WBPSC JE 2018: All papers, Junior Engineer (Electrical) 2017
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J E Guee) IEEl17
DO NOT OPEN THIS BOOKLET UNIIL YOU ARE ASKED TO DO SO.
201t TEST B{x)xI,ET SEXIET
TEST BOOKLET
ELECTRICAL ENGINEERING
Time allowed : 2 hours
Full marts : 2fi)
Answer alt the questions.
Questions are of equal value.
Serial No
0160{? RoA No.
Signature ol the Candifule :
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1. This booklet consists of 16 pages including this front page, 100 questions. Verif, the Page Nos. and
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IEEl17 B-2
1. One ofthe control sprhgs ofa permanent magnet 6. When the pointer of an indicating instrument is
moving coil ammeterisbroken.Ifconnected in a circuit, in the final deflection position, at that time
the meter would read (A) deflection torque is zero.
(A) zero (B) contolling torque is zero.
(B) half the correct value of the current (C) damping torque is zero.
(C) twice the conect value of the current (D) both deflecting and controlling torque are
(D) an indefinite figure zeto,
2. In squirrel-cage induction motors, the rotor slots
are usually given slight skew in order to 7. Two holes in the disc of energy meter are drilled
(A) reduce windage losses. at opposite sides of the spindle to
(B) reduce eddy currents. (A) improve its ventilation
(C) to eliminatemagnetic locking between stator (B) eleminate creeping at no load
and rotor and to reduce magnetic helm. (C) increase its deflecting torque
(D) to reduce accumulation ofdirt and dust. (D) increase its braking torque
3. In case the air gap in an induction motor is E. The electrical power to a megger is provided by
increased, (A) battery
(A) the magnetisi-ng current of the rotor will @) permanent magnet DC generator
decrease.
(C) AC generator
(B) the power factor will decrease.
(D) None of the above
(C) the speed of motor will increase.
(D) the windage losses will increase.
9. The disc of al instrument using eddy current
4. "The mass of an ion liberated at an electrode is damping should be of
direcdy proportional to the quantity ofetectricity"- the (A) conducting and magaetic material
above statement is associated with
(B) non-conducting and magnetic material
(A) Newton's law
(C) conducting and non-magnetic material
(B) Faraday's law of ele{tromagnetic
(D) non-conducting and non-magnetic meterial
(C) Faraday's law of electrolysis
(D) Gauss's law
10. In a 3-phase power measurementbytwo watEneter
5. In a lead-acid baftery the energy is stored in the method, both the wattrneters had identical readings. The
forrn of power factor of the load was
(A) charged ions (A) Uniry
(B) chemical energy (B) 0.8 lagging
(C) electrostatic energy (C) 0.8 leading
(D) electromagnetic energy (D) Z.erc
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B-3 IEEll7
11. For very sensitive and wide speed control, the 16. Of the voltage and current in an AC circuit are
preferable control method is given by v = 200 sin(ot + 30) and , = l0 sin(cot - 60)
(A) armatule control then the pf of the circuit is
l:
(B) Ward-Ironard control (A) 11
(C) multiple voltage control 2
I
(D) field control ts),
(c) 0
12. If the load current of transformer decreases, then I
(D)
the power factor E
(A) will also decrease
@) will also increase
(C) will remain unchanged
17. In the circuit shown in the frgure-3, the current
(D) None ofthe above
through resistance R1 is
2A
ror 3o
13. The most suitable location for the power factor
improvement device is ,r, io n =jo
(A) near the electrical appliance which is A
responsible for the poor power facor. (C)
,A
@) at the receiving end in case of transmission 2A
lines. ,r, io frgure-3
(C) at the sending end of the transmission lines.
