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
6051. A certain D-MOSFET is biased at VGS = 0 V. Its data sheet specifies IDSS = 20mA and VGS(off) = -5 V. The value of the drain current is _____________?
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A. 20 mA

B. 0 mA

C. 40 mA

D. 10 mA

6052. In a certain CS JFET amplifier, RD= 1kO , RS= 560 O , VDD=10V and gm= 4500 S. If the source resistor is completely bypassed, the voltage gain is ________________?
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A. 2.52

B. 45

C. 450

D. 4.5

6053. A certain JFET data sheet gives VGS(off) = -4 V. The pinch-off voltage Vp is _____________?
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A. -4 V

B. data insufficient

C. +4 V

D. dependent on VGS

6054. When drain voltage equals the pinch-off-voltage, then drain current ___________ with the increase in drain voltage?
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A. decreases

B. increases

C. none of the above

D. remains constant
6055. The two important advantages of a JFET are _________________?
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A. inexpensive and high output impedance

B. none of the above

C. low input impedance and high output impedance

D. high input impedance and square-law property
6056. In a p-channel JFET, the charge carriers are _____________?
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A. electrons

B. holes

C. both electrons and holes

D. none of the above

6057. _____________ has the lowest noise-level?
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A. triode

B. tetrode

C. JFET

D. ordinary trnsistor

6058. A MOSFET is sometimes called______________ JFET?
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A. open gate

B. many gate

C. insulated gate

D. shorted gate

6059. The pinch-off voltage of a JFET is about _______________?
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A. 25 V

B. 0.6 V

C. 5 V

D. 15 V

6060. A JFET is a__________ driven device?
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A. current

B. voltage

C. both current and voltage

D. none of the above

6061. A n-channel D-MOSFET with a positive VGS is operating in _______________?
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A. the enhancement-mode

B. cut off

C. saturation

D. the depletion-mode

6062. A MOSFET can be operated with________________?
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A. negative gate voltage only

B. positive gate voltage only

C. none of the above

D. positive as well as negative gate voltage
6063. A JFET is also called____________ transistor?
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A. bipolar

B. unipolar

C. unijunction

D. none of the above

6064. A JFET has three terminals, namely________________?
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A. emitter, base, collector

B. none of the above

C. cathode, anode, grid

D. source, gate, drain
6065. A MOSFET uses the electric field of a _______________to control the channel current?
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A. battery

B. none of the above

C. generator

D. capacitor
6066. n a common-source JFET amplifier, the output voltage is _____________?
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A. taken at the source

B. in phase with the input

C. 180o out of phase with the input

D. 90o out of phase with the input

6067. If load resistance in the above question (Q.49) is removed, the output voltage will_____________?
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A. increase

B. stay the same

C. decrease

D. be zero

6068. If the gate of a JFET is made less negative, the width of the conducting channel__________________?
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A. remains the same

B. is increased

C. none of the above

D. is decreased

6069. In a JFET, when drain voltage is equal to pinch-off voltage, the depletion layers ______________?
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A. none of the above

B. have moderate gap

C. almost touch each other

D. have large gap

6070. The input impedance of a MOSFET is of the order of______________?
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A. kO

B. several MO

C. O

D. a few hundred O

6071. In a FET, there are _____________pn junctions at the sides?
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A. four

B. three

C. two

D. five

6072. In a certain common-source D-MOSFET amplifier, Vds =3.2 V r.m. and Vgs = 280 mV r.m.s. The voltage gain is_______________?
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A. 8.75

B. 11.4

C. 1

D. 3.2

6073. A certain common-source JFET has a voltage gain of 10. If the source bypass capacitor is removed, ______________?
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A. the voltage gain will increase

B. the Q-point will shift

C. the voltage gain will decrease

D. the transconductance will increase

6074. The pinch-off voltage in a JFET is analogous to _____________ voltage in a vacuum tube?
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A. none of the above

