electrical engineering MCQs – Page 222

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 Review each marked answer and report any item that may be outdated or unclear.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 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
4421. A star circuit has element of resistance R/2. The equivalent delta elements will be_____________?
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A. 2R

B. R/6

C. 4R

D. fi?
4422. The resistance LM will be____________?
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A. 6.66 Q

B. 20Q

C. 12 Q

D. 18Q

4423. If the load current drawn by unregulated power supply increases, the d.c. output voltage _____________?
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A. Decreases

B. Stays the same

C. Increases

D. None of the above

4424. A Zener diode is used as a _____________voltage regulating device?
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A. Series-shunt

B. None of the above

C. Series

D. Shunt
4425. Commercial power supplies have voltage regulation ______________?
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A. within 1%

B. of 15%

C. of 10%

D. of 25%

4426. If the doping level is increased, the breakdown voltage of the Zener_______________?
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A. None of the above

B. Remains the same

C. Is decreased

D. Is increased

4427. A 5 mA changes in Zener current produces a 50 mA change in Zener voltage. What is the Zener impedance ?
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A. 1 O

B. 1 O

C. 100 O

D. 10 O
4428. Which of these is the best description for a Zener diode ?
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A. It works in the forward region

B. It is a constant-voltage device

C. It is a constant current device

D. It is a diode

4429. As the junction temperature increases, the voltage breakdown point for Zener mechanism _______________?
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A. Remains the same

B. Is increased

C. None of the above

D. Is decreased
4430. What is true about the breakdown voltage in a Zener diode ?
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A. It equals current times the resistance

B. It is approximately constant

C. It decreases when load current increases

D. It destroys the diode

4431. For increasing the voltage rating, zeners are connected in_____________?
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A. Series-parallel

B. Parallel

C. Series

D. None of the above

4432. The rupture of co-valent bonds will occur when the electric field is__________________?
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A. 1000 V/cm

B. 6 V/cm

C. More than 105 V/cm

D. 100 V/cm

4433. When load current is zero, the Zener current will be_____________?
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A. Zero

B. Minimum

C. None of the above

D. Maximum
4434. A power supply can deliver a maximum rated current of 0.5 A at full-load output voltage of 20 V. What is the minimum load resistance that you can connect across the supply?
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A. 10 O

B. 40 O

C. 15 O

D. 20 O

4435. A Zener regulator _____________ in the power supply?
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A. Increases the ripple

B. Decreases the ripple

C. Data insufficient

D. Neither increases nor decreases the ripple

4436. In an unregulated power supply, if input a.c. voltage increases, the output voltage _______________?
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A. Increases

B. Remains the same

C. None of the above

D. Decreases

4437. A power supply which has voltage regulation of ____________ is unregulated power supply?
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A. 10 %

B. 5%

C. 0%

D. 8%

4438. Zener diode can be used as__________________?
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A. c. voltage regulator only

B. c. voltage regulator only

C. both D.C and A.C voltage regulator

D. none of the above

4439. A Zener voltage regulator is used for ____________ load currents?
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A. Small

B. High

C. Very high

D. Moderate

4440. In a regulated power supply, two similar 15 V zeners are connected in series. The input voltage is 45 V d.c. If each Zener has a maximum current rating of 300 mA, what should be the value of the series resistance ?
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A. 25 O

B. 10 O

C. 40 O

D. 50 O