KPSC-Instructor Grade I-079/2017 Answer key

#1. The all day efficiency of transformer depends on……?

copper loss

amount of load

duration of load

both B and C

#2. A 3 phase induction motor is running at a slip of 4% and input to the rotor is 2000watts. the mechanical power developed in the rotor is….?

1920 W

2000 W

1000 W

800 W

#3. If the stator frequency and voltage of an induction motor are reduced proportionally, then…..?

locked rotor current is reduced

torque developed is increased

magnetising current is decreased

both A and B

#4. In a squirrel cage induction motor, the starting torque with auto transformer starting is…..times the torque with direct switching, K being the transformation ratio of the auto transformer.

K2

1/K

K

1/K2

#5. The power factor of an alternator under short conditions is…..?

unity

almost zero lagging

almost zero leading

none of these

#6. What is the address(SFR) for TCON, SCON, SBUF, PCON, and PSW respectively?

88H, 98H, 99H, 87H, 0D0H

98H, 99H, 87H, 88H, 0D0H

ODOH, 98H, 87H, 88H,

87H, 88H, ODOH, 98H, 99H

#7. A thyrite type lightning arrestor….?

blocks the surge voltage appearing in a line

absorbs the surge voltage appearing in a line

offers a low resistance path to the surge

returns the surge back to the source

#8. Which of the following types of heating will be preferred for cooking food without removing the outer shells?

direct resistance heating

indirect heating

dielectric heating

electric arc heating

#9. Damping used in moving iron instrument is…..?

air friction

eddy current

fluid friction

none of these

#10. An RLC series circuit remains predominatly inductive…..?

at resonant frequency

below resonant frequency

above resonant frequency

at lower half power frequency

#11. In a single phase full wave rectifier, during blocking state the peak inverse voltage of diode is Vm is the peak voltage?

Vm

2Vm

Vm/2

v2Vm

#12. A forward voltage can be applied to SCR after its…..?

anode current reduce to zero

gate recovery time

anode voltage reduces to zero

reverse recovery time

#13. Synchronous motor is normally used for driving…..

cranes

lathes

fans

rotating compressors

#14. In moving iron instrument, the deflecting torque is proportional to……

I2

I

1/I2

none of these

#15. An ohmmeter is a ……

moving iron instrument

moving coil instrument

dynamometer instrument

none of these

#16. In a single phase power factor meter, the phase difference between the currents in the two pressure coils is….

exactly zero

approximately zero degree

exactly 90

approximately 90

#17. In PLC Ladder logic programming consists of….

logic gate symbols and connecting lines

virtual relay contacts and coils

function blocks and connecting lines

text based codes

#18. Transmissiom lines are transposed to…..?

reduce copper loss

reduce skin effect

prevent interference with neighbouring telephone lines

prevent short circuit between any two lines

#19. The use of zener diode connected in a UJT circuit used for triggering an SCR is to….?

delay the generation of triggering pulse

speed up the generation of triggering pulse

supply constant voltage to UJT for correct firing

supply a variable voltage to UJT as source voltage varies

#20. The input impedence of a CRO is…..?

zero

around 100 ohms

around 1 kilo ohms

around 1 mega ohms

#21. A mirror is placed behind the pointer in measuring instruments for……?

with the help of the mirror it may be seen whether the pointer is bent or not

the scale is illuminated through the mirror

reading errors due to inclined observation are eliminated by removing parallax between the pointer and its image in the mirror

none of these

#22. For proper earthing, the earth wire should not be of size smaller than…..?

10 SWG copper

8 SWG copper

6 SWG copper

4 SWG copper

#23. The most economical DC distribution system is…..?

inter connected system

radial system

ring system

none of these

#24. The coil span of dc armature winding is made equal to pole switch in order to….

distribute the windings uniformly under different poles

obtain a coil span of 180 electrical

ensure the addition of emfs of consecutive turns

obtain a full pitch winding

#25. Which of the following type of generators does not require equalizers for satisfactorily for parallel operation?

series

under compound

over compound

flat compond

#26. In a dc motor, unidirectional torque is produced with the help of…..

brushes

commutator

end plates

both A and B

#27. The torque Vs armature current graph for a dc series motor is….

parabola from no load to over load

straight line

parabola upto full load and straight lines at over loads

rectangular hyperbola

#28. A 200 KVA transformer has iron lossof 1KW and full load copper loss of 2 KW.the KVA corresponding to maximum efficiency is……

200 KVA

141.1 KVA

100 KVA

50 KVA

#29. In a synchronous machine, the angle between the synchronously rotating stator flux and rotor poles is called…..?

synchronizing angle

torque angle

load angle

slip angle

#30. A 100V/20V , 100 VA transformer is converted to 100V/110V auto transformer the rating of the auto transformer is….

