electrical engineering Mcqs
1. economics of power generation2. analog electronics3. solid state switching circuits4. parallel circuits5. switchgear and protection6. op amp circuits7. transistor audio power amplifiers8. electrostatics9. heating and welding10. multi stage transistor amplifiers11. passive filters12. network theorems13. regulated d c power supply14. a c fundamentals circuits and circuit theory15. electromagnetic induction16. power electronics17. magnetism and electromagnetism18. transformers19. modulation and demodulation20. d c generators21. semiconductor theory22. single phase induction motors23. semiconductor diode24. hybrid parameters25. digital electronics26. oscillators27. earthing or grounding28. single stage transistor amplifiers29. d c motors30. transistor biasing31. amplifiers with negative feedback32. basic electrical33. electronic instruments34. synchronous motors35. field effect transistors fet36. magnetic circuit37. control systems38. industrial drives39. power generation40. series parallel circuits41. transistor tuned amplifiers42. electrical engineering materials43. rectifiers and converters44. integrated circuits45. scr silicon controlled rectifiers46. cables47. polyphase induction motors48. measurement and instrumentation49. transistors50. electrical machine design51. electrolysis and storage of batteries52. electric traction53. transmission and distribution
5401. If a particular application needs high speed and high starting torque, then which of the following motor will be preferred ?
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A. Shaded pole type motor

B. Capacitor start and run motor

C. Capacitor start motor

D. Universal motor
5402. Which of the following single-phase motors has relatively poor starting torque ?
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A. Universal motor

B. All single phase motors have zero starting torque

C. Repulsion motor

D. Capacitor motor
5403. Speed control of a universal motor is achieved by__________?
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A. all of the above methods

B. applying variable voltage by means of silicon controlled rectifier

C. applying variable voltage by means of variable auto-transformer

D. connecting rheostat in series

E. varying field flux with tapped field windings

5404. Which of the following single-phase induction motors is generally used in time phonographs ?
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A. Resistance start

B. Capacitor start capacitor run

C. Shaded pole

D. Universal

5405. In a A.C. series motor armature coils are usually connected to commutator____________?
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A. solidly

B. through capacitors

C. through reactances

D. through resistance
5406. A universal motor can run on___________?
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A. A.C. only

B. either A.C. or D.C.

C. D.C. only

D. none of the above

5407. Which of the following statements regarding reluctance-start motor is incorrect ?
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A. So far as its basic working principle is concerned, it is similar to shaded pole motor

B. It is basically an induction motor and not a synchronous one

C. It is similar to reluctance motor

D. the air-gap between rotor and salient poles is non- uniform

5408. Torque developed by a single phase induction motor at starting is_____________?
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A. uniform

B. pulsating

C. nil

D. none of the above

5409. In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will_____________?
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A. draw excessive armature current and may burn out

B. fall out of synchronism and come to stand still

C. run as induction motor

D. become unstable

5410. In case of high speed universal motor which of the following needs more attention?
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A. End play

B. Air gap

C. Insulation in rotor

D. Balancing of rotor
5411. Which of the following motors is used in mixies ?
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A. Repulsion motor

B. Hysteresis motor

C. Reluctance motor

D. Universal motor
5412. Direction of rotation of a split phase motor can be reversed by reversing the connection of__________?
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A. running winding only

B. starting winding only

C. either A. or (b)

D. both A. and (b)

5413. The value of starting capacitor of a fractional horse power motor will be__________?
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A. 300 uF

B. 200 uF

C. 400 uF

D. 100 uF

5414. In a hysteresis motor, the rotor must have____________?
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A. none of the above

B. susceptibility

C. retentivity

D. resistivity

5415. A repulsion motor is equipped with__________?
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A. slip rings

B. commutator

C. both A. and (b)

D. none of the above

5416. The reverse current in a diode is of the order of _____________?
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A. mA

B. ?A

C. A

D. kA

5417. The doping level in a zener diode is______________ that of a crystal diode?
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A. more than

B. the same as

C. less than

D. none of the above

5418. A zener diode has ______________ breakdown voltage?
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A. zero

B. none of the above

C. sharp

D. undefined

5419. If the PIV rating of a diode is exceeded,_______________?
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A. the diode is destroyed

B. the diode behaves like a zener diode

C. none of the above

D. the diode conducts poorly

5420. A crystal diode has______________?
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A. two pn junctions

B. none of the above

C. three pn junctions

D. one pn junction
5421. If the doping level of a crystal diode is increased, the breakdown voltage__________________?
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A. remains the same

B. none of the above

C. is decreased

D. is increased

5422. Mains a.c. power is converrted into d.c. power for_________________?
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A. using in electronic equipment

B. lighting purposes

C. heaters

D. none of the above

5423. A zener diode is destroyed if it______________?
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A. carrier more than rated current

B. is forward biased

C. is reverse biased

D. none of the above

5424. A crystal diode has forward resistance of the order of ________________?
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A. ?

