SSC/UPPCL JE Electrical Important
MCQ PDF Part 1
1.Hopkinson’s test is conducted at
A) No load
B) Low load
C) Full load
D) Part load
Answer : C
2.How many receptacles can be on a
20-amp circuit
A) 30
B) 40
C) 50
D) 10
Answer : D
3.The magnetic flux which does not
follow the particularly intended path in a magnetic circuit is called
A) Leakage flux
B) Magnetic flux
C) Flux
D) Flux density
Answer : A
4.High voltage DC (HVDC)
transmission is mainly used for
A) Eliminating reactive power
requirement in the operation
B) Minimizing harmonics at the
converter stations
C) Interconnecting two systems with
the same nominal frequency
D) Bulk power transmission over very
long distances
Answer : D
5.AWG stands for
A) Ampacity Wire Gauge
B) American Wire Gauge
C) Actual Wire Gauge
D) Ambient Wire Gauge
Answer : B
6.Which of the following are DC
windings
A) Double layered winding
B) Fractional slot winding
C) Single layered winding
D) Lap winding
Answer : D
7.The speed of a DC machine can be
measured by a/an-
A) Tachometer
B) Ammeter
C) Anemometer
D) Voltmeter
Answer : A
8.Distribution lines in India
generally use
A) RCC poles
B) Wooden poles
C) Steel tower
D) Iron poles
Answer : A
9.A 20 metre length of cable has a
cross-sectional area of 1 mm² and a resistance of 4 Ohm.Calculate the
conductivity of the cable.
A) 4 MS/m
B) 5 MS/m
C) 12 MS/m
D) 10 MS/m
Answer Key : B
10.What is the thermal conductivity
of nichrome
A) 15.5 W·m−1·K−1
B) 11.3 W·m−1·K−1
C) 25 W·m−1·K−1
D) 20.7 W·m−1·K−1
Answer : B
11.______________ is defined as
weber-turns in one coil due to one ampere current in the other.
A) Coefficient of mutual inductance
B) Load coefficient
C) Temperature coefficient
D) Energy efficiency coefficient
Answer : A
12.The r.m.s. value of pure cosine
function is
A) 0.5 of peak value
B) Zero
C) Same as peak value
D) 0.707 of peak value
Answer : D
13.The form factor of a 220 V, 50 Hz
AC waveform is
A) 1.11
B) 0.85
C) 0.95
D) 1.41
Answer : A
14.Which of the following indicates
black and green wires respectively in house wiring
A) Phase and neutral
B) Phase and earth
C) Earth and neutral
D) Neutral and earth
Answer : D
15.The process by which impurities
are added to a pure semiconductor is called
A) Drift
B) Diffusing
C) Doping
D) Mixing
Answer : C
16.Who discovered that a
current-carrying conductor would move when placed in a magnetic field
A) Nikola Tesla
B) Gustav Kirchhoff
C) Michael Faraday
D) Andre Ampere
Answer : C
17.What is the unit of illumination
A) Henry
B) Lux
C) Decibel
D) Coulomb
Answer : B
18.Mutual inductance is measured in
A) Ampere
B) Volt
C) Henry
D) Ohm
Answer : C
19.DC shunt motors are commonly used
in
A) Cranes
B) Lathe machines
C) Electric traction
D) Elevators
Answer : B
20.The starting resistance of a DC
motor is usually
A) Around 1000 Ohms
B) Low
C) Around 100 Ohms
D) Very large
Answer : B
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 2
1.Buchholz relay is installed on
A) Oil cooled transformer
B) Welding transformer
C) Furnace transformer
D) Air cooled transformer
Answer : A
2.A 5 kW, 50 Hz, 6-pole slip-ring
induction motor runs at 960 RPM. Calculate its synchronous speed and percentage
slip.
A) 750 RPM, 2%
B) 900 RPM, 5%
C) 1500 RPM, 4%
D) 1000 RPM, 4%
Answer : D (F=PNs/120 or
Ns=120*F/P=120*50/6=1000 RPM,S=(Ns-N)/Ns=(1000-960)/1000=40*100/1000=4%)
3.Which of the following materials
is not used as fuse element
A) Aluminium
B) Copper
C) Carbon
D) Silver
Answer : C
4.The ratio of active power to
apparent power is known as _________ factor.
A) Load
B) Power
C) Form
D) Demand
Answer : B
5.EMF equation of a transformer with
respect to primary and secondary windings is _______.(where ϕm-flux,
f-frequency, N1-number of turns in the primary winding, N2-number of turns in
the secondary winding, Bm-flux density)
A) All of these
B) E1 = 4.44 f N1 ɸm
C) E1 = 4.44 f N1 BmAi
D) E2 = 4.44 f N2 ɸm
Answer : A
6.The ratio of the maximum power
from the solar cell to the product of short circuit current and open circuit
voltage is known as
A) Peak factor
B) Form factor
C) Fill factor
D) RMS
Answer : C (The Fill Factor
(FF) is essentially a measure of quality of the solar cell. It is calculated by
comparing the maximum power to the theoretical power that would be output at
both the open circuit voltage and short circuit current together.)
7.Which of the following are the
advantages of rotating field in large alternators
A) Improved ventilation arrangement
B) Better insulation to armature
C) Ease of construction
D) All of these
Answer : D
8.In AC parallel circuit the angle
between voltage and current of each branch will be _________.
A) Cannot say
B) Different
C) Same
D) Zero
Answer : B
9.The value of stacking factor is
usually
A) Equal to unity
B) Greater than unity
C) Zero
D) Less than unity
Answer : D (The stacking
factor is the ratio of electrical steel along the axial length of the iron
core.The stacking factor is sometimes also called
lamination factor or space factor.The value of stacking factor
is usually less than unity.)
10.If the equation of sinusoidal
current is 141.4 sin 314t. Find the RMS value and frequency of the current.
