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
4001. The relay with inverse time characteristic will operate within____________?
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A. none of the above

B. 5 to 20 sec

C. 5 to 10 sec

D. 1.5 sec

E. 20 to 30 sec

4002. transmission line has reflection coefficient as one?
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A. Open circuit

B. None of the above

C. Long

D. Short-circuit

4003. Overheating of relay contacts or contact born out is due to_______________?
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A. all of the above

B. foreign matter on the contact surface

C. slow making and breaking of load circuit contacts

D. too low contact pressure

4004. The voltage appearing across the contacts after opening of the circuit breaker is called__________voltage
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A. recovery

B. none of the above

C. surge

D. arc

E. operating

4005. Magnetic circuit breaker has ___________ trip action
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A. delayed

B. instantaneous

C. both of the above

D. none of the above

4006. The fuse wire, in D.C. circuits, is inserted in____________?
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A. negative circuit only

B. positive circuit only

C. both (A) and (B)

D. either (A) or (B)

4007. Large internal faults are protected by_______________?
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A. earth fault and positive sequence relays

B. horn gaps and temperature relays

C. mho and ohm relays

D. merz price percentage differential protection
4008. The material used for fuse must have_____________?
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A. low melting point and any specific resistance

B. low melting point and -low specific resistance

C. low melting point and high specific resistance

D. high melting point and low specific resistance

4009. The arc voltage produced in A.C. circuit breaker is always_____________?
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A. none of the above

B. in phase with the arc current

C. lagging the arc current by 90?

D. leading the arc current by 90

4010. A differential relay measures the vector difference between_________________?
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A. two currents

B. two or more similar electrical quantities

C. two voltages

D. none of the above

4011. Wave trap is used to trap waves of__________________?
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A. power frequencies

B. higher frequencies entering generator or transformer units

C. either of the above

D. none of the above

4012. The time of closing the cycle, in modern circuit breakers is_____________?
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A. 0.10 sec

B. none of the above

C. 0.003 sec

D. 0.01 sec

E. 0.001 sec

4013. The torque produced in induction type relay (shaded pole structure) is_____________?
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A. inversely proportional to the current

B. proportional to the current

C. proportional to square of the current

D. inversely proportional to the square of the current
4014. An isolator is installed_____________?
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A. to operate the relay of circuit breaker

B. as a substitute for circuit breaker

C. always independent of the position of circuit breaker

D. generally on both sides of a circuit breaker
4015. How many op-amps are required to implement this equation Vo = V1?
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A. 3

B. 1

C. 4

D. 2

4016. The closed-loop voltage gain of an inverting amplifier equal to______________?
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A. The open-loop voltage gain

B. The feedback resistance divided by the input resistance

C. The input resistance

D. The ratio of the input resistance to feedback resistance

4017. An OPAMP has a slew rate of 5 V/? S .The largest sine wave O/P voltage possible at a frequency of 1 MHZ is_______________?
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A. 5/2 volts

B. 10 volts

C. 5/ volts

D. 5 volts

4018. The two input terminals of an opamp are labeled as______________?
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A. High and low

B. Inverting and non inverting

C. Differential ans non differential

D. Positive and negative

4019. In the above circuit the current ix is___________?
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A. 1/12A

B. 0.5A

C. 0.2A

D. 0.6A

4020. For an op-amp having differential gain Av and common-mode gain Ac the CMRR is given by___________?
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A. Av / Ac

B. Av + Ac

C. Ac / Av

D. 1 + Av / AC.

4021. An opamp has a slew rate of 5V/ S. the largest sine wave o/p voltage possible at a frequency of 1MHz is____________?
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A. 10 V

B. 5/2 V

C. 5V

D. 5 V

4022. Calculate the cutoff frequency of a first-order low-pass filter for R1 = 2.5k? and C1 = 0.05?F___________?
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A. 127.3 Hz

B. 1.273kHz

C. 127.3 kHz

D. 12.73kHz

4023. If ground is applied to the (+) terminal of an inverting op-amp, the () terminal will_____________?
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A. Have high reverse current

B. Not invert the signal

C. Not need an input resistor

D. Be virtual ground
4024. Hysteresis is desirable in Schmitt-trigger, because______________?
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A. Energy is to be stored/discharged in parasitic capacitances

B. It would prevent noise from causing false triggering

C. Devices in the circuit should be allowed time for saturation and desaturation

D. Effects of temperature would be compensated

4025. The approximate input impedance of the opamp circuit which has Ri=10k, Rf=100k, RL=10k?
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A. ?