B. none of the above

C. k?

D. M?

5425. The ripple factor of a half-wave rectifier is_________________?
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A. 2.5

B. 2

C. 0.48

D. 1.21

5426. A crystal diode is used as______________?
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A. a voltage regulator

B. an oscillator

C. a rectifier

D. an amplifier

5427. If the temperature of a crystal diode increases, then leakage current ______________?
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A. becomes zero

B. increases

C. decreases

D. remains the same

5428. A half-wave rectifier has an input voltage of 240 V r.m.s. If the step-down transformer has a turns ratio of 8:1, what is the peak load voltage? Ignore diode drop?
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A. 42.5 V

B. 30 V

C. 86.5 V

D. 27.5 V

5429. The most widely used rectifier is ________________?
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A. bridge full-wave rectifier

B. none of the above

C. centre-tap full-wave rectifier

D. half-wave rectifier

5430. When a crystal diode is used as a rectifier, the most important consideration is ____________?
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A. reverse characteristic

B. PIC rating

C. doping level

D. forward characteristic

5431. The leakage current in a crystal diode is due to _________________?
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A. minority carriers

B. none of the above

C. junction capacitance

D. majority carriers

5432. A zener diode utilizes ______________ characteristics for its operation?
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A. forward

B. reverse

C. both forward and reverse

D. none of the above

5433. The PIV rating of each diode in a bridge rectifier is ___________that of the equivalent center-tap rectifier?
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A. twice

B. the same as

C. one-half

D. four times

5434. For the same secondary voltage, the output voltage from a centre-tap rectifier is___________ than that of bridge rectifier?
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A. four time

B. twice

C. thrice

D. one-half
5435. In the breakdown region, a zener didoe behaves like a _______________source?
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A. none of the above

B. constant current

C. constant voltage

D. constant resistance

5436. A crystal diode is a ________________device?
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A. none of the above

B. non-linear

C. bilateral

D. linear

5437. The knee voltage of a crystal diode is approximately equal to ________________?
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A. breakdown voltage

B. barrier potential

C. applied voltage

D. forward voltage

5438. If the arrow of crystal diode symbol is positive w.r.t. bar, then diode is _____________biased?
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A. none of the above

B. reverse

C. forward

D. either forward or reverse

5439. A crystal diode utilises .. characteristic for rectification
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A. reverse

B. forward or reverse

C. none of the above

D. forward
5440. A zener diode is used as ______________?
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A. a rectifier

B. a multivibrator

C. a voltage regulator

D. an amplifier

5441. A series resistance is connected in the zener circuit to_______________?
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A. none of the above

B. protect the zener

C. properly reverse bias the zener

D. properly forward bias the zener

5442. A 10 V power supply would use ____________ as filter capacitor?
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A. air capacitor

B. electrolytic capacitor

C. paper capacitor

D. mica capacitor

5443. A zener diode has ________________?
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A. three pn junctions

B. two pn junctions

C. one pn junction

D. none of the above

5444. If the a.c. input to a half-wave rectifier is an r.m.s value of 400/?2 volts, then diode PIV rating is__________________?
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A. 400 x ?2 V

B. 400/?2 V

C. 400 V

D. none of the above

5445. When the crystal current diode current is large, the bias is ______________?
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A. forward

B. reverse

C. inverse

D. poor

5446. ____________ rectifier has the lowest forward resistance?
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A. vacuum tube

B. none of the above

C. solid state

D. gas tube

5447. If the doping level in a crystal diode is increased, the width of depletion layer_____________?
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A. in increased

B. is decreased

C. none of the above

D. remains the same

5448. When the graph between current through and voltage across a device is a straight line, the device is referred to as _______________?
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A. passive

B. nonlinear

C. active

D. linear
5449. The maximum efficiency of a half-wave rectifier is _____________?
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A. 81.20%

B. 50%

C. 40.6 %

D. 25%

5450. The d.c. resistance of a crystal diode is ______________ its a.c. resistance?
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A. none of the above

B. the same as

C. more than

D. less than