A) 400 A and 200 Hz
B) 100 A and 50 Hz
C) 300 A and 150 Hz
D) 200 A and 100 Hz
Answer : B
(V=141.4 sin 314t
On complaining with,V=Vm sin 2πft
We get,2πf=314∴f=314/2π=50Hz
Vm(Peak value)=141.4V
∴Vrms=Vm/√2=141.4V/√2=100V)
11.In which of the following is a
Britannia Tee joint used
A) Underground cables
B) Power wiring
C) Overhead lines
D) Conduit wiring
Answer : C (The Britannia joint is a
form of electrical joint used for bare overhead wires where great tensile
strength is required. The two wires are each tinned, and then each have a short
shoulder bent in them, and are then bound together with tinned wire before the
whole is soldered.)
12.The maximum power transfer
theorem can be applied to
A) DC circuits only
B) Neither AC nor DC circuits
C) AC circuits only
D) Both AC and DC circuits
Answer : D
13.Numbers that are written with
base 8 are classified as
A) Real numbers
B) Hexadecimal numbers
C) Octal numbers
D) Negative numbers
Answer : C
14.The speed of a DC motor is
directly proportional to
A) Flux per pole
B) Speed of motor
C) Back EMF
D) Number of armature conductors
Answer : C
(The back emf equation of DC motor
is given by
Eb=NPφZ/60A
Here, N = speed of rotation in rpm.
P = number of poles. A = number of parallel paths. Z = total no. conductors in
armature.
Thus speed N=60AEb/PZφ
N=Eb/kφ where k=PZ/60A is a constant
Hence, speed of a DC motor is
directly proportional to emf of rotation (E) and inversely proportional to flux
per pole (φ).)
15.In an NPN transistor, P region is
called
A) Emitter
B) Base
C) Collector
D) Source
Answer : B
16.Earthing Practice Rule 33 of
____________ makes it compulsory for licensee to maintain a suitable earthed
terminal.
A) Indian Electricity Rules 1960
B) Indian Electricity Rules 1956
C) Indian Electricity Rules 1950
D) Indian Electricity Rules 1966
Answer : B (Earthing Practice
Rule 33 of Indian Electricity rules 1956 makes it compulsory for
licensee to maintain a suitable earthed terminal in consumer’s premises)
17.Which of the following type of
wattmeters is used only on AC
A) Induction type wattmeter
B) Dynamometer type suspended-coil
torsion wattmeter
C) Dynamometer type pivoted-coil
directreading wattmeter
D) Electrostatic type wattmeter
Answer : A
18.TRS cables on batten are suitable
for places
A) Not exposed to sun and rain
B) Exposed to atmosphere
C) Fire hazard is present
D) Where acids and alkalis are
present
Answer : A (The disadvantages of
batten wiring are Not suitable for outdoor wiring)
19.The PIV rating of 1N4007
rectifier diode is
A) 600 V
B) 1000 V
C) 200 V
D) 400 V
Answer : B (1N4007 is
a rectifier diode, designed specifically for circuits that need to convert
alternating current to direct current. It can pass currents of up to 1 A, and
have peak inverse voltage (PIV) rating of 1,000 V)
20.Joint box wiring method might be
cheaper with respect to
A) Cost wise
B) Power saving
C) Cable length
D) Labour
Answer : C (Joint Box or Tee
or Jointing System-In this method of wiring, connections to appliances are made
through joints. These joints are made in joint boxes by means of suitable
connectors or joints cutouts. This method of wiring doesn’t consume too much
cables size.)
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 3
1.If one of the parallel resistors
in any parallel circuit is removed from the circuit, then the total resistance
A) Doubled
B) Increases
C) Remains the same
D) Decreases
Answer : B
2.AC servomotor is basically a
_______
A) Single-phase induction motor
B) Three-phase induction motor
C) Universal motor
D) Two-phase induction motor
Answer : D
3.In a three-phase unbalanced load,
the power factor of each phase is
A) Of opposite signs
B) Of such value that the sum total
is unity
C) Difficult to determine
D) Different
Answer : D
4.Which of the following devices is
primarily used as resistive temperature sensors and current limiting devices
A) NTC thermistor
B) Rheostat
C) Light dependent resistor
D) Preset resistor
Answer : A
5.Channel wiring material is made of
_______
A) Rubber
B) Metal
C) PVC
D) Wood
Answer : C ( Wiring channels are
made of high grade PVC materials.PVC enclosures are widely used in electrical
wiring systems of domestic and commercial buildings)
6.The colour of the moist silica gel
is
A) Brown
B) Yellow
C) Pink
D) Red
Answer : C (Ready to use silica gel
is blue in colour. When the silica gel has soaked up a lot of
moisture, the silica gel turns to pink. Once the silica gel
turns pink it cannot adsorb any more moisture)
7.Which of the following errors
occur(s) in a moving iron instrument
A) Stray magnetic field error
B) Hysteresis error
C) All of these
D) Temperature error
Answer : C
8.Megger is a combination of
A) Generator
B) Motor
C) Generator and Ohmmeter
D) Both motor and generator
Answer : C (Megger is the combination of Ohm
meter+Generator.This instrument used for measure the high value resistance (IR
value)
9._____________ theorem is
applicable to both linear and nonlinear circuits.
A) Norton’s
B) Substitution
C) Thevenin’s
D) Superposition
Answer : B (Substitution theorem
states that any branch in a network can be substituted by a different branch
without disturbing the currents and voltages in the whole network provided the
new branch has the same set of terminal voltages and current as the original
branch. Substitution theorem can be used in both linear and nonlinear circuits)
10.______________ wiring(s) is/are
used to draw TRS cables on teak wood.
