ELECTRICAL ENGINEERING

UPSC CSE Electrical Engineering Syllabus

UPSC Exam Syllabus- Electrical Engineering

ELECTRICAL ENGINEERING MCQs

1. According to BIS and NEC, the clearance between the bottom point of the ceiling fan and the floor shall not be less than
A:-2.5m
B:-2.75m
C:-2.25m
D:-2.4m
Ans: D

2. If firing angle in an SCR rectifier is increased, the output is
A:-remains same
B:-SCR is turned off
C:-decreased
D:-increased
Ans: C

3. Which electrode of the CRT mainly controls the brightness of the image on the screen?
A:-Anode
B:-Cathode
C:-Control grid
D:-Focusing electrodes
Ans: C

4. Efficiency of a transformer is maximum, when
A:-no load loss is equal to full load loss
B:-hysteresis loss is equal to eddy current loss
C:-copper loss is equal to eddy current loss
D:-copper loss is equal to iron loss
Ans: D

5. For the parallel operation of two transformers, the phase sequence must be identical, otherwise, during the cycle
A:-when secondaries are loaded, it will produce unequal loading conditions
B:-impossible to take the full load output without excessive heating of one of the transformer
C:-each pair of phases will be open circuited
D:-each pair of phases will be short circuited
Ans: D

6. A two layer lap wound 4 pole generator with 16 coils will have a pole pitch of
A:-32
B:-16
C:-8
D:-4
Ans: C

7. The maximum safe temperature for class F insulating material is
A:-155°C
B:-130°C
C:-120°C
D:-180°C
Ans: A

8. The ratio of intensity of magnetisation to the magnetising force is known as
A:-permeability
B:-permittivity
C:-susceptibility
D:-magnetic potential
Ans: C

9. While testing the field coil connections by compass method, the DC voltage to be applied to the field coil is
A:-10 to 20% of rated voltage
B:-the rated voltage
C:-60 to 70% of rated voltage
D:-200% of rated voltage
Ans: A

10. The relays which are capable of maintaining their contacts in the last assumed position after the power is cut off are
A:-latching relays
B:-thermal relays
C:-reed relays
D:-elctro-mechanical relays
Ans: A

11. In large motor generator sets, the AC motor used is usually
A:-squirrel cage type induction motor
B:-wound rotor type induction motor
C:-synchronous motor
D:-universal motor
Ans: C

12. A watt meter measures the
A:-Apparent power
B:-Active power
C:-Reactive power
D:-Power factor
Ans: B

13. A series resonant circuit is known as acceptor circuit, because its ______ will be maximum
A:-voltage
B:-current
C:-power factor
D:-frequency
Ans: B

14. With two watt meter method of 3 phase power measurement, if one watt meter gives negative indication, then, the power factor will be
A:-unity
B:-zero
C:-more than 0.5
D:-less than 0.5
Ans: D

15. A moving coil milliammeter having a resistance of 10 ohm gives full scale deflection, when a current of 5mA is passed through it. If the instrument to be used to measure a current up to 1A, then
A:-a resistance of 0.502 ohm must be connected in series with the ammeter
B:-a resistance of 0.502 ohm must be connected in series with the load
C:-a resistance of 0.502 ohm must be connected in parallel to the ammeter
D:-a resistance of 0.502 ohm mus be connected in parallel to the load
Ans: C

16. The instrument which give the value of quantity to be measured in terms of deflection and instrument constants are
A:-secondary instruments
B:-indicating instruments
C:-integrating instruments
D:-absolute instruments
Ans: D

17. A measuring instrument is enclosed inside an iron case. This is for protecting the measuring mechanism from
A:-heat
B:-magnetic flux
C:-static electricity
D:-hysteresis effect
Ans: B

18. The cell voltage of a Lithium cell is
A:-2.1 to 2.6V
B:-2.5 to 3.6V
C:-1.2 to 1.4 V
D:-1.5V
Ans: B

19. The illumination is directly proportional to the cosine of the angle made by the normal to the illuminated surface with the direction of the incident flux. This statement is associated with
A:-Macbeth's law of illumination
B:-Bunsen's law of illumination
C:-Lambert's cosine law
D:-Plank's law
Ans: C