@) Bodr (A) and (B)
18. Which type of insulators is used on l32kV
14. Which tariff is most ideal for the consumer? transmission lines?
(A) Two part tariff (A) Pin type
(B) thre€ part taritr (B) Disc type
(C) Bottr (A) and (B) (C) Shackle type
(D) None of the above @) Pin and Shackle type
15. A 125 km long transmission line is loaded at
l10kV. If the loss of the line in 20 MW and the load is 19. which of the following dishibution system is
175 MVA the resistance of the line is more reliable?
(A) 7'9 CUphase (A) Radial system
@) 4'56 O/phase @) Tree system
(C) 13'68 CUphase (C) Ring main system
@) 45'6 fUphase @) All are equally reliable
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IEEl17 R-4
m. If two 3fi) V firll-scale voltmeters V, and V2 Z. The ratio of making to breaking capacity for an
having sensitivity of l00kfUV and l50k(UV are extra high voltage cbcuit breaker is
connected to measure 500 V, as shown in fig-2, then (A) more than 1
(A) V1 and V2 will read 250 V (B) equal to 1
each. (C) less than 1
@) V1 will read 200V and V2 (D) None of the above
will read 300V.
500v
(C) V1 will read 300Vand V2
will read 200 V. I
(D) Vl and V2will read 0 each. I 25, What is the major cause of the failure of the
circuit beaker?
frg-2
(A) Trip circuit open
@) Trip latch defective
(C) Spring defective
21. A high ftequency as signal is applied to a PMMC (D) All of the above
instrument. If the nns value of the ac signal is 2V, then
the reading of the insrument will be
(A) zero
(B) 2v 2,5. To determine the polarity of the voltage drop
across a resistor, it is necessary to know
(q {2v
(A) the value of curent tkough the resistor.
(D) 4!2v
(B) the direction ofcurrent through the rcsistor.
(C) the value of resistor.
(D) the e.m.f in the circuit.
22. In thecircuitshown in the frgure-I, if the ammet€r
indicates lA, and the volmeter having an intemal
resistance of lkf,) indicated 100V, then the value of
R would be 27. Which type of earthing is used by transmission
lines?
(A) lll.I O IA
(A) Plate earthing
(B) 105.2 O
(B) Rod earthing
(c) 100 o R ll()
(C) Strip earthing
@) 90.9 O (D) All of the above
figure-1
28. If P is the power of a star con-oected system, then
Zl. When does the arc intemrption in oil circuit what will be the power of an equivalent delta connected
breaker take place? system?
(A) Contact apart (A) P
(B) Voltage becomes zelo (B) 2P
(C) Current goes through zero (c) P/3
(D) Curent is at iB peak (D) 3P
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B-5 IEEl17
29. Ilput resistance of a common emitter transistor 34. Why is single core cables should have armour
of the order of made of?
(A) I IVIC) (A) Non-magnetic and non-conducting malerial
(B) I kct (B) Non-magnetic material
(c) 0.010 (C) Non-magnetic but conducting marcrial
(D) 0.0mlo @) Magnetic and conducting material
30. The electrostatic sEess in underground cable is 35. Which of the following theorems applicable for
(A) same at the conductor and the sheath. both linear and non-linear circuits?
@) minimum at the conductor and maximum at (A) Superposition theorem
the sheath. (B) Thevenin's theorem
(C) maximum at the conductor surface and (C) Norton's theorem
minimum at the sheath.
(D) None ofthe above
@) zero at the conductor as well as sheath.
36. In a series RLC circuit that is operating above the
31. Field effect transistor has
resonant frequency, the current
(A) large input impedance
(A) lags the applied voltage.
(B) large output impedance
(B) leads the applied voltage.
(C) large power gain
(C) in phase with the applied voltage.
@) small voltage gain (D) is zero.
32. A parallel plate capacitor has capacitance of
l0 pF. If the linear dimensions of the plates are doubled 37. Themaximum safe temperatureof paperinsulated
and the s€paration between them is also doubled, has the cables is about
value of the capacitance would be (A) 60.C
(A) l0 pF (B) 95'C
@) 20 ttF (c) 135"c
(C) 5 rlF (D) 165"C
(D) 40 FF
3t. The isolators are used in the transmission lines
33. At NTP the breakdown strength of air is are capable of breaking
(A) 30 kV-rmVcm (A) fault current
@) 30 kv-peaUcm (B) no current
(C) zl.0 kv-peaUcm (C) charging current
@) 60 kV-peaUcm @) load current
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TEEl17 B-6
39. What will happen if the current coil and potential 44. Two capacitance Cr= 150+ 2'4 pF and
coil of dynamometer type watnneter is interchanged? Cz= l2O + 1 5 pF. What is the limiting error of the
(A) Potential coil will get damaged. resultant capacitance C?
