ENGINEERING > ELECTRICAL
1) To prepare a P type semiconducting material the impurities lo be added to silicon are
A) Boron, GalliumB) Arsenic, Antimony
C) Gallium. PhosphorousD) Gallium, Arsenic
View AnswerDiscuss on this        
Answer : Boron, Gallium


2) In Bipolar Junction transistors, the type of configuration which will give both voltage gain and current gain is
A) CCB) CB
C) CED) None
View AnswerDiscuss on this        
Answer : CE


3) With the positive probe on an NPN base, an ohmmeter reading between the other transistor terminals should be
A) OpenB) Infinite
C) Low resistanceD) High resistance
View AnswerDiscuss on this        
Answer : Low resistance


4) To operate properly, a transistor"s base-emitter junction must be forward biased with reverse bias applied to which junction ?
A) Collector-emitterB) Base-collector
C) Base-emitterD) Collector-base
View AnswerDiscuss on this        
Answer : Base-collector


5) Silicon has a preference in 1C technology because
A) it is an indirect semiconductorB) it is a covalent semiconductor
C) it is an elemental semiconductorD) of the availability of nature oxide SiO
View AnswerDiscuss on this        
Answer : of the availability of nature oxide SiO


6) An amplifier has a gain of 10,000 expressed in decibels the gain is
A) 10B) 40
C) 80D) 100
View AnswerDiscuss on this        
Answer : 80


7) The electric drives posses the following drawback
A) not available with various ratingB) requires a continuous power supply
C) requires hazardous fuel requirementD) not adoptable to various environments
View AnswerDiscuss on this        
Answer : requires a continuous power supply


8) An arc blow is a welding defect that is countered with the help of carrying
A) the arc welding using AC supplyB) the thermit welding
C) the arc welding using DC supplyD) the resistance welding
View AnswerDiscuss on this        
Answer : the arc welding using DC supply


9) During the resistance welding, ibe heat produced at the joint is proportional to
A) I2RB) Voltage
C) CurrentD) Volt-Ampere
View AnswerDiscuss on this        
Answer : I2R


10) An electric heater draws 3-5 A from a 110 V source. The resistance of the heating element is approximately
A) 385 ?B) 38.5 ?
C) 3.1 ?D) 31 ?
View AnswerDiscuss on this        
Answer : 31 ?


11) The unit of luminous flux is
A) steradianB) candela
C) lumenD) lux
View AnswerDiscuss on this        
Answer : candela


12) A 200 V lamp takes a current of 1 A, it produces a total flux of 2,860 lumens. The efficiency of the lamp is
A) 99 lumens/WB) 8.9 lumens/W
C) 10.9 lumens/WD) 14.3 lumens/W
View AnswerDiscuss on this        
Answer : 14.3 lumens/W


13) Humans are more vulnerable to electric shock current al
A) 40 HzB) 45 Hz
C) 48 HzD) 50 Hz
View AnswerDiscuss on this        
Answer : 50 Hz


14) The acceptable value of grounding resistance for domestic applications is
A) 0.5?B) 1?
C) 1.5?D) 2?
View AnswerDiscuss on this        
Answer : 1?


15) The minimum area of cross-section of a three and half core cable should be
A) 30 cm7B) 40 cm2
C) 50 cm2D) 60 cm2
View AnswerDiscuss on this        
Answer : 50 cm2


16) Ine aluminium conductor of size is used for a subcircuit in domestic wiring
A) 1/1.2 mmB) 1/1.4 mm
C) 1/1.8 mmD) 1/2.24 mm
View AnswerDiscuss on this        
Answer : 1/1.4 mm


17) For cleat wiring and 250 volts supply, the cables will be placed ___ apart centre to centre for single core cables
A) 2.5 cmB) 3 cm
C) 4 cmD) 4.5 cm
View AnswerDiscuss on this        
Answer : 2.5 cm


18) In batton wiring the cables are carried on seasoned teak wood perfectly straight and well varnished teak wood batton of thickness not less than
A) 1 cmB) 2 cm
C) 3 cmD) 4 cm
View AnswerDiscuss on this        
Answer : 1 cm