100 VA

110 VA

500 VA

550 VA

#31. If the mechanical load of a three phase induction motor is increased from no load to full load, the input power factor of the motor will ….

remains same

decreases

increases

becomes unity

#32. In which of the region, induction motor operation is stable?

low slip region

high slip region

both A and B

none of these

#33. Grading of cables is done to achieve…..

to reduce quality of insulation

uniform stress

improve efficiency

all of the above

#34. Steady state stability of a power system is enhanced by……

reducing the fault clearing time

using double circuit lines

single pole switching

decreasing the generator inertia

#35. A hydel power plant of run off river type should be provided with a pondage so that…..

firm capacity of plant is increased

operating head is controlled

pressure inside the turbine remains constant

kinetic energy of running water is fully utilized

#36. Which one is not a unconventional source of energy?

tidal power

geothermal energy

fossil fuel

wind power

#37. The pin which provides reset option in 8051 micro controller is…..

pin 1

pin 9

pin 11

pin 8

#38. In sodium vapour lamp, neon gas….

acts as a shield around the filament

assists in developing enough heat to vaporize the sodium

change the colour of light

prevents the vaporization of filament

#39. Corona loss increases with…..

increase in supply frequency and conductor size

increase in supply frequency but reduction in conductor size

decrease in supply frequency and conductor size

decrease in supply frequency but increase in conductor size

#40. If the excitation of a synchronous generator fails, it acts as a……

synchronous motor

synchronous generator

induction generator

induction motor

#41. The device that does not have the gate terminal is….

Triac

FET

SCR

Diac

#42. A string insulator has 5 units. The voltage across the bottom most unit is 25% of the total voltage. string efficiency is…..?

25 %

50 %

80 %

75 %

#43. Resistance switching is normally employed in the case of…..?

Bulk oil CB

Minimum oil CB

Air blast CB

All of the above

#44. Electric power for steam locomotive is provided through…..?

over head wire

battery system

small turbo generator

diesel engine generator

#45. The vertical core type induction furnace requires supply at…..?

normal frequency

high frequency

very low frequency

independent of frequency

#46. Pin type insulators are mainly used in…..?

distribution system

transmission system

transmission and distribution system

EHV transmission system

#47. The 8051 uses which RAM locations for register R0-R7 on powering up….?

00-2F

00-07

00-7F

00-0F

#48. An isolated device used to protect a PLC from incoming surge from fields…..?

transformer

transducer

LVDT

thermocouple

#49. Fusing factor is defined as the ratio between….?

maximum fusing current and rated voltage

maximum fusing current and rated current

minimum fusing current and rated current

minimum fusing current and rated voltage

#50. 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, statement is associated with…..?

planck's law

macbeth's law of illumination

bunsen's law of illumination

Lambert's cosine law

#51. If the current in a zero resistance wire AB is increased, the voltage Vab across the wire will…..

decreases

increases

remain constant

none of these

#52. Cutting an air gap in a magnetic circuit result in….?

reduction of reluctance

increase in reluctance

no change in reluctance

none of these

#53. In a parallel RC circuit….

Ic lags Ir by 90

Ic leads Ir by 90

Ic and Ir are in phase

Ic lags Ir by 60

#54. A 1000W, 230 V electric kettle is connected in series with another similar kettle and the combination is connected to 230V supply. The total power drawn by the combination will be…..?

1000 W

less than 1000 W

more than 1000 W

zero

#55. The unit of the permittivity is…..?

farad/meter

farad - meter

farad / meter 2

none of these

#56. Load impedence must match amplifier output impedence in order that……?

minimum power transferred to the load

maximum power transferred to the load

collector circuit efficiency is highest

signal to noise ratio is maximum

#57. Astable multi vibrator may be used as…..?

frequency to voltage converter

voltage to frequency converter

squaring circuit

comparator circuit

#58. Which of the following logic gate dissipates minimum power?

RTL

TTL

MOS

ECL

#59. The 2’s complement of binary number 0.01011 is……

1.10101

0.10101

0.10100

1.10100

#60. Universal gates are…?

NOR

AND

NAND

Both A and C

#61. In a full wave rectifier, the peak inverse voltage per diode is….?

Vm

Vm / 2

2Vm

(2VM)1/2

#62. What is CDMA?

Code diversified multiple access

Code division multiple access

Code divergence multiplex access

Code direction multiple access

#63. Octal equivalent of decimal 51 is….?

63

41

67

69

#64. In a T flip flop, ratio of frequency of the input pulse to the frequency of out put pulse is….?

1/2

1

2

3

#65. The transistor amplifier stage has lowest input impedance in….?