A) Lead sheathed
B) PVC
C) Cleat
D) Batten
Answer : D (In Batten Wiring System
wooden batten is used. All the cables wiring are installed on
the smooth batten with steel clips and steel clips are installed on
the surface of batten to equal The wooden batten is installed on
the walls of the with the help of 1.5 inch screws)
11.___________ is a circuit, which
converts an AC voltage into a pulsating DC voltage using both half cycles of
the applied AC voltage.
A) BJT
B) FET
C) Full wave rectifier
D) Half wave rectifier
Answer : C
12.Which of the following excitation
systems have two exciters – the main exciter and a pilot exciter
A) Stator
B) Rotor
C) DC
D) Static
Answer : C (In dc excitation
system, the system has two exciters—the main exciter (a
separately excited dc generator providing the field current to the
alternator) and a pilot exciter (a compound wound self-excited dc generator
providing the field current to the main exciter))
13.Joule’s heating effect is
undesirable on
A) Electric iron
B) Electric heater
C) Electric toaster
D) Transformers
Answer : D
14.Crawling in an induction motor is
caused by
A) Harmonics developed in the motor
B) Low voltage supply
C) High loads
D) Improper design of the machine
Answer : A
15.Windings of star-delta starter
while starting and during running are connected in __________connection.
A) Delta and star
B) Star and star
C) Delta and delta
D) Star and delta
Answer : A
16.A shunt generator running at 1000
RPM has generated EMF of 100 V. If the speed increases to 1200 RPM, then the
generated EMF will be
A) 120 V
B) 240 V
C) 175 V
D) 140 V
Answer : A (E2/E1=N2/N1 Or
E2/100=1200/1000 So E2=120 V)
17.If three 10 μF capacitors are
connected in series, then the value of equivalent capacitance is
A) 3.33 μF
B) 1.33 μF
C) 1.66 μF
D) 0.3 μF
Answer : A (1/C=1/10+1/10+1/10 Or
C=10/3=3.33 μF)
18.Q meter works on principle of
A) Self inductance
B) Parallel resonance
C) Mutual inductance
D) Series resonance
Answer : D
19.A fuse operates due to the
_______ effect of electric current.
A) Electrostatic
B) Heating
C) Magnetic
D) Chemical
Answer : B
20.The point at which load line
intersects IB(sat) (saturation value of base current) is called
A) Cut off point
B) Quiescent point
C) Breakdown point
D) Saturation point
Answer : D
(The point where the load line
intersects the IB = IB(sat) curve is called
saturation)
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 4
1.The number of poles in a turbo
alternator are
A) 10
B) 6
C) 2
D) 8
Answer : C
2.A/an ______ is used in electrical
installation to join some conductors and provide different paths for different
conductors.
A) Capacitor
B) Fuse
C) Ceiling rose
D) Junction box
Answer : D (Junction
boxes are metal or plastic enclosures used as housings for
wiring connections. The connections within are called branch circuits and
usually represent the end of a conduit run)
3.The number of depletion layers in
a BJT transistor is-
A) Four
B) Three
C) Five
D) Two
Answer : D
4.The effect of fringing __________
with the increase in the length of the air gap in magnetic circuits.
A) Remains constant
B) Decreases
C) Becomes zero
D) Increases
Answer : D (Fringing is
directly proportional to the length of the air gap that means if
the length increases the fringing effect will also be more and
vice versa.)
5.Neutral is a circuit conductor
that normally carries _________ back to the source.
A) Current
B) Power
C) Flux
D) Voltage
Answer : A (Neutral is a
circuit conductor that normally carries current back to the source, and is
connected to ground (earth) at the main electrical panel)
6.The power factor of synchronous
generator depends on
A) Load
B) Core losses
C) Armature losses
D) Speed of rotor
Answer : A
7.Low resistance value can be
measured accurately by using a/an
A) Megger
B) Ohmmeter
C) Kelvin double bridge
D) Multimeter
Answer : C
8.An SCR has _______ PN junctions.
A) 3
B) 4
C) 2
D) 5
Answer : A
9.An electric stove consumes 5 MJ of
energy from a 230 V power supply when turned on for 60 minutes. Find the
approximate power.
A) 1389 W
B) 1772 W
C) 1500 W
D) 1823 W
Answer : A (P = W / t,P =
(5 MJ) (106 J/MJ) / ((60 min) (60 s/min))=1389 W= 1.39 kW)
10.The frequency of an alternating
quantity is
A) The speed with which the
alternator runs
B) The number of direction reversals
per second
C) The number of cycles completed
per minute
D) The number of cycles completed
per second
Answer : D
11.In which of the following
applications is armoured cable used
A) Teak wood batten wiring
B) Domestic portable appliances
C) General wiring
D) Underground systems for
distribution purpose
Answer : D
12.The average value of the current
is the _____________ divided by the number of currents.
A) Sum of all resistances
B) Sum of all voltages
C) Sum of all currents
D) Sum of all currents and voltages
Answer : C
13.In a closed loop, the sum of
voltage drops across components is equal to
A) Zero
B) Half the applied voltage
C) Twice the applied voltage
D) The applied voltage
Answer : D
14.________ at a point is defined as
the force experienced per unit positive charge at a point placed in the
electric field.
A) Magnetic flux density
B) Electric intensity
C) Electric flux
D) Voltage rating
Answer : B
15.The EMF of a generator depends
on-
A) Number of poles
B) Number of parallel paths
C) Flux per pole
D) All of these
Answer : D (E=PZNφ/60A)
16.Which lamp has the best Colour
Rendering Index (CRI)
A) Fluorescent
B) Incandescent
C) LED
D) High pressure sodium vapour
Answer : B (The Color
Rendering Index (CRI) is a scale from 0 to 100 percent indicating how accurate
a “given” light source is at rendering color when compared to a “reference”
light source.Fluorescent-76,Incandescent-100,LED-83,High pressure sodium
vapour-24)
17.A multimeter can measure
A) All of the options
B) Voltage
C) Current
D) Resistance
Answer : A
18.What is the binary representation
of 73
A) 1001100
B) 1001101
C) 1001001
D) 1001111
Answer : C
(Step 1: Divide (73)10
successively by 2 until the quotient is 0
73/2 = 36, remainder is 1
36/2 = 18, remainder is 0
18/2 = 9, remainder is 0
9/2 = 4, remainder is 1
4/2 = 2, remainder is 0
2/2 = 1, remainder is 0
1/2 = 0, remainder is 1
Step 2: Read from the bottom (MSB)
to top (LSB) as 1001001.