19) The permissible voltage drop from supply terminal to any point on the wiring system should not exceed
A) 4% + 1 voltB) 3% + 1 volt
C) 2% + 1 voltD) 1% + 1 volt
View AnswerDiscuss on this        
Answer : 4% + 1 volt


20) For painful shock, what is the range of electric shock current at 50 Hz ?
A) 0-1 mAB) 0-3 mA
C) 3-5 mAD) 5-10 mA
View AnswerDiscuss on this        
Answer : 3-5 mA


21) In dc operation of fluorescent lube, the life of the tube
A) increases by about 80% as that with ac operationB) decreases by about 80% as that with ac operation
C) remain sameD) may increase or decrease
View AnswerDiscuss on this        
Answer : decreases by about 80% as that with ac operation


22) What is the maximum number of point of light, fan and socket-outlets that can be connected in one sub-circuit ?
A) FourB) Six
C) TenD) Twelve
View AnswerDiscuss on this        
Answer : Ten


23) An alternator is supplying a load of 300 kW at a power factor of 0-6 lagging. If the power factor is raised to unity, how many more kW can alternator supply ?
A) 100 kWB) 150 kW
C) 200 kWD) 300 kW
View AnswerDiscuss on this        
Answer : 200 kW


24) If span length is doubled with no change in other factors, the sag of the line will become
A) 0.5 timeB) 2 times
C) 4 timesD) 8 times
View AnswerDiscuss on this        
Answer : 4 times


25) Which of the following fault is coming under symmetrical fault?
A) LG faultB) LL fault
C) LLG faultD) LLLG fault
View AnswerDiscuss on this        
Answer : LLLG fault


26) A circuit breaker is rated as follows : 1500 A, 33 KV, 3 sec, 3-phase oil circuit breaker. Determine the making current
A) 1.5 KAB) 35 KA
C) 89 KAD) 110 KA
View AnswerDiscuss on this        
Answer : 89 KA


27) If the power factor is high, then the consumer maximum RVA demand
A) increasesB) decreases
C) remains constantD) becomes zero
View AnswerDiscuss on this        
Answer : increases


28) Base load of a power station stands for
A) 2-4 hours/dayB) 4-8 hours/day
C) 8-12 hours/dayD) 12-24 hours/day
View AnswerDiscuss on this        
Answer : 8-12 hours/day


29) The per phase DC armature resistance of an alternator is 0.5? The effective AC armature resistance would be about
A) 0.25 ?B) 0.5 ?
C) 0.75 ?D) 1 ?
View AnswerDiscuss on this        
Answer : 0.75 ?


30) The reactive power generated by a synchronous alternator can be controlled by
A) changing the prime move inputB) changing the alternator speed
C) changing the field excitationD) changing the terminal voltage
View AnswerDiscuss on this        
Answer : changing the field excitation


31) A 10 pole 25 Hz alternator is directly coupled to and is driven by 60 Hz synchronous motor then the number of poles in a synchronous motor are
A) 48 polesB) 12 poles
C) 24 polesD) None of the above
View AnswerDiscuss on this        
Answer : 24 poles


32) A salient-pole synchronous motor is operating at 1/4- full-load. If its field current is suddenly switched off. it would
A) stop runningB) continue to run at synchronous speed
C) run at sub-synchronous speedD) run at super-synchronous speed
View AnswerDiscuss on this        
Answer : run at sub-synchronous speed


33) Which of the following motor is non-self starting ?
A) Squirrel cage induction motorB) Slip ring induction motor
C) Synchronous motorD) DC series motor
View AnswerDiscuss on this        
Answer : Synchronous motor


34) Synchronous impedance method of finding voltage regulation of an alternator is called pessimistic method because
A) it is simplest to perform and computeB) it gives regulation value higher than is actually found by direct loading
C) armature reaction is wholly magnetisingD) it gives regulation value lower than is actually found by direct loading
View AnswerDiscuss on this        
Answer : it gives regulation value higher than is actually found by direct loading