B. 120k

C. 110k

D. 10k

4026. When a step-input is given to an op-amp integrator, the output will be______________?
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A. A ramp

B. A rectangular wave

C. A triangular wave with dc bias

D. A sinusoidal wave

4027. The output voltage Vo of the above circuit is____________?
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A. -1.2V

B. -6V

C. -0.2V

D. -5V
4028. A differential amplifier is invariably used in the i/p stage of all op-amps. This is done basically to provide the op-amps with a very high______________?
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A. CMMR

B. Open-loop gain

C. Bandwidth

D. Slew rate
4029. Differential amplifiers are used in______________?
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A. Voltage followers

B. Buffers

C. Voltage regulators

D. Instrumentation amplifiers
4030. Which of the following amplifier is used in a digital to analog converter?
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A. Difference amplifier

B. Non inverter

C. Summer

D. Voltage follower

4031. A differential amplifier has a differential gain of 20,000. CMMR=80dB. The common mode gain is given by_______________?
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A. 2-Jan

B. 0

C. 2

D. 1

4032. An ideal OP-AMP is an ideal______________?
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A. voltage controlled current source

B. Current controlled Current source

C. Current controlled voltage source

D. Voltage controlled voltage source
4033. Assume that the op-amp of the fig. is ideal. If Vi is a triangular wave, then V0 will be______________?
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A. Triangular wave

B. Parabolic wave

C. Square wave

D. Sine wave
4034. An amplifier using an opamp with slew rate SR=1v/sec has a gain of 40db.If this amplifier has to faithfully amplify sinusoidal signals from dc to 20KHz without introducing any slew-rate induced distortion, then the input signal level exceed_____________?
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A. 795mV

B. 795mV

C. 395mV

D. 39.5mV

4035. How many op-amps are required to implement this equationop-amps?
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A. 2

B. 1

C. 3

D. 4

4036. For an ideal op-amp, which of the following is true?
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A. The current into the input terminals is zero

B. The output resistance is zero

C. The differential voltage across the input terminals is zero

D. The current from output terminal is zero
4037. A non inverting closed loop op amp circuit generally has a gain factor______________?
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A. Greater than one

B. Less than one

C. Equal to one

D. Of zero

4038. The ideal OP-AMP has the following characteristics
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A. Ri=? ,A=? ,R0=?

B. Ri=? ,A=? ,R0=0

C. Ri=0 ,A=? ,R0=0

D. Ri=0 ,A=? ,R0=?

4039. In the differential voltage gain & the common mode voltage gain of a differential amplifier are 48db & 2db respectively, then its common mode rejection ratio is________________?
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A. 46dB

B. 25dB

C. 23dB

D. 50dB

4040. A 741-Type OP-AMP has a gain-bandwith product of 1MHz. A non-inverting amplifier using this opamp & having a voltage gain of 20db will exhibit -3db bandwidth of______________?
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A. 50KHz

B. 1000/17KHz

C. 1000/7.07KHz

D. 100KHz

4041. An ideal OP-AMP is an ideal__________?
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A. Current controlled Current source

B. Voltage controlled Voltage source

C. Voltage controlled Current source

D. Current controlled Voltage source

4042. Class_____________ power amplifier has the highest collector efficiency ?
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A. A

B. B

C. AB

D. C
4043. The most costly coupling is _______________ coupling?
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A. Impedance

B. Direct

C. RC

D. Transformer
4044. Power amplifiers handle ______________ signals compare to voltage amplifiers?
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A. Small

B. Very small

C. Large

D. None of the above

4045. The output signal voltage and current of a power amplifier are 5V and 200 mA; the values being r.m.s. What is the power output ?
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A. 1 W

B. None of the above

C. 2 W

D. 4 W

4046. A power amplifier has comparatively __________________ ?
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A. Small

B. Very large

C. None of the above

D. Large

4047. What turn ratio (Np/Ns) of transformer is required to match 4 O speaker to a transistor having an output impedance of 8000 O ?
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A. None of the above

B. 2

C. 3

D. 7
4048. When a transistor is cut off _________________?
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A. None of the above

B. Maximum voltage appears across transistor

C. Maximum current flows

D. Maximum voltage appears across load

4049. The size of a power transistor is made considerably large to________________?
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A. Provide easy handling

B. None of the above

C. Dissipate heat

D. Facilitate connections

4050. The driver stage usually employs_________________?
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A. Class A power amplifier

B. Push-pull amplifier

C. None of the above

D. Class C amplifier