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
4451. In a Zener voltage regulator, the changes in load current produce changes in _________________?
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A. Zener voltage as well as Zener current

B. Zener voltage

C. None of the above

D. Zener current
4452. A Zener diode utilises_____________characteristic for voltage regulation?
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A. Forward

B. Reverse

C. Both forward and reverse

D. None of the above

4453. In an unregulated power supply, if load current increases, the output voltage _____________?
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A. Increases

B. None of the above

C. Decreases

D. Remains the same

4454. In a 15 V Zener diode , the breakdown mechanism will occur by ______________?
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A. Avalanche mechanism

B. Zener mechanism

C. Both Zener and avalanche mechanism

D. None of the above

4455. If the input a.c. voltage to regulated or ordinary power supply increases by 5% what will be the approximate change in d.c. output voltage?
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A. 5%

B. 20%

C. 10%

D. 15%

4456. The load voltage is approximately constant when a Zener diode is ________________?
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A. Unbiased

B. Operating in the breakdown region

C. Reverse biased

D. Forward biased

4457. A Zener voltage regulator will cease to act as a voltage regulator if Zener current becomes______________?
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A. None of the above

B. More than load current

C. Zero

D. Less than load current

4458. Two similar 15 V Zeners are connected in series. What is the regulated output voltage ?
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A. 30 V

B. 45 V

C. 15 V

D. 5 V

4459. A Zener diode______________?
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A. Is a battery

B. Acts like a battery in the breakdown region

C. Is forward biased

D. Has a barrier potential of 1 V

4460. A Zener diode that has very narrow depletion layer will breakdown by____________ mechanism?
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A. Avalanche

B. Zener

C. Both avalanche and Zener

D. None of the above

4461. Another name for Zener diode is ______________diode?
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A. Voltage

B. Power

C. Breakdown

D. Current

4462. In a loaded Zener regulator, which is the largest Zener current ?
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A. None of the above

B. Series current

C. Load current

D. Zener current

4463. The peak value of a sine wave is 200 V. Its average value is___________?
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A. 127.4 V

B. 200V

C. 141.4 V

D. 282.8 V

4464. In a series resonant circuit, the impedance of the circuit is___________?
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A. maximum

B. minimum

C. none of the above

D. zero

4465. In a highly capacitive circuit the__________?
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A. reactive power is more than the apparent power

B. reactive power is more than the actual power

C. actual power is more than its reactive power

D. apparent power is equal to the actual power

4466. The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of_______degrees?
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A. 30

B. 90

C. 60

D. 45
4467. In a circuit containing R, L and C, power loss can take place in____________?
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A. L only

B. C only

C. all above

D. R only
4468. Two waves of the same frequency have opposite phase when the phase angle between them is_________?
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A. 90

B. 360

C. 0

D. 180
4469. Power factor of an inductive circuit is usually improved by connecting capacitor to it in____________?
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A. series

B. parallel

C. none of the above

D. either A. or (b)

4470. The power consumed in a circuit element will be least when the phase difference between the current and voltage is__________?
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A. 0

B. 60

C. 90

D. 180?

4471. Form factor for a sine wave is________?
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A. 1.414

B. 1.11

C. 0.637

D. 0.707

4472. For the same peak value which of the following wave will have the highest r.m.s. value?
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A. sine wave

B. triangular wave

C. half wave rectified sine wave

D. square wave
4473. For a sine wave with peak value Emax _______ 8.30. the average value is?
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A. 0.434 EWc

B. lAUEmax

C. 0.636 Emax

D. 0.707 Emax

4474. The form factor is the ratio of_______?
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A. peak value to r.m.s. value

B. none of the above

C. r.m.s. value to average value

D. average value to r.m.s. value

4475. The double energy transient occur in the____________?
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A. R-L-C circuit

B. R-C circuit

C. purely inductive circuit

D. R-L circuit

4476. For the same peak value, which of the following wave has the least mean value ?
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A. half wave rectified sine wave

B. sine wave

C. square wave

D. triangular wave

4477. Power factor of an electrical circuit is equal to____________?
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A. all of these