(B) Current coil will get damaged. (A) 0 9 rrF
(C) Both current coil and potential coil will get (B) 1'9 pF
damaged. (C) 3'9 ttF
(D) Meter will read as it is. (D) 4'8 rlF
rl0. Which among these fuse is very fast in operation?
(A) Semiconductor fuse 45. For symmetrical waveform average value ofone
full cycle is
(B) High rupturing capacity type fuse
(A) 1
(C) Cartridge type fuse
(B) 1.11
(D) Kitkat type fuse
(c) 2.22
(D) 0
41. In a permanent magnet moving coil instrument,
the deflecting torque is
(A) directly proportional to both number of tums tl6. Which of the following essential features is
and flux density. possessed by an indicating instrument?
(B) direcdy proportional o rhe number of turns (A) Deflecting device
andinversely proportionalto the flux density.
@) Controlling device
(C) inversely proportional to the numberofturns
(C) Damping device
and directly proportional to the flux density.
(D) All of the above
(D) inversely proportional to both number of
rurns and flux density.
47, What quantity of charge must be delivered by a
42. In a series RL circuit, voltage across resistor and battery wift a potential difference of 110 V to do 660 J
inductor are 3 V and 4 V respectively, then what is the of work?
applied voltage? (A) 0'6 C
(A) 7v (B) 6c
(B) sv (c) 60 c
(c) 4v (D) 600c
(D) 3v
43. A spring controlled movilg iron voltmeter with .lE. A 0-25 Amp ammeter has guaranieed accuracy
full scale deflection of 150 V draws a cunent of 2 mA. of I % of firll scale reading, the current measured by this
What will be the meter reading if it draws a current of ammeter is 10 Amp. The limi ting error in percentage for
1mA? this hstrument is
(A) 2s.s v (A) 2.59o
(B) 27.sY (B) O.25?o
(c) 3s's v (c) o.o2s%
(D) 37.s v @) o.N2s%
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B-7 .IEEIIT
49. A thyrite type lightning arrestor 54. In a PMMC instrument, the torque weight ratio is
(A) blocks the surge voltage appearing in a line (A) hieh
(B) absorbs the surge voltage appearing in a line (B) low
(C) offers a low resistance path to the surge (C) zero
appearing in the line
(D) infrnity
(D) retums the surge back to the source
50. Where the voltages are high and cunent to be
intenupted is low, the breaker prefened is
55. The advantage of neutral earthing is
(A) ai-r blast circuit breaker (A) safety of personnel
(B) oil circuit breaker
(B) reduction of earth fault currenr
(C) vacuum circuit breaker
(C) elimination of arcing $ound
(D) None of the above
(D) None of the above
51. A 5 kVA transformer has a turn ratio of
Nr/N2 = 10. The impedance of the primary winding is
3+j5 ohms while that of secondary winding is 56. Two charges of equal magnitude are separated
0'5 + j 0.8 ohms. The impedance of the transformer
by some distance. If the charges are increased by 107o,
when referred to the primary will be
to get the same force between them, their separation
(A) 3.5 + j 5.8 ohms must be
(B) 8'0 + j 13'0 ohms (A) increased by 217o
(C) 53'0 + j 85 ohms (B) increased by l07o
(C) decreased by l0%
(D) 3'05 + j 5'08 ohms (D) None of the above
52. Directional induction type over current relay is
used for protection of
(A) Long transmission line 57. A DC motor is running with a certain load. The
(B) Large power transformer effect of adding an external resistance in the shunt field
circuit is
(C) Ring main distribution line (A) to increase the motor speed.
(D) Radial distribution line (B) to reduce the motor speed.
(C) to reduce the armature current motor.
53. The deflecting torque ofa moving iron instrument (D) to stop the motor.
ls
(A) P*
5E. While performing short-circuit test on
@);P* transformer the impressed voltage magnitude
is kept constant but the frequency is increased.
