electrical engineering MCQs – Page 332

Practise multiple-choice questions from electrical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

electrical engineering Mcqs

1. economics of power generation 2. analog electronics 3. solid state switching circuits 4. parallel circuits 5. switchgear and protection 6. op amp circuits 7. transistor audio power amplifiers 8. electrostatics 9. heating and welding 10. multi stage transistor amplifiers 11. passive filters 12. network theorems 13. regulated d c power supply 14. a c fundamentals circuits and circuit theory 15. electromagnetic induction 16. power electronics 17. magnetism and electromagnetism 18. transformers 19. modulation and demodulation 20. d c generators 21. semiconductor theory 22. single phase induction motors 23. semiconductor diode 24. hybrid parameters 25. digital electronics 26. oscillators 27. earthing or grounding 28. single stage transistor amplifiers 29. d c motors 30. transistor biasing 31. amplifiers with negative feedback 32. basic electrical 33. electronic instruments 34. synchronous motors 35. field effect transistors fet 36. magnetic circuit 37. control systems 38. industrial drives 39. power generation 40. series parallel circuits 41. transistor tuned amplifiers 42. electrical engineering materials 43. rectifiers and converters 44. integrated circuits 45. scr silicon controlled rectifiers 46. cables 47. polyphase induction motors 48. measurement and instrumentation 49. transistors 50. electrical machine design 51. electrolysis and storage of batteries 52. electric traction 53. transmission and distribution

6621. Which of the following are the applications of D.C. system ?
0

A. Arc lamps for search lights

B. Arc welding

C. Electrolytic and electro-chemical processes

D. All of the above

E. Battery charging work

6622. The advantage of mercury arc rectifier is that________________?
0

A. it is comparatively noiseless

B. it is light in weight and occupies small floor space

C. it has high efficiency

D. it has high overload capacity

E. all of the above

6623. In which of the following equipment direct current is needed ?
0

A. Relays

B. All of the above

C. Telephones

D. Time switches

6624. On which of the following factors the number of phases for which a rectifier should be designed depend ?
0

A. In the output circuit there should be no harmonics

B. all of the above

C. The voltage regulation of the rectifier should be low

D. The power factor of the system should be high

E. The rectifier supply transformer should be utilized to the best ad-vantage

6625. Which of the following statement is incorrect ?
0

A. Copper oxide rectifier is not stable during early life

B. Copper oxide rectifier is not a perfect rectifier

C. Copper oxide rectifier finds use in control circuits

D. Copper oxide rectifier has a low efficiency

E. Copper oxide rectifier is a linear device

6626. In a rotary converter armature currents are______________?
0

A. a.c. only

B. d.c. only

C. partly a.c. and partly d.c.

6627. When a rectifier is loaded which of the following voltage drops take place ?
0

A. Arc voltage drop

B. All of the above

C. Voltage drop in resistance of transformer and smoothing chokes

D. Voltage drop in transformer reactance

6628. In a mercury arc rectifier positive ions are attracted towards______________?
0

A. mercury pool

B. shell bottom

C. anode

D. cathode

6629. The voltage drop at anode, in a mercury arc rectifier is due to_____________?
0

A. high ionization potential

B. self restoring property of mercury

C. energy spent in overcoming the electrostatic field

D. high temperature inside the rectifier

6630. Which of the following methods may be used to convert A.C. system to D.C ?
0

A. Motor-generator sets

B. Rotary converters

C. All of the above

D. Rectifiers

E. Motor converters

6631. Which of the following is reversible in action ?
0

A. Rotary converter

B. Any of the above

C. None of the above

D. Motor generator set

E. Motor converter

6632. A synchronous converter can be started______________?
0

A. from AC. side as induction motor

B. from D.C. side as D.C. motor

C. by means of a small auxiliary motor

D. any of the above methods

E. none of the above methods

6633. A rotary converter is a single machine with______________?
0

A. one armature and one field

B. two armatures and one field

C. one armature and two fields

D. none of the above

6634. In phase-shift control method the control is carried out by varying the of grid voltage
0

A. none of the above

B. phase

C. any of the above

D. magnitude

E. polarity

6635. The potential drop in the arc, in a mercury arc rectifier, varies_____________?
0

A. 0.05 V to 0.2 V per cm length of the arc

B. 2 V to 3.5 V per cm length of the arc

C. none of the above

D. 0.5 V to 1.5 V per cm length of the arc

6636. The ignited or auxiliary anode in mercury arc rectifier is made of____________?
0

A. aluminium

B. copper

C. graphite

D. boron carbide

6637. Which of the following mercury arc rectifier will deliver least undulating current?
0

A. Three-phase

B. Two-phase

C. Six-phase

D. Single-phase

6638. The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?
0

A. They are mechanically strong

B. They do not require any voltage for filament heating

C. Both (A) and (B)

D. None of the above

6639. In selenium rectifiers efficiencies ranging from _______ to _______ percent are attainable?
0

A. 25, 35

B. 40, 50

C. 60, 70

D. 75, 85

6640. The voltage drop between the anode and cathode, of a mercury arc rectifier comprises of the following_____________?
0

A. anode drop, cathode drop and arc drop

B. anode drop and cathode drop

C. anode drop and arc drop

D. cathode drop and arc drop

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