20. In a drill, ______ helps to form the cutting edge.
A:-Land
B:-Shank
C:-Tang
D:-Flutes
Ans: D

21:-Recommended current density for a copper bus bar which is unenclosed should not exceed
A:-165 A/sq. cm
B:-118 A/sq. cm
C:-178 A/sq. cm
D:-135 A/sq. cm
Ans: A

22:-In which type of winding, a long coil of sufficient length is firs wound and then inserted in one slot and the reminder of the length is turned and inserted in the adjascent slots?
A:-Skein winding
B:-Involute coil winding
C:-Chain winding
D:-Basket winding
Ans: A

23:-If single phasing occurs during running of a 3 phase induction motor, then
A:-the motor may or may not run, will draw large current and the winding may burnout
B:-the motor may or may not run, will draw the normal current
C:-the motor will run normally
D:-the motor will stop
Ans: A

24:-Buchholz relay operates on
A:-oil pressure
B:-gas pressure
C:-temperature
D:-current
Ans: B

25:-The cooling oil used in a transformer should have
A:-to absorb moisture easily when exposed to air
B:-high insulation resistance
C:-low heat conductivity
D:-low firing point
Ans: B

26:-The maximum value of torque that a synchronous motor can develop with out losing its synchronism is known as
A:-breaking torque
B:-synchronising torque
C:-pull out torque
D:-pull in torque
Ans: C

27:-The transformer whose secondary is not isolated from the primary is
A:-current transformer
B:-potential transformer
C:-autotransformer
D:-step up transformer
Ans: C

28:-In the magneto-generator type insulation tester the handle is cranked at a speed of ------ rpm approximately.
A:-1000 rpm
B:-1500 rpm
C:-750 rpm
D:-160 rpm
Ans: D

29:-The light meter measures
A:-luminance
B:-luminous intensity
C:-luminous flux
D:-illuminance
Ans: D

30:-A servo voltage stabiliser provides constant voltage to an accuracy around
A:-±1% to ±0.5%
B:-0 to ±1%
C:-±0.5% to ±1.5%
D:-±1% to ±1.5%
Ans: A

31:-Submersible pumps comes under the category of
A:-centrifugal pumps
B:-jet pumps
C:-reciprocating pumps
D:-mono bloc pumps
Ans: A

32:-The size of the transformer used in battery charger depends upon
A:-charging voltage of the battery
B:-charging power of the battery
C:-charging current capacity
D:-charging energy of the battery
Ans: B

33:-According to IE rules a clear space of not less than -------- in width shall be provided in front of the switch board.
A:-91.44 cm
B:-9.144 cm
C:-91.44 mm
D:-9.144 mm
Ans: A

34:-To solder parts and terminals of medium size, the soldering iron used should be of
A:-30 W
B:-60 W
C:-80 W
D:-125 W
Ans: B

35:-The size of binding wire used for binding insulator in overhead lines should not be less than
A:-2 sq.mm
B:-1.5 sq.mm
C:-2.5 sq.mm
D:-1 sq.mm
Ans: A

36:-The fusible plug fitted on the top of the electrical geyser casing is to
A:-disconnect the electrical supply in case of short circuit
B:-release the pressure inside the tank in case of thermostat failure
C:-fuse and release the steam inside the heater in case of over heat
D:-eject the 3 pin plug to disconnect the supply in case of earth fault
Ans: B

37:-With the help of wheat stone bridge resistance in the range of -------- can be measured.
A:-0 to 1KΩ
B:-10Ω to 1MΩ
C:-100Ω to 10MΩ
D:-1Ω to 1MΩ
Ans: D

38:-The heat generated in a conductor by the flow of an electric current is proportional to the square of the current value, the resistance of the conductor and the time for which the current flows. This is stated by the law
A:-Ohm's law
B:-Joule's law
C:-Faraday's law
D:-Murphy's law
Ans: B

