAND gate.

Q-61 Long distance railways operated on

(A) 600 V DC. (B) 25KV single phase AC.


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(C) 25KV Three phase AC. (D) 11KV Three phase AC.

Q-62 The lagging effect between flux density of the material and the magnetizing force applied.

(A) Permeance (B) Eddy current

(C) Hysteresis (D) Reluctance

Q-63 The symbol Q refers to

(A) resonance quotient. (B) quality factor.

(C) power quotient. (D) qualification test.

Q-64 VL= VCin a series RLC circuit when

(A) The value of the impedance is

minimum.

(B) The power factor is zero.

(C) The current leads the total voltage

by 90o

(D) The total voltage is zero.

Q-65 Which semiconductor power device out of the following is not a current triggered device?

(A) Thyristor. (B) GTO.

(C) Triac. (D) MOSFET.

Q-66 The decimal equivalent of binary 10011 is

(A) 7. (B) 21.

(C) 17. (D) 19.

Q-67 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-68 In an RL series circuit,

(A) Current lags voltage by less than

90o

(B) Current lags voltage by 180o

(C) Current lags voltage by 90o (D) Current leads voltage by 90

o

Q-69 When a thyristor is in ON state, its gate drive be

(A) removed to save power. (B) removed or may not be removed.

(C) not removed as it will turn off the

thyristor.

(D) removed to avoid increased losses and

higher junction temperature.

Q-70 The impedance relay is used for protection of

(A) transformer. (B) bus-bar.


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(C) synchronous generator. (D) transmission line.

Q-71 Which of the following is the statement of Ohms law?

(A) Electric current is directly

proportional to both voltage and

resistance.

(B) Electric current varies directly as the voltage

and inversely as the resistance.

(C) Electrical power is directlyproportional to the resistance and

inversely as the current squared.

(D) Electrical power is directly proportional toboth voltage squared and the resistance.

Q-72 The ratio between the active power and the apparent power of a load in an ac circuit is called

(A) Quality factor (B) Power factor

(C) Power ratio (D) Power reactive

Q-73 A relay used for protection of motors against over-load is

(A) induction relay. (B) thermal relay.

(C) impedance relay. (D) mho relay.

Q-74 The commercial sources of energy are

(A) fossile fuels,water and radioactive

substances.

(B) solar,wind and biomass.

(C) wood,animal wastes and

agricultural wastes.

(D) none of the above.

Q-75 When the emitter junction is forward biased while the collector junction is reverse biased, the

transistor is at _________region.

(A) cut-off (B) saturation

(C) active (D) breakdown

Q-76 HDPE conduit is permitted to be used in which of the following locations:

(A) Areas subject to severe corrosive

factors.

(B) Hazardous classified locations.

(C) Areas with ambient temperatures

over 50 degrees C.

(D) All of the above.

Q-77 Potentiometer is a/an ____________instrument.

(A) indicating (B) comparison

(C) calibrating (D) recording

Q-78 Bundled conductors are mainly used

(A) to increase the shunt capacitance. (B) to decrease the shunt capacitance.

(C) to increase the series reactance. (D) to decrease the series reactance.

Q-79 Electrical systems that are grounded must meet which of the following requirements:

(A) Be connected to the earth in a way (B) Be connected to the earth in a manner that


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that limits the voltage caused by

line surges.

will stabilize the voltage to the earth during

normal operation.

(C) Both of the above. (D) None of above.

Q-80 The mechanical power developed by the armature of a dc motor is equal to

(A) armature current multiplied by

back emf.

(B) power input minus losses.

(C) power output multiplied by

efficiency.

(D) power output plus iron losses.

Q-81 Which of the following instrument is most accurate?

(A) PMMC. (B) Moving Iron.

(C) Thermocouple. (D) Induction type.

Q-82 The modern steam turbines are

(A) reaction turbines. (B) impulse turbines.

(C) impulse reaction turbines. (D) none of the above.

Q-83 The speed of a dc motor can be controlled by varying

(A) Its flux per pole. (B) resistance of armature circuit.

(C) applied voltage. (D) all of the above.

Q-84 A transformer transforms

(A) frequency. (B) voltage.

(C) current. (D) voltage and current.

Q-85 In PMMC instruments the scale is

(A) non-linear. (B) logarithmic.

(C) exponential. (D) uniformally divided.

Q-86 For arc heating, the electrodes used are made of

(A) copper. (B) graphite.

(C) tungsten. (D) aluminium.

Q-87 The primary and secondary windings of an ordinary two winding transformer always have

(A) same number of turns. (B) same size of copper wire.

(C) a common magnetic circuit. (D) separate magnetic circuits.

Q-88 Which of the following connections is best suited for 3-phase, 4-wire service?

(A) Delta-Delta (B) Star-Star(C) Delta-Star (D) Star-Delta

Q-89 A solar cell is the same as a

(A) photo conductive cell. (B) photo voltaic cell.

(C) photo emissive cell. (D) photo tube.

Q-90 Load curve helps in deciding the

(A) total installed capacity of the plant. (B) size of the generating units.


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(C) operating schedule of the

generating units.

(D) all of the above.

Q-91 Lumens per watt is the unit of

(A) luminous efficiency. (B) brightness.

(C) luminous intensity. (D) illumination.

Q-92 Spinning reserve is

(A) the reserve generating capacity

which is available for service but

not in operation.

(B) the reserve generating capacity which is

connected to the bus and ready to take load.

(C) the reserve generating capacity

which is in operation but not in

service.

(D) none of the above.

Q-93 The permissible variation of frequency in power system is

(A) 2%. (B) 3%.

(C) 5%. (D) 10%.

Q-94 During regenerative braking(A) the motors are disconnected from

the supply.

(B) the motors are reverse connected to the

supply.

(C) the motors are operated as

generators.

(D) the motors are made to come to stand-still.

Q-95 Breakdown of cable insulation may occur due to

(A) thermal instability. (B) puncture.

(C) tracking. (D) any of the above.

Q-96 In distribution system for power factor improvement, the power factor correction devices are

installed

(A) at the sending end. (B) near the earthing point.

(C) at the load end. (D) any where in the circuit.

Q-97 The illumination level in houses is in the range of

(A) 25-50 lux. (B) 100-200 lux.

(C) 300-500 lux. (D) 700 lux.

Q-98 When two or more motors are used for traction service, the method of speed control used will be

(A) rheostatic control. (B) series-parallel control.

(C) field control. (D) motor generator control.

Q-99 According to De Margan's second theorem

(A) A NAND gate is always

complementary to an AND gate.

(B) An AND gate is equivalent to a bubbled

NAND gate.

(C) A NAND gate is equivalent to a

bubbled AND gate.

(D) A NAND gate is equivalent to a bubbled OR

gate.

Q-100 A 555 timer can be used as


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(A) an astable multivibrator only. (B) a monostable multivibrator only.

(C) a frequency divider only. (D) all of above.

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