So, 1001001 is the binary equivalent
of decimal number 73)
19.The armature reaction affects the
___________ when the load on an alternator is increased.
A) Rotor speed
B) No load losses
C) Frequency of armature
D) Terminal voltage
Answer : D
20.The expression for synchronous
speed is _________ where Ns-synchronous speed, ffrequency,P-number of poles.
A) Ns = 120Pf
B) Ns = 120f/P
C) N s= 120P/f
D) Ns = 120/Pf
Answer : B
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 5
1.What is the expansion of DPIC
switch
A) Digital Pole Iron Clad Switch
B) Double Pole Iron Clad Switch
C) Double Phase Induction Core
Switch
D) Dual Phase Iron Clad Switch
Answer : B (DPIC stands
for Double Pole Iron Clad Switch)
2.The number of magnetic starter
poles refer to the
A) Number of north poles
B) Number of control contacts
C) Number of south poles
D) Number of power load contacts
Answer : D
(The number of poles refers to the number of
power contacts determined by the electrical supply service. E.g., in a
three-phase, three-wire system, a three-pole starter is required)
3.If an alternator winding has a
fractional pitch of 5/6, the coil span is _______ degrees.
A) 180
B) 60
C) 300
D) 150
Answer : D (Coil
spam=180⁰×5/6=150⁰)
4.Ammeter should always have a
A) Low resistance
B) High voltage
C) Low voltage
D) High resistance
Answer : A
5.Reverse Power flow relays are used
for the protection of _______
A) Generating stations
B) Transmission stations
C) Transformers
D) Domestic power supplies
Answer : A (Reverse Power
Relay is a directional protective relay that prevents/protect
the generator from motoring effect (going to reverse direction). It is
used where generator runs in parallel with other utility or generator)
6.Which of the following wiring
systems is normally used in domestic purposes
A) Lead Sheathed
B) Conduit
C) Batten
D) Capping
Answer : B (Conduit wiring
system mostly used in residential and light-commercial wiring
systems, including common applications)
7.Which of the following types of
wiring are aesthetically appealing
A) Conduit concealed wiring
B) Batten wiring
C) Cleat wiring
D) Conduit surface wiring
Answer : A (Concealed
Conduit Electrical Wiring systems are the most popular,
aesthetically appealing, and most common type of House
Electrical wiring used)
8.What is the average power of an AC
circuit
A) VI Sin²Φ
B) VI CosΦ
C) VI SinΦ
D) Zero
Answer : B
9.The knee voltage for a germanium
diode is
A) 0.3 V
B) 0.1 V
C) 0.7 V
D) 0.8 V
Answer : A (The value of
knee voltage for silicon diode is 0.7 V and for germanium diode 0.3
V)
10.The minimum number of diodes
needed for a bridge rectifier is
A) Five
B) Four
C) Two
D) Six
Answer : B
11.Why are batteries connected in
parallel
A) To increase the efficiency
B) To increase the current capacity
C) To increase the voltage rating
D) To increase the life of the
batteries
Answer : B
12.A winding which has equal number
of slots and poles is called
A) Full pitch winding
B) Concentrated winding
C) Short pitch winding
D) Distributed winding
Answer : B (Concentrated
winding:Concentrated winding is employed where number of slots on the armature
is equal to number of poles in the machine)
13.A semiconductor device which acts
like a diode and two transistors is
A) MOSFET
B) TRIAC
C) UJT
D) DIAC
Answer : B (The triac is
similar in operation to two transistor connceted in reverse parallel but using
a common gate. The triac can conduct in both direction)
14.The Tellegen’s theorem can be
applied to
A) Passive & active networks
B) All of these
C) Hysteric and non-hysteric
networks
D) Linear & non-linear networks
Answer : B
15.The connection of a Zener diode
in a circuit is always
A) Positively biased
B) Reverse biased
C) In series
D) Forward biased
Answer : B
16.Induction motor works on the
principle of
A) Chemical effect
B) Heating effect
C) Electromagnetic induction
D) Electrostatic effect
Answer : C
17.What is the length of a 40 watt
tube
A) 0.6 m
B) 1.5 m
C) 2 m
D) 1.2 m
Answer : D (20 watt-2 ft (610 mm),40
watt-4 ft (1219 mm))
18.A circuit breaker normally
operates
A) Whenever a fault occurs in the
line
B) When the power is to be supplied
C) When the switch is to be put on
D) When the line is to be tested
Answer : A
19.Solder is an alloy of
A) Lead and copper
B) Lead and silver
C) Lead and tin
D) Lead and sodium
Answer : C
20.According to weber’s molecular
theory of magnetism, when a magnetic material is magnetised,its molecules are
forced along a __________.
A) Parallel line
B) Straight line
C) Circular line
D) Spherical line
Answer : B (According to Weber’s
Molecular Theory of magnetism, when a magnetic material is magnetised, its
molecules are forced along a straight line
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 6
1.For domestic wiring, the most
extensively used material is
A) Aluminium
B) Copper
C) Neither copper nor aluminium
D) Copper or aluminium
Answer : D
2.A substance that has a high
retentiveness can be used for the manufacture of
A) Electromagnets
B) Paramagnets
C) Temporary magnets
D) Permanent magnets
Answer : D
3.For a slip ‘s’ and supply
frequency ‘f’, the frequency of current in rotor will be
A) sf
B) f/s
C) f²/s
D) (1-s)f
Answer : A
4.The synchronous speed of a three
phase induction motor having 20 poles and connected to a 50 Hz source is
A) 1200 RPM
B) 600 RPM
C) 300 RPM
D) 1000 RPM
Answer : C (Ns=120*f/P=120*50/20=300
RPM)
5.The ballistic galvanometer is
designed to deflect its needle proportional to ________ passing through its
moving coil.