35) Each of the following statements regarding a shaded pole motor is true except
A) its direction of rotation is from unshaded to shaded portion of polesB) it has very poor efficiency
C) it has very poor power factorD) it has high starting torque
View AnswerDiscuss on this        
Answer : it has high starting torque


36) Locked rotor current of a shaded pole motor is
A) equal to full load currentB) less than full load current
C) slightly more than full load currentD) several times the full load current
View AnswerDiscuss on this        
Answer : equal to full load current


37) Which of the following motors is preferred for tape-recorders?
A) Shaded pole motorB) Hysteresis motor
C) Two valve capacitor motorD) Universal motor
View AnswerDiscuss on this        
Answer : Two valve capacitor motor


38) The motor used on small lathes is usually
A) universal motorB) D.C. shunt motor
C) single phase capacitor run motorD) 3-phase synchronous motor
View AnswerDiscuss on this        
Answer : D.C. shunt motor


39) Which of the following motors is used in mixies ?
A) Repulsion motorB) Reluctance motor
C) Hysteresis motorD) Universal motor
View AnswerDiscuss on this        
Answer : Universal motor


40) The purpose of starting winding in a single-phase induction motor is to
A) Reduce lossesB) Limit temperature rise of the machine
C) Produce rotating flux in conjunction with main windingD) Increase losses
View AnswerDiscuss on this        
Answer : Produce rotating flux in conjunction with main winding


41) The Ta Vs la graph of a dc series motor is a
A) parabola from no load to over loadB) straight line throughout
C) parabola throughoutD) parabola up to frill load and a straight line at over load
View AnswerDiscuss on this        
Answer : parabola up to frill load and a straight line at over load


42) As the load is increased, the speed of a dc shunt motor
A) increases proportionatelyB) remains constant
C) increases slightlyD) reduces slightly
View AnswerDiscuss on this        
Answer : remains constant


43) A short shunt compound generator supplies a load current of 100 A at 250 V. The generator has the following winding resistances: shunt field = 130 ?. armature = 0.1? and scries field = 0.1 ?. Find the emf generated if the brush drop is 1 V per brush
A) 262.0 voltB) 262.2 volt
C) 272.0 voltD) 272.2 volt
View AnswerDiscuss on this        
Answer : 272.2 volt


44) If stator voltage of a squirrel cage induction motor is reduced to 50 per cent of its rated value, torque developed is reduced by how many percentage of its full load value ?
A) 50%B) 25%
C) 75%D) 57.7%
View AnswerDiscuss on this        
Answer : 25%


45) An eight pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 rpm by a prime mover in the opposite direction of revolving magnetic field. The frequency of rotor current is
A) 60 HzB) 120 Hz
C) 180 HzD) 200 Hz
View AnswerDiscuss on this        
Answer : 180 Hz


46) Which of the following Braking is not suitable for motors ?
A) Dynamic brakingB) Plugging
C) Regenerative brakingD) Friction braking
View AnswerDiscuss on this        
Answer : Friction braking


47) The no load primary current I0. is about ____ of full load primary current of a transformer
A) 3-5%B) 15-30%
C) 30-40%D) Above 40%
View AnswerDiscuss on this        
Answer : 3-5%


48) Leakage flux in a transformer occurs because
A) iron core has high permeabilityB) air is not a good magnetic insulator
C) applied voltage is sinusoidalD) transformer is not an efficient device
View AnswerDiscuss on this        
Answer : air is not a good magnetic insulator


49) The primary and secondary windings of a transformer arc wound on (he lop of each other in order to reduce
A) iron lossesB) copper losses
C) leakage reactanceD) winding resistance
View AnswerDiscuss on this        
Answer : leakage reactance


50) The no load input power to a transformer is practically equal to ____ loss in the transformer
A) IronB) Copper
C) Eddy currentD) Windage
View AnswerDiscuss on this        
Answer : Iron


