1. The Elecrochemical reactions are not reversible in case of,
a. Primary b. Secondary c. Both Primary and secondary d. None
2. Negetive terminal of dry cell is made of,
a. Carbon b. Zinc c. Lead d. None
3. The purpose of AC is to produce heat, Conductor are selected on the basis of,
a. Peak Value of Current b. Average value of current c. RMS value of current d. Any of above
4. PIV of AC is
a. 1.414 b. 0.7 c. d.
5. Ohms Law for magnetic circuit can be stated as,
a. MMF=Flux x Reluctance
6. A unit impulse function is obtained on the differentiation of,
a. A unit ramp function b. A unit Step function c. A unit triplet d. A unit doublet
7. Transfer function is in
a. time domain b. Frequency domain c. d.
8. Which variety of copper has best conductivity,
a. Pure annealed copper b. Hard drawn copper c. Induction hardened copper d. Copper containing traces of silicon
9. The electrical breakdown strength of a material depends upon,
a. Composition b. Thickness c. Moisture Content d. All of above
10. Which of the following is used for cable insulation,
a. Cross link XEP or PVC b. same c. same d. All of the above
11. Which of the following has maximum electrical conductivity,
a. Lead b. Copper c. Aluminium d. Stainless steel
12. Which of the following gaseous insulating material has highest electrical strength,
a. Air b. Hydrogen c. Carbon dioxide d. Sulphur hexaflouride
13. Breakdown in dielectric may be,
a. Electrical breakdown b. Thermal breakdown c. Elecrochemical breakdown d. All of above
14. Which one is correct,
a. E= -DelxV b. E= Del.V c. Del = E x V d. Del = E.V
15. Inside a hollow spherical conductor Electric field is,
a. Constant b. Zero c. Changes with magnitude of charge given to conductor d. changes with distance from center of sphere
16. The Uniform electric field field lines and equipotentials,
a. Zero b. Infinity c. Orthognal d. Parallel
17. Whenever a conductor cuts magnetic flux an emf is induced in that conductor. Above statement is due to,
a. Faraday's Law b. Joules Law c. Coulombs Law d. Gravitional Law
18. Coulumbs law is the same as ,
a. Faraday's Law b. Joules Law c. Coulombs Law d. Gravitional Law
19. In case of lightening struck which of the following are used,
a. Low Foot resisitor for tower b. Surge arrestor c. d. All of the above
20. IC Opam has
a. 1 input b. 1 output c. 2 inputs 1 output d. 1 input 2 outputs
21. For Signed Binary numbers which one is used,
a. 1's complement b. 2's complement c. d.
22. for MAX terms which two gates are used,
a. ANR-OR b. OR-AND c. NAND-OR d. XOR-NAND
23. For Highly capacitive circuit,
a. Active power=Apparent power b. Apparent power=Reactive power c. Apparent power>Active power d. Active power >Apparent power
24. Output of RS flip is
25. Output of JK flip flop is
26. Which of the following is true,
a,b,c Lithium cells are used in clocks and are non rechargeble d.
27. Output of Class A amplifer is
a. Distorted b. Same as output c. d.
28. A triac is a semiconductor device which acts a
a. 2 terminal unidirectional switch
b. 2 terminal bidirectional switch
c. 3 terminal bidirectional switch
d. 4 terminal multidirectional switch
29. For parallel operation the genrators are normally prefered as,
a. Series Generator b. Shunt Generator c. Compound Generator d. Series and Shunt genrator
30. Hysteresis losses in a dc machine depends on,
a. Voulume and grade of iron b. maximum flux density c. frequency of magnetic reversals d. All of above
31. Which of the following has highest proportion in DC machines
a. Armature copper losses b. field copper losses c. Hysteresis losses d. Eddy current losses
32. Hysteresis losses varies as,
a. directly flux density b. invesrsly flux density c. d.
33. which of the following is minimised by laminating the core of a transformer,
a. Hysteresis losses b. Eddy current losses c. Heat losses d. Any of above
34. For a transformer the condition of maximum efficiency is,
a. Hysteresis loses=eddy current losses
b. Core losses=Hystersis loses
c. Copper losses = iron losses
d. total losses =2/3 copper losses
35. Eddy current losses in a T/F can be reduced by,
a. reducing the thickness of lamination
b. increasing the thickness of laminations
c. increasing the air gap in magnetic field
d. reducing the air gap in magnetic field
36. A short circuit test on T/F gives,
a. Copper losses at full load.
b. Copper losses at half load.
c. iron losses at any load.
d. Sum of copper and iron losses.
37. PU impedance of the T/F is,
a. greater than the primary side
b. Less than the secondary side
c. Primary and seconday impedance is same
d. None of the above
38. Polar dielectrics are normally used for,
a. High frequencies b. Microwaves c. DC and power fequencies d. None of the above
39. Switching surge is
a. High voltage AC b. High voltage DC c. Short duration transient voltage d. hyperbollically dying volatage.
40. Impulse testing of a T/F is done to,
a. Bushings to withstand vibrations b. Insulation to withstand transient voltages c. windings to withstand voltage fluctuations d. All of above
41. Impulse voltages are characterized by,
a. Peak Value b. Polarity c. time of half the peak value d. All of above
42. Paschen's law is associated with,
a. Ionization b. Breakdown voltage c. Thermal radiations d. None of above
43. frequency of 60 hz full wave rectifier is
a. 30Hz b. 60Hz c. 120Hz d. 0
44. Damping torque in instruments is genrally produced,
a. Pneuamatically b. Electromagnetically c. Electrostatically d. by fluid reaction
45. The pointer of instrument once deflected returns to zero position when the current is removed due to,
a. Action of gravity b. Mass of pointer c. Controlling torque d. Damping torque
46. The deflecting torque in instrument is produced,
a. Magnetically b. Electrostatically c. Thermally d. Any of the above
47. A bridge used to measure the dielectric loss of an insulator is,
a. Anderson's bridge b. Wien's bridge c. Schearing bridge d. Any of above
48. The thyristor is turned off when the anode current falls below the,
a. Forward current b. Latching current c. Holding current d. Breakover current
49. In thyristor angle of conduction is changed by
a. Anode voltage b. gate current c. forward current d. anode current
50. in thyristor dv/dt protection is achieved through the use of
a.L accross thyristor b. R accross thyristor c. RC accross thyristor d. RL accross thyristor
51. in thyristor di/dt protection is achieved through the use of
a. L in series with thyristor b. R in series with thyristor c. RC in series with thyristor d. RL in series with thyristor
52. Output waveform of signal can be seen on
a. function genrator b. Oscilloscope c. d.
53. flip flop is used in
a)counter b)register c) memory d) all right choice
54. hoe many nand gates are used for or gate right
a. 3 b. 4 c.5 d. 5
55. when load on isolated generator increases and power to the prime mover is cut off
a) generator slow down b. Genratot speed up c. d.
56. rectifier convert ac in pulsating dc
57. How many diodes conduct during half cycle of bridge rectifier?
a. 1 b. 2 c. 3 d. 4
58. Universal gate is
a. AND gate b. OR gate c. NAND gate d. XOR gate
59 D-flip flop is ???