A) Heat energy
B) Magnetic force
C) Pressure energy
D) Charge
Answer : D (The ballistic
galvanometer is designed to deflect its indicating needle (or
mirror) in a way that is proportional to the total charge passing
through its moving coil or to a voltage pulse of short duration)
6.Which of the following
semiconductor devices can be used for controlling the speed of a DC motor
A) Thyratron
B) Thermistor
C) Transistor
D) Thyristor
Answer : D
7.Equipment earthing is necessary to
give protection against
A) Overloading
B) The danger of electric shocks
C) Voltage fluctuation
D) The high temperature of the
conductors
Answer : B
8.In a transmission system, a feeder
feeds power to
A) Power plant substation
B) Generating substations
C) Service mains
D) Distributors
Answer : B
(Feeder transmits power from Generating station or substation to the
distribution points)
9.An alternator has 20 poles and
running at 300 RPM will generate alternating voltage and current whose
frequency is
A) 100 Hz
B) 50 Hz
C) 30 Hz
D) 40 Hz
Answer : B
(f=PN/120=20*300/120=50 Hz)
10.When a voltmeter-ammeter method
is applied for the measurement of resistance, the voltmeter reads a value of
8.28 V and the ammeter reading is 4.14 mA, then the value of the resistance
will be
A) 20 kΩ
B) 2 kΩ
C) 200 kΩ
D) 2 MΩ
Answer : B (R=V/I=8.28 V/ 4.14
mA=2 kΩ)
11.The fusing factor of protective
devices for medium level load is
A) 1.45
B) 2.38
C) 3.45
D) 0.95
Answer : B (Fusing factor
=minimum fusing current / current rating of fusing
element. Fusing factor value is more than 1.The fusing factor of
protective devices for medium level load is 1.45)
12.The difference between the
synchronous speed and the actual speed of an induction motor is known as
A) Backlash
B) Lag
C) Slip
D) Regulation
Answer : C (s=Ns-N)
13.Where is the control grid placed
in a triode
A) Very near to cathode
B) Very near to plate
C) Very near to anode
D) Midway between plate and cathode
Answer : D
14.Relative permeability of a
substance is less than the permeability of free space is known as
A) Paramagnetic
B) Non magnetic
C) Diamagnetic
D) Ferromagnetic
Answer : C
(A diamagnetic material has a constant relative permeability slightly
less than 1.The permeability of free space (a vacuum ) is
a physical constant equal to approximately 1.257 x 10 –6
henry per meter)
15.If a power of 100 W is being
supplied across a potential difference of 200 V, find the current flowing
through the circuit.
A) 0.5 A
B) 1 A
C) 20 A
D) 2 A
Answer : A (I=P/V=100/200=0.5
A)
16.Electricity produced from _______
is called piezoelectricity.
A) Heat
B) Pressure
C) Light
D) Velocity
Answer : B (Piezoelectricity
means the electricity which is produced due to the application of pressure)
17.If the load impedance in three
phases are not equal to the load then it is said to be
A) Unbalanced supply
B) Unbalanced load
C) Balanced supply
D) Balanced load
Answer : B
18.Susceptibilities of diamagnetic
material is
A) Unity
B) Zero
C) Negative
D) Positive
Answer : B (Diamagnetic
substances have negative susceptibilities (χ < 0);
paramagnetic, superparamagnetic, and ferromagnetic substances have
positive susceptibilities (χ > 0))
19.Which of the following wirings is
suitable for lighting in low voltage installations
A) Surface conduit wiring
B) Concealed conduit wiring
C) TRS wiring
D) Casing wiring
Answer : C
20.Which of the following are the
disadvantages of synchronous motors
A) Usually operate with higher
efficiencies
B) Requires DC excitation
C) Ability to control the power
factor
D) Electro-magnetic power varies
linearly with the voltage
Answer : B
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 7
1.At resonance frequency, the
inductive reactance value is the same as
A) Reactance of the capacitor
B) Impedance of the circuit
C) Resistance of the circuit
D) Reactance of the coil
Answer : A (At
the resonant frequency fr, XL = XC)
2.Which of the following is NOT a
standard transmission voltage
A) 222 kV
B) 750 kV
C) 400 kV
D) 132 kV
Answer : A
(Nominal System Voltage in kV 132 220 275 345 400 500
750 Maximum Operating Voltage in kV 145 245 300 362 420 525 765)
3.If there are “n” nodes in the
circuit there will be ________ independent nodal equations.