51) A Lissajous pattern on an oscilloscope has 5 horizontal tangencics and 2 vertical tan-gencies. The frequency of the horizontal input is 100 Hz. The frequency of the vertical input will be
A) 400 HzB) 2500 Hz
C) 4000 HzD) 5000 Hz
View AnswerDiscuss on this        
Answer : 2500 Hz


52) A dc voltmeter has a sensitivity of 1000 ?/volt When it measures half full scale in 100 V range, the current through the voltmeter will
A) 100 mAB) 50 mA
C) 1 mAD) 0.5 mA
View AnswerDiscuss on this        
Answer : 1 mA


53) A 150 V moving iron voltmeter of accuracy class 10 reads 75 V when used in a circuit under standard conditions. The maximum possible percentage error in the reading is
A) 0.5B) 1.0
C) 2.0D) 4.0
View AnswerDiscuss on this        
Answer : 2.0


54) If a dynamometer type wattmeter is connected in an ac circuit, the power indicated by the wattmeter will be
A) Volt ampere productB) Average power
C) Peak powerD) Instantaneous power
View AnswerDiscuss on this        
Answer : Average power


55) Modern electronic multimeters measure resistance by
A) using a bridge circuitB) using an electronic bridge compensator for nulling
C) forcing a constant current and measuring the voltage across the unknown resistanceD) using an electrical bridge circuit
View AnswerDiscuss on this        
Answer : using an electronic bridge compensator for nulling


56) Which instrument is used to measure the high resistance ?
A) Kelvin"s Double bridgeB) Wheatstone bridge
C) Carey-Foster bridgeD) Megger
View AnswerDiscuss on this        
Answer : Megger


57) Creeping in a single phase induction type energy meter may be due to
A) over compensation for frictionB) over voltage
C) vibrationsD) All of these
View AnswerDiscuss on this        
Answer : All of these


58) A CRO screen has ten divisions on the horizontal scale. If a voltage signal 5 sin(314t+45) is examined with a line base setting of 5 msec/div, the number of cycle of signal displayed on (he screen will be
A) 0.5 cycleB) 2.5 cycles
C) 5 cyclesD) 10 cycles
View AnswerDiscuss on this        
Answer : 2.5 cycles


59) The errors in current transformers can be reduced by designing them with
A) high permeability and low loss core materials, avoiding any joints in the core and also keeping the flux density to a low valueB) using primary and secondary windings as close to each other as possible
C) using large cross-section for both primary and secondary winding conductorsD) All of these
View AnswerDiscuss on this        
Answer : All of these


60) In a parallel RLC circuit if the lower cut-off frequency is 2400 Hz and the upper cut-off frequency is 2800 Hz what is the bandwidth ?
A) 400 HzB) 2400 Hz
C) 2800 HzD) 5200 Hz
View AnswerDiscuss on this        
Answer : 400 Hz


61) In a three phase system, the volt ampere rating is given by
A) 3 VLILB) ?3 VLIL
C) VLILD) Vph Iph
View AnswerDiscuss on this        
Answer : ?3 VLIL


62) Three wattmeter method of power measure ment can be used to measure power in
A) Balanced circuitsB) Unbalanced circuits
C) Both balanced and unbalanced circuitsD) None of the above
View AnswerDiscuss on this        
Answer : Unbalanced circuits


63) When a series RL circuit is connected to a voltage source V at t = 0, the current passing through the inductor L at t = 0+ is
A) V/RB) infinite
C) zeroD) V/L
View AnswerDiscuss on this        
Answer : zero


64) An RLC series circuit has R=10?, L= 2 H. What value of capacitance will make the circuit critically damped ?
A) 0.02 FB) 0.08 F
C) 0.2 FD) 0.4 F
View AnswerDiscuss on this        
Answer : 0.08 F


65) If in an RLC scries circuit, the frequency is below ihc resonant frequency, then
A) Xc - XLB) Xc < XL
C) XC>XLD) None of the above
View AnswerDiscuss on this        
Answer : XC>XL


