Electrician Theory Solved Paper ||Semester 2nd // Paper-1st // NCVT Exam July 2019||

1. Which instrument provides a visual representation of measured or tested quantities ? 

(A) Voltage stabilizer 

(B) Function generator 

(C) Cathode ray oscilloscope 

(D) Radio frequency generator 
Answer -(C)

2. Which device is made up of using the methods of point contact, grown , diffusion and alloy junctions ? 

(A) Inductor 

(B) Resistor 

(C) Capacitor 

(D) Transistor 

Answer -(D)

3. Why the collector region is physically made larger than emitter region in a transistor ? 

(A) It has to dissipate more heat 

(B) Output taken from collector terminal 

(C) Base collector region is reverse biased . 

(D) Collector region always operate with high voltage

Answer -(A) 

4. What is the function of a transistor if emmiter to base and collector to base are forward biased ? 

(A) Acts as an amplifier
(B) Acts as an oscillator
(C) Acts as an open circuit
(D) Acts as a closed circuit

 Answer -(D) 

5. What is the name of amplifier circuit ? 

(A) Common base amplifier 

(B) Common emitter amplifier 

(C) Class B push pull amplifier

(D) Common collector amplifier

Answer -(D)

6 What is the main advantage of a class A amplifier ? 

(A) Minimum distortion 

(B) Maximum current gain 

(C) Maximum voltage gain 

(D) Minimum signal to noise ratio losses

Answer -(A)

7. What is the name of amplifier ? 

(A) Common emitter amplifier 

(B) Class B push pull amplifier 

(C) Common collector amplifier 

(D) Class AB push pull amplifier 

Answer -(B)

8.Which electronic circuit produces signal wave or pulses without an input ? 

(A) Detector 

(B) Amplifier 

(C) Oscillator 

(D) Modulator

Answer -(C) 

9. Which circuit is essential to maintain oscillations or waves in an oscillator circuit ?

(A) Rectifier with filter

(B) Voltage muliplier

(C) Negative feedback

(D) Positive feed back 

Answer -(D)

10. What is the formula to calculate the resonance frequency in an oscillator circuit ?

(A) Fr=1/2 πLC

(B) Fr=1/√2 πLC

(C) Fr =1/2 π√LC

(D) Fr=1/LC√2 π

Answer -(C) 

11. What is the main application of unijunction transistor ?

(A) Rectification

(B) Amplification

(C) Regulator circuits

(D) Triggering circuits

Answer -(D) 

12. Which device has very high input impedance, low noise output, good linearity and low inter electrode capacity ?

(A) NPN transistor

(B) PNP transistor

(C) Field effect transistor

(D) Unijunction transistor

Answer -(C) 

13. What is the difference in current control of MOSFET compared to JFETs ?

(A) Insulating layer instead of junction

(B) Using N material instead of P material

(C) Using P material instead of N material

(D) Using N material gate instead of P material

Answer -(A) 

14. Which wiring is suitable for temporary installations? 

(A) Cleat wiring

(B) Concealed wiring

(C) PVC conduit wiring

(D) Metal conduit wiring

Answer -(A)

15. Where the phase conductor is looped in looping system of wiring? 

(A) Switch box

(B) Junction box

(C) Distribution box

(D) Socket connection

Answer -(D) 

16. How many link clips are packed in cardboard boxes as per BIS rules? 

(A) 50 clips

(B) 75 clips

(C) 100 clips

(D) 150 clips

Answer -(C) 

17. What is the application of the wiring circuit?  

(A) Two lamps dim operation only

(B) Two lamps controlled by one switch

(C) Two lamps controlled by two switches

(D) One lamp bright and two lamp dim operation

Answer -(D) 

18. How the conduit pipe size is specified? 

(A) Length of pipe

(B) Thickness of pipe

(C) Inner diameter of pipe

(D) Outer diameter of pipe

Answer -(D) 

19. What is the reason for home theater wiring not to run along with power wiring? 

(A) Avoid leakage current in home theater wiring

(B) Control temperature in home theater wiring

(C) Avoid electrical interference in audio, video system

(D) Reduce the power consumption in power supplies

Answer -(C) 

20. Which instrument is used to measure insulation resistance in wiring installation? 

(A) Megger

(B) Multimeter

(C) Shunt type ohmmeter

(D) Series type ohmmeter

Answer -(A) 

21. Which rule is used to find direction of dynamically induced emf? 

(A) Cork screw rule

(B) Right hand palm rule

(C) Fleming's left hand rule

(D) Fleming's right hand rule

Answer -(D) 

22 What is the name of the part of DC motor ?  

(A) Stator

(B) Pole core

(C) Pole shoes

(D) Yoke (or) frame

Answer -(A) 

23. Which metal is used to make pole core of large DC generator machines? 

(A) Soft iron

(B) Cast iron

(C) Cast steel

(D) Stainless steel

Answer -(C) 

24. How many parallel paths in duplex lap winding of a 4 pole DC generator? 

(A) 4

(C) 8

(D) 12

(B) 6

Answer -(C) 

25. Why the armature cores are laminated in DC generator? 

(A) Reduce the friction loss

(B) Reduce the windage loss

(C) Reduce the hysteresis loss

(D) Reduce the eddy current loss

Answer -(B) 