The short-circuit curent will
(C) I* (A) increase
(B) decrease
<or jr$ (C) remains same
(D) None of the above
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.lEu17 B-t
59. A choke coil ofinductance L and series rcsistance 64. The voltage across a 5(XK) input circuit of an
R is shunted by a capacitor C. The dynamig iapedangg amplifier is 6V and the output is 30V across a 5fiK)
of the resonant circuit would be load. What is the dB gain of the amplifier?
(A) 13.98 dB
(A)
# (B) 17.98 dB
(B) (c) 1s.98 dB
*
(.)# (D) 11.98 dB
(D)
# 65. The type of single-phase induction motor having
highest power factor at full load is
60. Two Capacitors each having capacitance C and (A) split-phase type
breakdown voltage V arejoined in series. The capacitance . (B) shaded-pole type
and breakdown voltage of the combination will be
(C) capacitor- stafi type
(A) 2C and 2V (D) capacitor-run type
ot | ^a) 616, A 10 mA ammeter has a resistance of 50f). It has
(c) zc ana to be converted to lA ammeter. The value of shunt
] resistance is
P) | mazv (A) so
(B) 0.0so
61. The sag of conductors of a transmission line is (c) 0'5o
2'5m when the span is 250m. If the height of supporting
towers is increase d by 25% , the sag will be
(D) soo
(A) reduced by 25%
(B) increased by 25% 67. A (0 - 5)A PMMC ammeter does not have any
(C) reduced by l2'5% controlling mechanism. Now if a current of 2A(DC) is
passed through the coil, the reading shown by the Meter
(D) remain unchanged would be (frictional opposition is overcome by torque
produced)
62. Transposition of transmission line is done to
(A) 2A
(A) reduce line loss
(B) sA
(B) balance line voltage drop
(C) pointer rotates continuously
(C) reduce skin effect
(D) pointer does not rotate
(D) reduce corona
63. As the transmission voltage increases, the 6lE. Absorption ofsolar radiations on earth's surface
percentage resistance drcp occurs due to presence of
(A) increases (A) Ozone
(B) decreases (B) Water vapours
(C) remains same (C) Carbon dioxide
(D) None of the above (D) All of the above
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B-9 tEEII7
69. The output of solar cell is of the order of 74. Which of the following meters has the best
(A) lw accuracy?
@) sw (A) Moving-imn meter
(c) low (B) Moving-coil meter
(D) 20w (c) Rectifier-type meter
(D) Thennocouple meter
70. An instrument used for measuring total solar
radiation is called
(A) hygrometer 75. An ideal filter is one which
(B) pyranomercr (A) zero attenuates in the pass band.
(C) anemometer (B) infinite atrcnuation in the pass band.
(C) zero attenuation in the attenuation band
@) pyrheliometer
(D) None ofthe above
71. If the capacitance between two conductors of a
3 phase line is 6 pF, the capacitance of each conductor
to neutral will be 76. Circuit breaken usually operate under
(A) 3 FF (A) steady short circuit current.
(B) 12 FF @) sub-transient state of short circuit currcnt.
(C) 6lrF (C) transient state of short circuit current.
(D) Both (A) and (B)
(D) 1'5 rrF
72, For which of reason mentioned below does the 77. A three phase circuit breaker is rated 2000 MVA
electric supply company want to improve the power 33kV. What will be the making current?
factor?
(A) 35kA
(A) To reduce the effective current
(B) 49kA
(B) To rcduce the rcactive cur€nt
(c) 70kA
(C) To reduce the apparcnt curent
@) 89kA
(D) To reduce the voltage drop at the generatiirg
station
7t. Which of the following instruments is used for
73. Sensitivity of a voltmeter is expressed as the comparison of candle powers of different sources?
(A) volUohms (A) Radio meter
@) ohms/volt @) Bunsen meter
(C) ohms volt (C) Photo meter
@) l/ohms volt (D) Candle meter
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Text of page 10
IEE|I7 B-10
79. Forprecision work, the illumination level required 84. From a uniform light source of 300 C.P. there
is of the order of exists a plane surface l5mbelow the valueofillrrmination
(A) 500-10ffi lumen/nr? on the plane surface when the luminous flux rays are
inclined at an angle of 30" to the surface is
(B) 200-400 lumen/m'?