B. anode

C. cathode

D. grid cut off
6075. A MOSFET has______________ terminals?
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A. three

B. four

C. two

D. five

6076. If the cross-sectional area of the channel in n-channel JEFT increases, the drain current _____________?
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A. is decreased

B. remains the same

C. is increased

D. none of the above

6077. A CS JFET amplifier has a load resistance of 10 kO , RD= 820O . If gm= 5mS and Vin= 500 mV, the output signal voltage is__________________?
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A. 25 V

B. 1.89 V

C. 2.05 V

D. 0.5 V

6078. Which of the following devices has the highest input impedance ?
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A. ordinary transistor

B. Crystal diode

C. JFET

D. MOSFET
6079. A JFET has ____________ power gain?
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A. very small

B. small

C. very high

D. none of the above

6080. The input control parameter of a JFET is __________________?
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A. drain voltage

B. source voltage

C. gate voltage

D. gate current

6081. The output characteristics of a JFET closely resemble the output characteristics of a ___________ valve?
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A. tetrode

B. triode

C. diode

D. pentode
6082. A MOSFET differs from a JFET mainly because _________________?
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A. the MOSFET has two gates

B. none of the above

C. the JFET has a pn junction

D. of power rating

6083. A certain p-channel E-MOSFET has VGS(th) = -2V. If VGS= 0V, the drain current is ____________?
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A. ID(on)

B. IDSS

C. 0 mA

D. maximum

6084. In class A operation, the input circuit of a JFET is ____________ biased?
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A. reverse

B. forward

C. not

D. none of the above

6085. The transconductance of a JFET ranges from ________________?
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A. above 1000 mA/V

B. 100 to 500 mA/V

C. 0.5 to 30 mA/V

D. 500 to 1000 mA/V

6086. The channel of a JFET is between the ________________?
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A. input and output

B. gate and source

C. gate and drain

D. drain and source
6087. The source terminal of a JEFT corresponds to _____________ of a vacuum tube?
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A. grid

B. plate

C. cathode

D. none of the above

6088. If the reverse bias on the gate of a JFET is increased, then width of the conducting channel ______________?
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A. is decreased

B. none of the above

C. is increased

D. remains the same

6089. The gate voltage in a JFET at which drain current becomes zero is called ______________ voltage?
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A. cut-off

B. active

C. pinch-off

D. saturation

6090. For VGS = 0 V, the drain current becomes constant when VDS exceeds ________________?
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A. cut off

B. V

C. VDD

D. VP
6091. A common base configuration of a pnp transistor is analogous to _____________?of a JFET
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A. common gate configuration

B. common source configuration

C. common drain configuration

D. none of the above

6092. At cut-off, the JFET channel is _____________?
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A. at its widest point

B. completely closed by the depletion region

C. reverse baised

D. extremely narrow

6093. The rate of rise of current through an inductive coil is maximum_____________?
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A. at 63.2% of its maximum steady value

B. at the start of the current flow

C. after one time constant

D. near the final maximum value of current

6094. If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be____________?
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A. large

B. small

C. zero

D. none of the above

6095. A material for good magnetic memory should have____________?
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A. low hysteresis loss

B. high retentivity

C. low retentivity

D. high permeability

6096. The unit of retentivity is____________?
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A. ampere turn/meter

B. weber/sq. m

C. ampere turn

D. weber

6097. Hysteresis loss least depends on____________?
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A. steinmetz coefficient of material

B. ambient temperature

C. frequency

D. volume of material

6098. An air gap is usually inserted in magnetic circuits to____________?
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A. prevent saturation

B. increase the flux

C. none of the above

D. increase m.m.f.

6099. Laminated cores, in electrical machines, are used to reduce____________?
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A. all of the above

B. eddy current loss

C. hysteresis loss

D. copper loss

6100. The unit of magnetic flux is______________?
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A. ampereturn/weber

B. ampere/metre

C. weber

D. henry