66) To realise the full rated power of the lamps they are to be connected in
A) series onlyB) parallel only
C) series-parallelD) series or parallel
View AnswerDiscuss on this        
Answer : parallel only


67) In a pure inductive circuit if the supply frequency is reduced to 1/2, the current will
A) be reduced by halfB) be doubled
C) be four times as highD) be reduced to one fourth 133. There are 3 lamps 40 W, 100 W and 60 W
View AnswerDiscuss on this        
Answer : be doubled


68) One sine wave has a period of 2 ms. another has a period of 5 ms. and other has a period of 10 ms. Which sine wave is changing at a faster rate ?
A) Sine wave with period 2 msB) Sine wave with period of 5 ms
C) All are at the same rateD) Sine wave with period of 10 msec
View AnswerDiscuss on this        
Answer : Sine wave with period 2 ms


69) A bar of iron 1 cm2 in cross-section has 10-4wb of magnetic flux in it. If ?r=2000 what is the magnetic field intensity in the bar?
A) 398x10-4 AT/mB) 398 AT/m
C) 796x103AT/mD) 398xl04 AT/m
View AnswerDiscuss on this        
Answer : 398 AT/m


70) A current of 2 A passes through a coil of 350 turn wound on a ring of mean diameter 12 cm. The flux density established in the ring is l.4 wb/m2. Find the value of relative permeability of iron
A) 191B) 600
C) 1200D) 210 X 103
View AnswerDiscuss on this        
Answer : 600


71) The area of the hysteresis loop will be least for one of the following materials. It is
A) wrought ironB) hard steel
C) silicon steelD) soft iron
View AnswerDiscuss on this        
Answer : silicon steel


72) The magnitude of AT required to establish a given value of flux in the airgap will be much greater than that required for iron part of a magnetic circuit, because
A) air is a gasB) air is a good conductor of magnetic flux
C) air has the lowest relative permeabilityD) iron has the lowest permeability
View AnswerDiscuss on this        
Answer : air has the lowest relative permeability


73) If the co-efficient of coupling between two coils is increased, mutual inductance between the coils
A) is decreasedB) is increased
C) remains unchangedD) changes depends on current only
View AnswerDiscuss on this        
Answer : is increased


74) The unit for permeability is
A) Wb/AtxmB) At/m
C) At/WbD) Wb
View AnswerDiscuss on this        
Answer : Wb/Atxm


75) When the current through the coil of an electromagnet reverses, the
A) direction of the magnetic field reversesB) direction of the magnetic field remains unchanged
C) magnetic field expandsD) magnetic field collapses
View AnswerDiscuss on this        
Answer : direction of the magnetic field reverses


76) If the number of turns of a coil is increased, its inductance
A) remains the sameB) is increased
C) is decreasedD) None of the above
View AnswerDiscuss on this        
Answer : is increased


77) Mutual inductance between two coils is 4 H. If current in one coil changes at the rate of 2 A/sec, then emf induced in the other coil is
A) 8 VB) 2 V
C) 0.5 VD) 50 V
View AnswerDiscuss on this        
Answer : 8 V


78) The internal resistance of a voltage source is 10? and has 10 volts at its terminals. Find the maximum power that can be transferred to the load
A) 0.25 WB) 25 W
C) 2.5 WD) 5W
View AnswerDiscuss on this        
Answer : 2.5 W


79) A node in a circuit is defined as a
A) closed pathB) junction of two or more elements
C) group of interconnected elementsD) open terminal of an element
View AnswerDiscuss on this        
Answer : junction of two or more elements


80) Thevenin"s theorem cannot be applied to
A) active circuitB) linear circuit
C) nonlinear circuitD) passive circuit
View AnswerDiscuss on this        
Answer : active circuit


81) The superposition theorem is used when the circuit contains
A) a single voltage sourceB) a number of voltage sources
C) passive elements onlyD) active elements only
View AnswerDiscuss on this        
Answer : a number of voltage sources


82) If 750 ?A is flowing through 11 k? of resistance, what is the voltage drop across the resistor ?
A) 8.25 VB) 82.5 V
C) 14.6 VD) 146 V
View AnswerDiscuss on this        
Answer : 8.25 V