39:-In case of double squirrel cage induction motors, the outer cage has
A:-high resistance and low reactance
B:-high resistance and high reactance
C:-low resistance and high reactance
D:-low resistance and low reactance
Ans: A

40:-The property retentivity of material is useful on the construction of
A:-transformers
B:-electromagnets
C:-permanent magnets
D:-non magnetic substances
Ans: C

41:-The leakage flux in a transformer depends upon
A:-load current, voltage, frequency and power factor
B:-load current, voltage and frequency
C:-load current and voltage
D:-load current
Ans: D

42:-The slip rings of wound rotor machines are made from
A:-mild steel
B:-copper
C:-brass
D:-cast iron
Ans: C

43:-In large generators, Hydrogen is used as
A:-conducting medium
B:-insulating medium
C:-insulating and cooling medium
D:-conducting and cooling medium
Ans: C

44:-Highest power factor can be expected in which method of heating?
A:-Electric arc heating
B:-Dielectric heating
C:-Induction heating
D:-Resistance heating
Ans: D

45:-Sulpher hexa fluoride is used in
A:-Dynamos
B:-DC series motors
C:-Switch gears
D:-Synchronous motors
Ans: C

46:-In automobile electrical system, where alternators are used as power source, the negative terminal is earthed, because
A:-to reduce corrosion
B:-to prevent damage to rectifiers and transistors
C:-to avoid electric shock
D:-to avoid damage to alternator
Ans: B

47:-Magnetic over load relays operate faster than bi-metallic relays, becausemagnetic over load relays operate on
A:-current intensity
B:-voltage intensity
C:-thermal intensity
D:-power factor
Ans: A

48:-3 phase squirrel cage induction motors with high slip, high starting torque and relatively low starting current are comes under the class of
A:-Class D motors
B:-Class C motors
C:-Class B motors
D:-Class A motors
Ans: A

49:-Measuring instruments are classified based on their measuring accuracy. The precision and laboratory measuring devices comes under quality class of
A:-1.0
B:-0.3
C:-0.5
D:-1.5
Ans: B

50:-A triac when tested by an ohm meter will show a lower resistance in the order of 300 ohms between terminals
A:-MT 2 positive and G negative
B:-MT 1 positive and G negative
C:-MT 2 negative and G positive
D:-MT 1 positive and MT 2 negative
Ans: B

51:-_________ is the measure of how much potential difference the insulation layer can withstand without breaking down.
A:-Insulation resistance
B:-Breakdown voltage
C:-Resistance
D:-Dielectric strength
Ans: D

52:-The light output of Tin oxide Sodium lamps is in the order of
A:-50 lumens/watt
B:-45 lumens/watt
C:-75 lumens/watt
D:-150 lumens/watt
Ans: D

53:-The torque of a three phase induction motor is proportional to
A:-square root of applied voltage
B:-applied voltage
C:-square of applied voltage
D:-half of applied voltage
Ans: C

54:-Tap changing transformers are used for
A:-stepping up the voltage
B:-stepping down the voltage
C:-both stepping up and stepping down the voltage
D:-supplying low current for instruments
Ans: C

55:-Which Dc motor have negligible effect on speed with increase in torque?
A:-DC differential compound motor
B:-DC cumulative compound motor
C:-DC series motor
D:-DC shunt motor
Ans: D

56:-In a pure inductive AC circuit, the average true power is equal to
A:-V x I watts
B:-Zero watts
C:-Square of current multiplied by reactance Watts
D:-V x I volt amperes
Ans: B

57:-The part of an instrument which helps in leading in and leading out the current to the moving coil is
A:-the spindle
B:-the copper or aluminium disc
C:-jewel bearing
D:-control spring
Ans: D

58:-An outside micrometer can measure thickness and outside diameters to an accuracy of
A:-±0.1mm
B:-±0.5mm
C:-±0.001mm
D:-±0.01mm
Ans: D

59:-When a secondary battery is charged at 2% to 3% of normal rate for a long period, it is known as
A:-boost charge
B:-trickle charge
C:-freshening charge
D:-initial charge
Ans: B