(A) 2'87 lumens
(C) 50-100 lumen/m'?
(B) 1'53 lumens
(D) 10-25 lumen/m2 (C) 5 lumens
(D) 4 06 lumens
80. Output of ongsten filament lamP depends on
(A) size of lamp E5, Which ofthe following is a non-renewable source
of energy?
@) size of shell (A) Wood
(C) temperaore of filament
(B) Sun
(D) All of the above
(C) Fossil fuels
(D) wind
El. Luminous effrciency of a fluorescent lamp is
(A) 70 lumer/watt E6. Fuel cells are
(B) 60 lumen/watt (A) Carbon cell
(C) e10 lumen/watt (B) Hydrogen battery
(D) 30 lumen/watt (C) Nuclear cell
(D) Chromium cell
82. Wavelength for red colour is 87. The function of steel wire in an ACSR conductor
(A) 40004 is to
(B) 50ooA (A) compensate skin effect.
(c) 6oooA (B) take care of surges.
(D) 7000 A (C) provide additional mechanical strenglh.
(D) reduce inductance.
t3. 200 candle power lamp is hung 4m above the 8E. If the terminals of armature of DC motor are
centre of circular area of 5m diameter. The Illumination interchanged, this action will offer following kind of
at cenhe of the area is braking:
(A) l3'5 lux (A) Regenerative braking
(B) 12 5 lux (B) Plugging braking
(C) l7'5 lux (C) Dynamic braking
@) 18'5 lux (D) None of the above
Text of page 11
B-11 JEE|17
t9. Starters are used with DC motors because 94. In case of a transformer,
(A) these motors have high starting torque. (A) volts/tum ofhigh and low voltage windings
(B) thes€ motors are not self-starting. are different.
(C) backemf of these morors isinitially opposing. @) volts/om of high voltage winding is greater
(D) to restrict armature current as there is no than low voltage winding.
back emf while staning. (C) voltytum of low volrage winding is greater
than high voltage winding.
@) voltVom of both low and high voltage
windings are equal.
90, Auto-transformer makes effective saving on
copper and copper losses, when its transformation ratio
is 95. In the transformer following winding has got
more cross-sectional area:
(A) approxinately equal to one
(A) Low voltage winding
@) less than one
(C) greater than one (B) High voltage winding
(C) Primary winding
@) None of the above
(D) Secondary winding
96. The efficiency of the transformer will be
91. Two transformers operating in parallel will share maximum when
the load depending upon their
(A) iron losses is equal to the twice of the copper
(A) leakage impedance losses.
(B) per unit impedance (B) copper losses is equal to the rwice ofthe iron
(C) efficiencies losses.
(D) ratings (C) iron losses is equal to the copper losses.
@) iron losses is equal to the half of the copper
losses.
92. No load current of a transformer has
(A) high magnitude and low power factor. 97. Transformer cores are laminated with
(A) low carbon steel
@) high magnitude and high power factor.
(C) small magnitude and high power factor (B) silicon she€t steel
(C) nickel alloy steel
@) small magrdtude and low power factor.
(D) chromium sheet steel
98. The critical temperature above which the
93. Acommonmethodofcoolingapowertransfomer ferromagnetic materials lose their magnetic property is
ls known as
(A) natural air cmling (A) Curie point
(B) air blast cooling @) Transition temperature
(C) oil cooling (C) Standard temperatwe
@) None of the above (D) None of the above
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Text of page 12
JEH17 B-t2
99. In n-type semiconductor added impurity is llX). The reistance of a conductor of diarnet€r 'd' and
(A) pentavalent length 't' is RO. If the diameter of the conductor is
halved and its length is doubld the resistance will be
@) divalent
(A) RO
(C) tetravaleDt
(B) 2Ro
(D) trivalent
(c) 4R
(D) 8ROfficial key not published for this paper.
Page 1 of 12
Source: West Bengal Public Service Commission. Question paper published by West Bengal Public Service Commission.