CB

CC

CE

Same in all configurations

#66. The function of a filter in a rectifier is to….?

limit the total current in the rectifier

limit the peak voltage of the rectifier

limit the DC current

reduce the ripple voltage in the output

#67. Register that is used to hold the memory address of the next instruction to be executed….?

program memory

program counter

control unit

instruction decoder

KPSC-Instructor Grade I-079/2017 Answer key

#1. The all day efficiency of transformer depends on……?

#2. A 3 phase induction motor is running at a slip of 4% and input to the rotor is 2000watts. the mechanical power developed in the rotor is….?

#3. If the stator frequency and voltage of an induction motor are reduced proportionally, then…..?

#4. In a squirrel cage induction motor, the starting torque with auto transformer starting is…..times the torque with direct switching, K being the transformation ratio of the auto transformer.

#5. The power factor of an alternator under short conditions is…..?

#6. What is the address(SFR) for TCON, SCON, SBUF, PCON, and PSW respectively?

#7. A thyrite type lightning arrestor….?

#8. Which of the following types of heating will be preferred for cooking food without removing the outer shells?

#9. Damping used in moving iron instrument is…..?

#10. An RLC series circuit remains predominatly inductive…..?

#11. In a single phase full wave rectifier, during blocking state the peak inverse voltage of diode is Vm is the peak voltage?

#12. A forward voltage can be applied to SCR after its…..?

#13. Synchronous motor is normally used for driving…..

#14. In moving iron instrument, the deflecting torque is proportional to……

#15. An ohmmeter is a ……

#16. In a single phase power factor meter, the phase difference between the currents in the two pressure coils is….

#17. In PLC Ladder logic programming consists of….

#18. Transmissiom lines are transposed to…..?

#19. The use of zener diode connected in a UJT circuit used for triggering an SCR is to….?

#20. The input impedence of a CRO is…..?

#21. A mirror is placed behind the pointer in measuring instruments for……?

#22. For proper earthing, the earth wire should not be of size smaller than…..?

#23. The most economical DC distribution system is…..?

#24. The coil span of dc armature winding is made equal to pole switch in order to….

#25. Which of the following type of generators does not require equalizers for satisfactorily for parallel operation?

#26. In a dc motor, unidirectional torque is produced with the help of…..

#27. The torque Vs armature current graph for a dc series motor is….

#28. A 200 KVA transformer has iron lossof 1KW and full load copper loss of 2 KW.the KVA corresponding to maximum efficiency is……

#29. In a synchronous machine, the angle between the synchronously rotating stator flux and rotor poles is called…..?

#30. A 100V/20V , 100 VA transformer is converted to 100V/110V auto transformer the rating of the auto transformer is….

#31. If the mechanical load of a three phase induction motor is increased from no load to full load, the input power factor of the motor will ….

#32. In which of the region, induction motor operation is stable?

#33. Grading of cables is done to achieve…..

#34. Steady state stability of a power system is enhanced by……

#35. A hydel power plant of run off river type should be provided with a pondage so that…..

#36. Which one is not a unconventional source of energy?

#37. The pin which provides reset option in 8051 micro controller is…..

#38. In sodium vapour lamp, neon gas….

#39. Corona loss increases with…..

#40. If the excitation of a synchronous generator fails, it acts as a……

#41. The device that does not have the gate terminal is….

#42. A string insulator has 5 units. The voltage across the bottom most unit is 25% of the total voltage. string efficiency is…..?

#43. Resistance switching is normally employed in the case of…..?

#44. Electric power for steam locomotive is provided through…..?

#45. The vertical core type induction furnace requires supply at…..?

#46. Pin type insulators are mainly used in…..?

#47. The 8051 uses which RAM locations for register R0-R7 on powering up….?

#48. An isolated device used to protect a PLC from incoming surge from fields…..?

#49. Fusing factor is defined as the ratio between….?

#50. 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, statement is associated with…..?

#51. If the current in a zero resistance wire AB is increased, the voltage Vab across the wire will…..

#52. Cutting an air gap in a magnetic circuit result in….?

#53. In a parallel RC circuit….

#54. A 1000W, 230 V electric kettle is connected in series with another similar kettle and the combination is connected to 230V supply. The total power drawn by the combination will be…..?

#55. The unit of the permittivity is…..?

#56. Load impedence must match amplifier output impedence in order that……?

#57. Astable multi vibrator may be used as…..?

#58. Which of the following logic gate dissipates minimum power?

#59. The 2’s complement of binary number 0.01011 is……

#60. Universal gates are…?

#61. In a full wave rectifier, the peak inverse voltage per diode is….?

#62. What is CDMA?

#63. Octal equivalent of decimal 51 is….?

#64. In a T flip flop, ratio of frequency of the input pulse to the frequency of out put pulse is….?

#65. The transistor amplifier stage has lowest input impedance in….?

#66. The function of a filter in a rectifier is to….?

#67. Register that is used to hold the memory address of the next instruction to be executed….?

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