60:-Double squirrel cage induction motors are used where ________ torque is essential.
A:-high starting torque
B:-low starting torque
C:-low running torque
D:-high running torque
Ans: A

61:-Which one of the following wiring circuit is not in accordance with IE rules?
A:-Corridor wiring
B:-Tunnel wiring
C:-Godown wiring
D:-Bank wiring
Ans: B

62:-The distance between the two active sides of a coil under adjacent dissimilar poles is called
A:-coil pitch
B:-winding pitch
C:-pole pitch
D:-pitch factor
Ans: A

63:-For the blocked rotor test of a 3 phase induction motor, the supply voltage should be limited to less than _______ percentage of rated voltage.
A:-5%
B:-10%
C:-3%
D:-20%
Ans: A

64:-The amount of heat required to increase the temperature of one kilogram of water through 1°C is
A:-3187 joule
B:-4187 joule
C:-4187 calorie
D:-3187 calorie
Ans: B

65:-Admittance is the reciprocal of
A:-resistancve
B:-conductance
C:-reactance
D:-impedance
Ans: D

66:-The damping winding in a synchronous motor is generally used
A:-to provide starting torque only
B:-to reduce noise level
C:-to prevent hunting and to provide the starting torque
D:-to reduce eddy currents
Ans: C

67:-Voltage dependent resistors are used as
A:-as current stabilisers
B:-as heating elements
C:-to suppress surges
D:-for inductive circuits
Ans: C

68:-In a DC generator, brush shifting is done to
A:-alter the inter pole flux
B:-alter the main field flux
C:-neutralise the cross magnetising effect
D:-neutralise the demagnetising effect
Ans: C

69:-To control a lamp from 4 positions, how many switches are required?
A:-4 two-way switcges
B:-4 intermediate switches
C:-3 two-way switches and one intermediate switch
D:-2 intermediate switches and 2 two-way switches
Ans: D

70:-The fusing factor for HRC fuse is
A:-2.0
B:-1.7
C:-1.4
D:-1.1
Ans: D

71:-Low and medium voltage underground cables should be laid at a depth of _______ from the ground surface to the top of the cable.
A:-0.75m
B:-0.9m
C:-1.0m
D:-1.05m
Ans: A

72:-For low and medium voltage overhead lines, the minimum clearance above ground, which is erected across a street, shall not be less than
A:-5.791m
B:-6.096m
C:-5.486m
D:-4.572m
Ans: A

73:-In capacitor start, capacitor run motors, the capacitors used are
A:-both capacitors are of same value
B:-one larger value capacitor of oil filled type and a smaller value capacitor of electrolytic type.
C:-one larger value capacitor of electrolytic type and a smaller value capacitor of oil filled type.
D:-both capacitors are of electrolytic type.
Ans: C

74:-While erecting a pole, the depth of pit below the ground level, in normal soil should be about _________ of the length of the pole.
A:-1/6
B:-1/5
C:-1/4
D:-1/7
Ans: A

75:-In an AC operated relay, the purpose of shading coil placed near the tip of magnetic pole face is to
A:-eliminate chatter
B:-eliminate humming
C:-to reduce eddy current
D:-to reduce hysteresis loss
Ans: A

76:-To test an armature for the short circuited coils, ________ is used along with the growler.
A:-milli-voltmeter
B:-hacksaw blade
C:-ohm meter
D:-meggar
Ans: B

77:-The type of fire extinguisher used where liquified gas is on fire is
A:-water filled fire extinguisher
B:-dry powder extinguisher
C:-foam type fire extinguisher
D:-carbon dioxide fire extinguisher
Ans: B

78:-Earthing one of the wires of electrical system, to limit the maximum voltage to earth under normal operating conditions is known as
A:-equipment earthing
B:-system earthing
C:-generator earthing
D:-substation earthing
Ans: B