A) n+1
B) n-2
C) n
D) n-1
Answer : D
4.Open circuit test on transformers
is conducted to determine which of the following
A) Core losses
B) Eddy current losses
C) Hysteresis losses
D) Copper losses
Answer : A (Open circuit test
is conducted to find the core/iron loss of a transformer,Core losses is
the sum of the hysteresis loss and the eddy current loss)
5.Which of the following motors is
employed in hair dryers
A) Capacitor start induction motor
B) Split phase induction motor
C) Capacitor start capacitor run
induction motor
D) Shaded pole induction motor
Answer : D
6.The wire of 2 SWG is equivalent to
diameter of
A) 7.01 mm
B) 5.89 mm
C) 5.38 mm
D) 6.4 mm
Answer : A (1 Swg = 7.620mm,2
Swg = 7.010mm,3 Swg = 6.401mm,4 Swg = 5.893mm,5 Swg = 5.385mm)
7.Which of the following diodes is a
signal diode
A) 0A79
B) BY127
C) 1N4007
D) DR25
Answer : A (0A79 diodes-The
symbol ‘A’ indicates that this device is made from germanium,As germanium has
less cut in voltage so this diode is used for low power signal or for signal
processing)
8.If a 100 Watts bulb is ON for 10
hours, then what will be the amount of electricity consumed
A) 1500 Watts
B) 1 kWh
C) 300 Watts
D) 100 Watts per hour
Answer : B (Amount of
electricity consumed=100 x 10 = 1000 Watt-Hour = 1
Kilowatt-Hour (kWH) = 1 units)
9.If the battery of a multimeter
becomes weak, then it will give
A) Perfect reading
B) High reading
C) No reading
D) Less reading
Answer : D
10.A component which is used to
close or break a circuit is called
A) Electric cell
B) Wire
C) Switch
D) Bulb
Answer : C
11.Which of the following is a
possible cause of blackening at both ends of the fluorescent lamp
A) Frequent starting of fluorescent
lamp
B) Improper ballast
C) Low or high voltage
D) All of these
Answer : D
12.When the rotor of a three-phase
induction motor runs at synchronous speed, its rotor frequency will become
A) Zero
B) Half of supply frequency
C) Equal to the supply frequency
D) Double the supply frequency
Answer : A
13.The total opposition offered to
the flow of current in AC circuit is called
A) Inductance
B) Resistance
C) Impedance
D) Capacitance
Answer : C
14.To measure which of the following
is Wheatstone bridge method used
A) Voltage
B) Resistance
C) Power
D) Current
Answer : B
15.In a megger, controlling torque
is provided by
A) Gravity
B) Eddy current
C) Coil
D) Spring
Answer : C
16.The spindle of the moving system
in a PMMC instrument is supported at both ends with the help of
A) Bush bearings
B) Jewelled bearings
C) Gun metal bearings
D) Steel bearings
Answer : B
17.The electric displacement of a
winding in two-phase supply is
A) 180°
B) 90°
C) 120°
D) 60°
Answer : B
18.In a 2 pole lap winding DC
machine, the resistance of one conductor is 2 Ω and the total number of
conductors is 100. Find the total armature resistance.
A) 200 Ω
B) 50 Ω
C) 100 Ω
D) 10 Ω
Answer : B (Total armature
resistance=X×Z/A² Where X = Resistance of one conductor Z = Total number of
conductors A = No of parallel paths-For lap winding it is 2,So total armature
resistance=2×100/2²=50 Ω)
19.The rotor in an alternator
requires
A) Pulsed DC
B) Triangular wave
C) AC
D) DC
Answer : D (An alternator is
a synchronous machine and the field winding on the rotor is designed
for DC)
20.Three-phase transformer contains
A) One primary and three secondary
windings
B) Three primary and one secondary
windings
C) Three primary and three secondary
windings
D) Three primary and two secondary
windings
Answer : C
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 8
1.________ extinguishers are ideal
for places with a lot of electrical equipment such as offices or server rooms.
A) N2S
B) Cl2
C) SO2
D) CO2
Answer : D
2.What is the average life of a fluorescent
tube
A) 2000 hours
B) 7000 hours
C) 1000 hours
D) 3000 hours
Answer : B (Fluorescent light
bulbs typically have a rated lifespan of 7,000 to 15,000 hours)
3.An ON-OFF switch with overload
protection is called a _______.
A) Reversing starter
B) Magnetic starter
C) Manual starter
D) Combination starter
Answer : C (Manual motor
starters are electro-mechanical protection devices for the main circuit. They
are used mainly to switch motors manually ON/OFF and protect them fuse less
against short-circuit, overload and phase failures. )
4.When checked with an ohm meter an
open resistor reads
A) High but within tolerance
B) Zero
C) Infinite
D) Low but not zero
Answer : C
5.The winding of interpoles is
connected ________ with the armature.
A) Half in series and half in
parallel
B) Both in series and parallel
C) In parallel
D) In series
Answer : D
6.The EMF induced in a coil due to
the change of its own flux linked with it is called
A) Dynamically induced EMF
B) Self induced EMF
C) Mutually induced EMF
D) Statically induced EMF
Answer : B
7.In an alternator, the _______
current is generated in the stationary stator.
A) DC
B) Both AC and DC
C) Pulsating DC
D) AC
Answer : D (The rotating
magnetic field induces an AC voltage in the stator windings)
8.The speed with which the turbo
alternators operate are
A) 3000 RPM
B) 5000 RPM
C) 1000 RPM
D) 1500 RPM
Answer : A (The normal
speed of a turbo generator is 1500 or 3000 rpm with four or two poles
at 50 Hz (1800 or 3600 rpm with four or two poles at 60 Hz))
9.Two bulbs of 500 W and 200 W rated
at 250 V will have resistance ratio as
A) 2 : 3
B) 2 : 5
C) 3 : 2
D) 5 : 2
Answer : B (Resistance of bulb
500 watt R₁=(220)²/500Ω,Resistance of bulb 200 watt R₂=(220)²/200Ω So
R₁/R₂=2/5)
10.A quantity whose magnitude has a
definite repeating time cycle is called a
A) Steady state periodic
B) Transient state periodic
C) Steady state aperiodic
D) Transient
Answer : A
11.________ system is universally
adopted for a generation, transmission and distribution of electric power.