83) An active element in a circuit is one which
A) supplies energyB) receives energy
C) dissipates energyD) both receives and supplies energy
View AnswerDiscuss on this        
Answer : supplies energy


84) A linear circuit is one whose parameters
A) change with change in currentB) change with change in voltage
C) do not change with voltage and currentD) None of the above
View AnswerDiscuss on this        
Answer : do not change with voltage and current


85) What is the Power consumed by the resistor of 20? connected across 100 V source?
A) 500 WB) 50 W
C) 100 WD) 300 W
View AnswerDiscuss on this        
Answer : 500 W


86) How much energy is stored by a 100 mH inductance when a current of 1 A is flowing through it ?
A) 0.5 JB) 0.05 J
C) 0.005 JD) 5.0 J
View AnswerDiscuss on this        
Answer : 0.05 J


87) The rate of change of current in a 4 H inductor is 2 Amps/sec. Find the voltage across inductor.
A) 8 VB) 0.8 V
C) 2 VD) 16 V
View AnswerDiscuss on this        
Answer : 2 V


88) Electrical resistivity p is
A) Low for copper and high for alloyB) High for copper and low for alloy
C) Low for copper as well as for alloyD) High for copper as well as for alloy
View AnswerDiscuss on this        
Answer : High for copper and low for alloy


89) A primary cell has an c.m.f of 1.5 V. When short circuited, it gives a current of 3 internal resistance of cell is
A) 4.5 ?B) 2 ?
C) 0.2 ?D) 0.5 ?
View AnswerDiscuss on this        
Answer : 0.5 ?


90) A resistor is connected across a 50 V source. The current in the resistor if the colour code is red, orange, orange, silver is
A) 2 mAB) 2.2 mA
C) 214 mAD) 21.4 mA
View AnswerDiscuss on this        
Answer : 2.2 mA


91) If two capacitances C, and C2 are connected in parallel then the equivalent capacitance is given by
A) C1C2B) C1/C2
C) C1C2/C1 + C2D) C1 + C2
View AnswerDiscuss on this        
Answer : C1C2/C1 + C2


92) The slenderness ration of a compression member is
A) Effective length / Least radius of gyrationB) Actual length / Moment of interia
C) Moment of inertia / Actual lengthD) Actual length / Radius of gyration
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : Effective length / Least radius of gyration


93) Zeroth Law of thermodynamics forms the basis of ________ measurement
A) PressureB) Temperature
C) WorkD) Momentum
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : Temperature


94) A triac is a
A) Two terminal bi-directional switchB) Three terminal bi-directional switch
C) Two terminal uni-directional switchD) Three terminal uni-directional switch
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : Three terminal bi-directional switch


95) Which device changes the alternating e.m.f. generated by the D.C. Generator in its armature coil to D.C
A) Slip ringB) Rectifier
C) CommutatorD) None of these
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : Commutator


96) With which of the following, the intrinsic sesmi conductor Silicon be doped in order to obtain p-type semi-conductor
A) BoronB) Phosphorus
C) GalliumD) None of these
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : Boron


97) The property of a matertial by which it can be rolled into sheets is called
A) ElasticityB) Plasticity
C) DuctilityD) Malleability
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : Malleability


98) A conductor of axial length 30 cms carries a current of 100 A and lies at right angle to a magnetic field of strength 0.4 tesla. What is the force exerted on it
A) 10 NB) 12 N
C) 1.2 ND) 0
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : 12 N


99) When an object is cut by a section plane, parallel to H.P. and perpendicular to V.P., then the sectional view of the object is obtained in
A) Top viewB) Front view
C) Left side viewD) Right side view
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : Top view


100) A capacitor stores 1 coulomb at 10 volts. Its capacitance is (f=farad)
A) 1 fB) 10 f
C) 0.1 fD) 0.01 f
View AnswerDiscuss on this        RRB JE Green 2014 QP Answer key
Answer : 0.1 f