79:-To measure the earth electrode resistance, the current and pressure spikes of the earth resistance tester are to be driven into the ground at a distance of ______ from the main electrode under test.
A:-20m and 10m apart respectively
B:-25m and 12.5m apart respectively
C:-20m and 10m apart respectively in a straight line
D:-25m and 12.5m apart respectively in a straight line.
Ans: D

80:-The type of joint used for overhead lines for tapping the electrical energy perpendicular to the service line is
A:-knotted tap joint
B:-aerial tap joint
C:-tee joint
D:-britannia tee joint
Ans: D

81:-Power transformers are designed to have maximum efficiency at :
A:-Half load
B:-No load
C:-Little more than full load
D:-Near full load
Ans: D

82:-1 litre of water __________.
A:-980 gm
B:-1000 gm
C:-930 gm
D:-910 gm
Ans: B

83:-Melting point of copper is __________.
A:-1230°C
B:-1085°C
C:-1088°C
D:-1083°C
Ans: D

84:-In H.S.S. 18 : 4 : 1 Means __________.
A:-Tungsten : Vanadium : Chromium
B:-Tungsten : Chromium : Vanadium
C:-Vanadium : Tungsten : Chromium
D:-Chromium : Vanadium : Tungsten
Ans: B

85:-Which colour wire is recommended for earth connection as per ISI Code ?
A:-Red
B:-Black
C:-Blue
D:-Green
Ans: D

86:-What is the value of cos 0° ?
A:-1
B:-0
C:-√2
D:-√3
Ans: A

87:-On which factors the frequency depends ?
A:-Directly proportional to speed and no. of poles
B:-Inversely proportional to speed and no. of poles
C:-Directly proportional to back emf
D:-Directly proportional to applied voltage and back emf
Ans: A

88:-What is the complete formula for frequency ?
A:-`F=(PxxN)/(60)`
B:-`F=(Ns-N)/(60)`
C:-`F=` `(PxxE)/(120)`
D:-`F=``(PxxNS)/(120)`
Ans: D

89:-Where the Damper winding is placed in synchronous motor ?
A:-Shaft
B:-Poles
C:-Poleshoes
D:-All of the above
Ans: C

90:-Capacity of a capcitor filled in table fan or ceiling fan :
A:-1 to 1.5 µf
B:-3 to 3.5 µf
C:-2.5 to 3 µf
D:-2 to 2.5 µf
Ans: D

91:-How the current coils and pressure coils are connected in megger ?
A:-At 90° to each other
B:-At 60° to each other
C:-At 45° to each other
D:-At 35° to each other
Ans: A

92:-Supertension cables from :
A:-33000 Volt to 66000 Volt
B:-1000 Volt 11000 Volt
C:-11000 Volt to 22000 Volt
D:-22000 Volt to 33000 Volt
Ans: D

93:-The distance between two adjacent line poles is called :
A:-Sag
B:-Span
C:-HSL
D:-Guarding
Ans: B

94:-The distance that must be provided between line conductors for 440 V :
A:-50 cm - 60 cm
B:-45 cm - 60 cm
C:-45 cm - 50 cm
D:-30 cm - 45 cm
Ans: D

95:-Rotary converter runs at :
A:-Below synchronous speed
B:-Synchronous speed
C:-Above synchronous speed
D:-All of the above
Ans: B

96:-A series RL circuit has a resistance of 30 Ω and inductive resistance of 40 Ω. The impedance is __________.
A:-70 Ω
B:-50 Ω
C:-10 Ω
D:-35 Ω
Ans: B

97:-The magnetic field produced in the stator of a three phase induction motor rotates at __________.
A:-Rotating speed
B:-Synchronous speed
C:-Asynchronous speed
D:-Slip speed
Ans: B

98:-The meter used to measure the temperature of furnace is :
A:-Hydrometer
B:-Hygrometer
C:-Pyrometer
D:-Tachometer
Ans: C

99:-The conduction in a JFET is always by the :
A:-Minority carriers
B:-Majority carriers
C:-Holes
D:-Electrons
Ans: B

100:-FET is :
A:-Unipolar device
B:-Bipolar device
C:-Half Power device
D:-All of the above
Ans: A