A) Two phase
B) Single phase
C) Both single and two phase
D) Three phase
Answer : D
12.Resonant Grounding is also known
as
A) Solid earthing
B) Arc suppression coil earthing
C) Reactance earthing
D) Resistance earthing
Answer : B
13.RMS value is defined based on
which of the following
A) Charge transfer
B) Voltage
C) Current
D) Heating effect
Answer : D (Rms (Root
mean square) value is defined based on heating effect of wave-forms)
14.In a permanent magnet moving coil
instrument, the deflecting torque is directly proportional to
A) Current passing through coil
B) Flux density in air gap
C) Number of turns of coil
D) All of these
Answer : D (Td =
NBldI where N is number of turns,B is magnetic flux density in air
gap,l is the length of moving coil,d is the width of the moving coil,I is the
electric current)
15.Which of the following effects is
used in Wattmeter
A) Chemical effect
B) Electrostatic effect
C) Electrodynamic effect
D) Thermal effect
Answer : C
16.When an electric device,
appliance or electrical installation is connected to the earth electrode
without a fuse, circuit breaker or resistance/Impedance, It is called
___________.
A) Solidly earthed
B) Earth resistance
C) Earthing lead
D) Earth continuity conductor
Answer : A
17.According to Kirchhoff’s current
law, the algebraic sum of current leaving a node in a lumped parameter circuit
is equal to
A) Value of voltage drop in the
circuit
B) Infinite
C) Unity
D) Zero
Answer : D
18.The measurement errors mainly
caused by human mistakes are called
A) Gross error
B) Systematic error
C) Instrumental error
D) Observational error
Answer : A
19.Before starting electroplating,
what action is to be necessarily taken
A) Buffing
B) Soldering
C) Cleaning
D) Polishing
Answer : C
20.In which of the following
transmission lines is capacitance effect negligible
A) Both long transmission lines and
short transmission lines
B) Short transmission lines
C) Long transmission lines
D) Medium transmission lines
Answer : B
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 9
1.Which of the following are the
types of earthing system
A) Wire earthing
B) All of these
C) Pipe earthing
D) Plate earthing
Answer : B
2.Alternator is used to generate
A) Both AC and DC
B) DC
C) Light energy
D) AC
Answer : D
3.Working voltage of medium grade
cables is
A) 500 V
B) 650 V
C) 100 V
D) 400 V
Answer : B
4.Mho relay is suitable for
__________ transmission lines
A) Low voltage
B) Ultra High voltage
C) Both Ultra and extra high voltage
D) Extra-high voltage
Answer : C
5.The base of BJT is
A) Heavily doped
B) Moderately doped
C) Not doped
D) Lightly doped
Answer : D (The
base region of a BJT transistor is very thin and is lightly
doped with current carriers)
6.In an airblast circuit breaker,
why is compressed air used
A) Closing the contacts
B) Cooling the circuit breaker
C) Quenching the arc
D) Opening the contacts
Answer : C
7.Filament in an incandescent lamp
is made of
A) Copper wire
B) Nichrome wire
C) Fuse wire
D) Tungsten wire
Answer : D
8.A coil of 600 turns and of
resistance of 20 Ω is wound uniformly over a steel ring of mean circumference
30 cm and cross sectional area 9 cm². If the relative permeability of the ring
is 1600. Find the value of reluctance.
A) 1.657 x 10⁵ AT/Wb
B) 2.657 x 10⁵ AT/Wb
C) 3.657 x 10⁵ AT/Wb
D) 4.657 x 10⁵ AT/Wb
Answer : A (Given l=30 cm=0.3
m,A=9 cm²=9×10⁻⁴ m²,μᵣ=1600,μₒ=4π×10⁻⁷ Reluctance
S=l/μᵣμₒA=0.3/1600×4π×10⁻⁷×9×10⁻⁴=1.657 x 10⁵ AT/Wb)
9.The full form of ACSR is
A) All Copper Standard Reinforced
B) Aluminium Conductor Steel
Reinforced
C) All Copper Steel Reinforced
D) Aluminium Copper Steel Reinforced
Answer : B
10.Leakage coefficient is denoted by
A) φ
B) Ω
C) μ
D) λ
Answer : D (The ratio of the
total flux produced to the useful flux set up in the air gap of the magnetic
circuit is called a leakage coefficient or leakage factor. It is denoted by
(λ).)
11.Power is transmitted over
transmission lines on high voltage, because
A) Current is reduced
B) Efficiency is increased
C) Conductor cost is reduced
D) Both conductor cost is reduced
and efficiency is increased
Answer : D
12.What is the primary function of a
choke in a tube light circuit
A) Limit the starting current
B) Limit the current after starting
C) Heat up the filament
D) Induce high voltage
Answer : D (The purpose of
the choke is to provide a very high voltage initially between the
filaments (across the two ends of the tube light))
13.What is the purpose of shading
coil in a shaded pole motor
A) Reduce rotational losses
B) Produce rotating magnetic field
C) Reduce friction loss
D) Reduce rough commutation
Answer : B
14.A P-N-P-N diode
A) May be made of any semiconductor
B) Is always made of germanium
C) May be made of either silicon or
germanium
D) Is always made of silicon
Answer : D (The Shockley diode
or PNPN diode is a four layer (P-N-P-N), two terminals (namely anode and
cathode) semiconductor switching device.PNPN used silicon and phosphorus)
15.The rotor current frequency in a
slip-ring induction motor depends on
A) Amount of slip
B) Inductive reactance
C) Rotor inductor
D) Rotor conductor
Answer : A (Rotor frequency =
s*f)
16.A magnetic pressure which sets up
or tends to set up flux in a magnetic circuit is called
A) Magnetic field
B) Cross magnetisation
C) Demagnetisation
D) Magnetomotive force
Answer : D
17.During raceway wiring, which
colour wire is always used for neutral connections
A) Red
B) White
C) Either green or white
D) Green
Answer : B (Black, Red and
Blue are used for hot wires and White is used as the neutral wire in a 120/208
V circuit/ raceway wiring. Brown, Orange and Yellow are used as hot
wires and gray is used as the neutral wire in a 277/480 V. For grounding,
regardless of the voltage, Green (or a bare wire) is used)
18.Ceiling rose is used to take
supply for a/an
A) Portable equipment
B) Fluorescent lamp
C) Electric iron
D) Heater of 2000 W
Answer : B (A ceiling
rose is used to make a safe and efficient connection between the
circuit wiring of an installation au electric load such as, fan, lamp,
fluorescent tube etc).