B. cosine of phase angle difference be-tween current and voltage

C. ratio of useful current to total current Iw/I

D. R/Z

E. kW/kVA

4478. Power factor of the following circuit will be zero__________?
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A. resistance

B. inductance

C. capacitance

D. both B. and C.
4479. All the rules and laws of D.C. circuit also apply to A.C. circuit containing_____________?
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A. all above

B. capacitance only

C. resistance only

D. inductance only

4480. Pure inductive circuit____________?
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A. does not take power at all from a line

B. none of the above

C. takes power from the line during some part of the cycle and then returns back to it during other part of the cycle

D. consumes some power on average

4481. In a pure inductive circuit___________?
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A. the current lags behind the voltage by 90

B. the current is in phase with the voltage

C. the current can lead or lag by 90

D. the current leads the voltage by 90

4482. For a sine wave with peak value Imax the r.m.s. value is_______?
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A. 0.9

B. 0.707

C. 0.5 Imax

D. 1.414 Lmax

4483. For a frequency of 200 Hz, the time period will be__________?
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A. 0.005 s

B. 0.5 s

C. 0.0005 s

D. 0.05 s

4484. In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value__________?
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A. will change the resonance frequency

B. will increase the selectivity of the circuit

C. will change the maximum value of current at resonance

D. will change the impedance at resonance frequency

4485. The best place to install a capacitor is___________?
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A. any where

B. across the terminals of the inductive load

C. far away from the inductive load

D. very near to inductive load

4486. The product of apparent power and cosine of the phase angle between circuit voltage and current is
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A. volt-amperes

B. true power

C. reactive power

D. instantaneous power

4487. The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_______ohms?
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A. 10

B. 2.5

C. 5

D. 15

4488. The time constant of the capacitance circuit is defined as the time during which voltage________?
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A. none of the above

B. falls to 36.8% of its final steady value

C. rises to 63.2% of its final steady value

D. rises to 38.6% of its final steady value

4489. The power factor at resonance in R-L- C parallel circuit is________?
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A. zero

B. 0.08 lagging

C. 0.8 leading

D. unity
4490. The square waveform of current has following relation between r.m.s. value and average value?
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A. r.m.s. value of current is less than average value

B. r.m.s. value of current is greater than average value

C. none of the above

D. r.m.s. value is equal to average value
4491. The voltage of domestic supply is 220V. This figure represents__________?
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A. peak value

B. mean value

C. r.m.s. value

D. average value

4492. When an alternating current passes through an ohmic resistance the electrical power converted into heat is__________?
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A. none of the above

B. reactive power

C. true power

D. apparent power

4493. In each of the three coils of a three phase generator, an alternating voltage having an r.m.s. value of 220 V is induced. Which of the following values is indicated by the voltmeters ______?
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A. 220 V

B. 220/V3 V

C. none of the above

D. 220V3V

4494. The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing through a given circuit for a given time produces__________?
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A. the same heat as produced by A.C. when flowing through the same circuit

B. the less heat than produced by A.C. flowing through the same circuit

C. the more heat than produced by A.C. when flowing through the same circuit

D. none of the above

4495. The period of a wave is___________?
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A. none of the above

B. the same as frequency

C. time required to complete one cycle

D. expressed in amperes

4496. A pure capacitor connected across an A.C. voltage consumed 50 W. This is due to________?
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A. the current flowing in capacitor

B. the size of the capacitor being quite big

C. the capacitive reactance in ohms

D. the statement is incorrect
4497. The power consumed in a circuit element will be least when the phase difference between the current and voltage is________?
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A. 90

B. 0

C. 180?

D. 60

4498. The transient currents are associated with the____________?
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A. applied voltage to the circuit

B. resistance of the circuit

C. impedance of the circuit

D. changes in the stored energy in the inductors and capacitors
4499. Poor power factor________?
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A. overloads alternators, transformers and distribution lines

B. results in all above

C. reduces load handling capability of electrical system

D. results in more voltage drop in the line

E. results in more power losses in the electrical system

4500. The r.m.s. value and mean value is the same in the case of___________?
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A. triangular wave

B. square wave

C. half wave rectified sine wave

D. sine wave