26. Which type of DC generator is used for electroplating process? 

(A) Shunt generator

(B) Series generator

(C) Differential compound generator

(D) Cumulative compound generator

Answer -(A) 

27.  Name the part of DC generator?

(A) Side end plates

(B) Pole shoe lamination

(C) Commutator segment

(D) Armature core lamination 
Answer -(D) 
 

28. Which rule is applied to identify the direction of rotation of conductor in DC motor? 

(A) Cork's screw rule

(B) Right hand grip rule

(C) Fleming’s left hand rule

(D) Fleming’s right hand rule

Answer -(C) 

29. What is the purpose of compensating winding in DC generator? 

(A) Minimizes rough commutation

(B) Maintain constant output voltage

(C) Neutralizes the demagnetizing effect

(D) Decreases the excitation current of field coils

Answer -(C) 

30. What is the effect on induced emf if the main field flux get distorted in DC generator?

(A) Induced EMF increases

(B) Induced EMF decreases

(C) No change in induced EMF

(D) Induced EMF becomes zero

Answer -(B)

31. Name the type of DC motor.  

(A) Shunt motor

(B) Series motor

(C) Long shunt compound motor

(D) Short shunt compound motor

Answer -(D) 

32. What is the best method to change the DOR of a compound motor without change of its characteristics? 

(A) Change armature current direction

(B) Change shunt field current direction

(C) Change series field current direction

(D) Change the current in armature and shunt field together

Answer -(A) 

33. What is the necessity of starter in DC motor? 

(A) To improve the torque

(B) Reduce the field current

(C) To decrease the back EMF

(D) Reduce the armature current

Answer -(D) 

34. What is the formula to calculate back EMF in a DC motor? 

(A) Eb=ZNP/Ø60A

(B) Eb=NP/ØZ60A

(C) Eb=ØZNP/60A

(D) Eb= 60AØ/ZNP

Answer -(C) 

35. Which type of DC motor is used for sudden application of heavy loads? 

(A) Shunt motor

(B) Series motor

(C) Differential compound motors

(D) Cumulative compound motors

Answer -(D) 

36. Which speed control method is used in food mixture motors? 

(A)Voltage control method

(B) Field diverter control method

(C) Armature diverter method

(D) Series field tapping method

Answer -(D) 

37. Which speed control system provides a smooth variation of speed from zero to above normal? 

(A) Field control

(B) Armature control

(C) Field diverter control

(D) Ward - Leonard system control

Answer -(D) 

38. What is the advantage of stepped core arrangement in larger transformers? 

(A) Minimizes copper use

(B) Reduces hysteresis loss

(C) Reduces eddy current loss

(D) Reduces the space for core

Answer -(A) 

39. Which material is used in breather to prevent moisture entering in the transformer oil? 

(A) Silica gel

(B) Sodium chloride

(C) Ammonium chloride

(D) Charcoal and salt mixture

Answer -(A) 

40. What is the disadvantage of auto transformer? 

(A) More losses

(B) Heavier in weight

(C) Poor voltage regulation

(D) Cannot isolate the secondary winding

Answer -(D) 

41. Which cooling method is used in pole mounting distribution transformer? 

(A) Air natural

(B) Oil natural air blast

(C) Oil forced air forced

(D) Oil natural air natural

Answer -(D) 

42. What is the composition of steel and silicon steel in transformer core? 

(A) Steel 97% and silicon 3%

(B) Steel 95% and silicon 5%

(C) Steel 93% and silicon 7%

(D) Steel 90% and silicon 10%

Answer -(C) 

43. What is the purpose of tap changing in power transformers? 

(A) Maintain primary voltage constant

(B) Change voltage ratio in distribution

(C) Maintain secondary voltage constant

(D) Load the transformer for maximum efficiency

Answer -(B) 

44.  What is the name of meter?  

(A) Multi range DC ammeter

(B) Multi range DC voltmeter

(C) Single range AC ammeter

(D) Single range AC voltmeter

Answer -(B) 

45. What is the name of the instrument? 

(A) Absolute instrument

(B) Indicating instrument

(C) Recording instrument

(D) Integrating instrument

Answer -(A) 

46. Why damping force is required in a moving coil instrument? 

(A) Makes the needle movement faster

(B) Helps the deflecting force to act fast

(C) Brings the needle to its zero position

(D) Arrests the needle without oscillations

Answer -(D) 

47. What is the function of suft iron core in a moving coil instrument?  
(A) Strengthens the deflection force

(B) Controls the needle's movement

(C) Provides meter with maximum sensitivity

(D) Provide uniform distribution of magnetic flux in air gap

Answer -(D) 

48. Which parameter is the cause for loading effect on measuring instruments? 

(A) Low accuracy

(B) High sensitivity

(C) Low sensitivity

(D) Low influence error

Answer -(C) 

49.  Name the type of instrument.  

(A) Attraction type moving iron

(B) Repulsion type moving iron

(C) Permanent magnet moving coil

(D) Dynamo meter type moving coil

Answer -(A) 

50. Which meter is used to measure revolution per minute of a motor?  
(A) Tachometer

(B) Energy meter

(C) Ampere hour meter

(D) Center zero ammeter

Answer -(A)