19.The thyristor is turned off when
the anode current falls below
A) Holding current
B) Latching current
C) Forward current
D) Breakover current
Answer : A
20.In India, what is the frequency
of the AC power line voltage
A) 120 Hz
B) 60 Hz
C) 100 Hz
D) 50 Hz
Answer : D
SSC/ UPPCL JE Electrical Important
MCQ PDF Part 10
1.If a three-phase motor operates
with only two-phases, it is called single-phasing. It will ultimately make the
motor _______.
A) To run with triple speed
B) To run efficiently
C) To carry no load
D) To burn out
Answer : D (When a three phase
motor looses one of the phase supply voltage then it is called Single Phasing.
Single Phasing a case when any one phase out of the three phases fails.Since
one of the phases is now disconnected, current through other two phases will
increase to produce the desired torque. The motor will run but would not be
able to drive rated load.If motor is operating at higher load near to the rated
load,Motor may get burnt)
2.Two way switches are used in ____
wiring
A) Staircase
B) Lead sheathed
C) Conduit
D) Batten
Answer : A
3.Which of the following diodes
operate(s) in reverse breakdown region
A) Both PN junction diode and zener
diode
B) LED
C) PN junction diode
D) Zener diode
Answer : D
4.A cluster of charges with an
electric dipole moment is often called
A) Electric dipoles
B) Polarization
C) Electric susceptibility
D) Eddy currents
Answer : A
5.Paramagnetic substances are
A) Weakly attracted by a magnet
B) The same as that of dia magnetic
substances
C) Weakly repelled by a magnet
D) Produced by heating iron above
the curie point
Answer : A (These are metals
that are weakly attracted to magnets. They include aluminum, gold, and copper)
6.A JFET is also called ________
device
A) Neither unipolar nor bipolar
B) Both unipolar and bipolar
C) Unipolar
D) Bipolar
Answer : A (All FETs can be
called UNIPOLAR devices because the charge carriers that carry the current
through the device are all of the same type i.e. either holes or electrons, but
not both)
7.Calculate the total DC resistance
of a 100 metre roll of 2.5 mm² copper wire if the resistivity of copper at 20°
C is 1.72 x 10⁻⁸ Ω metre.
A) 0.867 Ω
B) 0.713 Ω
C) 0.214 Ω
D) 0.688 Ω
Answer : D (Given
resistivity of copper at 20oC is 1.72 x 10-8, coil length
L = 100m, the cross-sectional area A= 2.5mm2 = 2.5 x 10-6 metres2,R=ρL/A
So R=1.72 x 10⁻8×100/ 2.5 x 10⁻⁶=688 mΩ=0.668 Ω)
8.The property of the coil of
generating induced EMF due to the changing flux linked with it is called
A) Reactance
B) Capacitance
C) Resistance
D) Inductance
Answer : D
9.What is the SI unit of electric
charge
A) Volt (V)
B) Joule (J)
C) Coulomb (C)
D) Ampere (A)
Answer : C
10.What is the most common and
important type of fuse used in domestic application
A) Liquid type fuse
B) Kit-Kat type fuse
C) HRC fuse
D) Cartridge fuse
Answer : B (Rewirable or Kit –
Kat Type Fuses are a type of Low Voltage (LV) Fuses. They are most commonly
used in house wiring, small industries and other small current applications)
11.In P-type semiconductor, the
majority carriers are
A) Valence electrons
B) Free electrons
C) Neutrons
D) Holes
Answer : D
12.Which of the following value of a
complex current wave is equal to the square root of the sum of the square of
the RMS value of the individual components
A) Average value
B) Mean value
C) RMS value
D) Peak value
Answer : C (The rms
value of complex current or voltage wave is equal to the square root
of the sum of the squares of the rms value of its individual
components)
13.Synchronous motor when used for
power factor improvement should be
A) Operated at no load with under
excitation
B) Operated with load
C) Connected along with capacitor
bank
D) Operated at no load with over
excitation
Answer : D
14.The armature current of a
synchronous motor has large value for
A) High excitation
B) Medium excitation
C) Both low and high excitation
D) Low excitation
Answer : C (The magnitude of
armature current varies with excitation. The current has large value both for
low and high values of excitation (though it is lagging for low excitation and
leading for higher excitation))
15.The unit of current is
A) Hertz
B) Volt
C) Ampere
D) Coulomb
Answer : C
16.The centre tap transformer is
used in
A. Quarter Wave Rectifier
B. Half Wave Rectifier
C. Full Wave Rectifier
D. Bridge Rectifier
Answer : C
17.The important advantage of FET
over BJT is
A. Very High Input Resistance
B. Very Low Input Resistance
C. Very High Input Current
D. Zero input Resistance
Answer : A
18.What is the speed of an induction
motor when slip is 100%
A. Zero
B. Full load speed
C. Half load Speed
D. Quarter load speed
Answer : A (s = (ns –
nr) 100% / ns ,where s = slip ns =
synchronous speed of magnetic field (rev/min, rpm),nr = shaft
rotating speed (rev/min, rpm),When the rotor is not turning (nr=0)
then slip is 100 %)
19.The speed of an induction motor
will be same as synchronous speed when slip is
A. Infinite
B. Unity
C. Half
D. Zero
Answer : D ((s = (ns –
nr) 100% / ns,When ns = nr,Then
s=0)
20.In which motor, stator and rotor
fields rotate simultaneously
A. DC series motor
B. Universal motor
C. Slip ring induction motor
D. Synchronous motor
Answer : D
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