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
3251. Energy consumption in propelling the train is required for which of the following?
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A. Work against the resistance to motion

B. Acceleration

C. All of the above

D. Work against gravity while moving up the gradient

3252. need frequent starting and stopping of electric motors ?
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A. Grinding mills

B. Lifts and hoists

C. Air-conditioners

D. Paper mills

3253. Which of the following motors is preferred when smooth and precise speed control over a wide range is desired ?
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A. Wound rotor induction motor

B. Squirrel cage induction motor

C. D.C. motor

D. Synchronous motor

3254. A semiconductor has generally_______________valence electrons?
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A. 4

B. 2

C. 6

D. 3

3255. Class _____________ operation gives the maximum distortion?
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A. C

B. AB

C. A

D. B

3256. In the design of a biasing circuit, the value of collector load RC is determined by__________________?
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A. None of the above

B. VCE consideration

C. VBE consideration

D. IB consideration

3257. In the above question (Q38.) , what is the collector voltage ?
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A. 6 V

B. 7 V

C. 3 V

D. 8 V

3258. The leakage current in a silicon transistor is about_____________ the leakage current in a germanium transistor?
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A. One hundredth

B. One tenth

C. One thousandth

D. One millionth

3259. Rotor of a motor is usually supported on ___________________ bearings?
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A. bush

B. thrust

C. needle

D. ball or roller
3260. The starting torque of a D.C. motor is independent of which of the following?
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A. Armature current

B. Flux and armature current

C. Speed

D. Flux

3261. Electric locomotives in India are manufactured at______________?
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A. Gorakhpur

B. Jamalpur

C. Bangalore

D. Chittranjan
3262. Which of the following is essentially needed while selecting a motor ?
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A. Starter

B. Foundation pedal

C. Pulley

D. Bearings

3263. In squirrel cage induction motors which of the following methods of starting cannot be used ?
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A. Resistance in stator circuit

B. Star-delta starting

C. Auto-transformer starting

D. Resistance in rotor circuit
3264. A trivalent impurity has______________valence electrons?
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A. 5

B. 3

C. 4

D. 6

3265. The number of passenger coaches that can be attached to a diesel engine locomotive on broad gauge is usually restricted to_____________/
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A. 14

B. 5

C. 10

D. 17

3266. Long distance railways use which of the following ?
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A. 25 kV two phase A.C.

B. 25 kV three phase A.C.

C. 25 kV single phase A.C.

D. 200 V D.C.

3267. Assuming 8 bits for data, 1 bit for parity, I start bit and 2 stop bits, the number of characters that 1200 BPS communication line can transmit is__________________?
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A. 12CPS

B. 10 CPS

C. None of the above

D. 120 CPS

3268. In case of _______________ speed control by injecting e.m.f. in the rotor circuit is possible?
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A. slip ring induction motor

B. d.c. shunt motor

C. synchronous motor

D. schrage motor

3269. A reluctance motor_________________?
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A. is compact

B. requires starting gear

C. is provided with slip rings

D. has high cost

3270. Which of the following motors is preferred for boom hoist of a travelling crane ?
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A. Single phase motor

B. Synchronous motor

C. A.C. slip ring motor

D. Ward-Leonard controlled D.C. shunt motor

3271. The inputs of a NAND gate are connected together. The resulting circuit is _______________?
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A. OR gate

B. AND gate

C. NOT gate

D. None of the above

3272. Thermal runaway occurs when_________________?
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A. Emitter is forward biased

B. Transistor is not biased

C. Collector is reverse biased

D. Junction capacitance is high

3273. The resistivity of a pure silicon is about _______________?
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A. 6000 O cm

B. 6 x 10-8 O cm

C. 3 x 105 O m

D. 100 O cm

3274. The inverter is _________________?
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A. one of the above

B. AND gate

C. OR gate

D. NOT gate
3275. In the depletion region of a pn junction, there is a shortage of_________________?
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A. None of the above

B. Acceptor ions

C. Holes and electrons

D. Donor ions

3276. NAND gates are preferred over others because these__________________?
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A. can be used to make any gate

B. consume least electronic power

C. have lower fabrication area

D. provide maximum density in a chip

3277. Overload capacity of diesel engines is usually restricted to_______________?
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A. 40 percent

B. 2 percent

C. 20 percent

D. 10 percent

3278. A pn junction acts as a__________________?
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A. Controlled switch

B. Bidirectional switch

C. None of the above

D. Unidirectional switch
3279. For three-phase induction motors which of the following is the least efficient method of speed control ?
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A. Combination of cascade and pole changing

B. Pole changing

C. Rheostat control

D. Cascade control

3280. If the maximum collector current due to signal alone is 3 mA, then zero signal collector current should be at least equal to___________________?
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A. 3 mA

B. 1 mA

C. mA

D. 6 mA

3281. If the value of collector current IC increases, then the value of VCE ______________?
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A. None of the above

B. Increases

C. Decreases

D. Remains the same

3282. For germanium transistor amplifier, VCE should_______________for faithful amplification?
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A. Not fall below 0.7 V

B. Be 0.2 V

C. Be zero

D. None of the above

3283. Which of the following methods is used to control speed of 25 kV, 50 Hz single phase traction ?
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A. Series parallel operation of motors

B. All of the above

C. Tap changing control of transformer

D. Reduced current method

3284. The base resistor method is generally used in ________________?
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A. Amplifier circuits

B. None of the above

C. Switching circuits

D. Rectifier circuits

3285. Belted slip ring induction motor is almost invariably used for_________________?
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A. water pumps

B. none of the above

C. centrifugal blowers

D. jaw crushers
3286. A forward biased pn junction diode has a resistance of the order of_____________?
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A. O

B. MO

C. kO

D. None of the above

3287. Which of the following motors is usually preferred for kiln drives ?
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A. Three phase shunt wound com-mutator motor

B. Cascade controlled A.C. motor

C. Slip ring induction motor

D. Any of the above
3288. In a base resistor method, if the value of changes by 50, then collector current will change by a factor ___________________?
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A. 100

B. 200

C. 50

D. 25

3289. Light duty cranes are used in which of the following ?
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A. Automobile workshops

B. Power houses

C. Pumping stations

D. All of the above
3290. For given maximum axle load tractive efforts of AC. locomotive will be_____________?
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A. more than that of D.C. locomotive

B. equal to that of D.C. locomotive

C. none of the above

D. less than that of D.C. locomotive

3291. For good stabilsation in voltage divider bias, the current I1 flowing through R1 and R2 should be equal to or greater than_____________?
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A. 3 IB

B. 10 IB

C. 4 IB

D. 2 IB

3292. In case of steam engines the steam pressure is_______________?
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A. 10 to 15 kgf/cm2

B. 5 to 8 kgf/cm2

C. 1 to 4 kgf/cm2

D. 25 to 35 kgf/cm2

3293. Which of the following motors is used for elevators ?
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A. Induction motor

B. Synchronous motor

C. Any of the above

D. Capacitor start single phase motor

3294. The disadvantage of voltage divider bias is that it has _________________?
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A. None of the above

B. Low base current

C. Many resistors

D. High stability factor

3295. The only function of NOT gate is to__________________?
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A. None of the above

B. Stop signal

C. Invert input signal

D. Act as a universal gate

3296. In case of a steam engine an average coal consumption per km is nearly________________?
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A. 28 to 30 kg

B. 100 to 120 kg

C. 60 to 80 kg

D. 150 to 175 kg

3297. The output stage of a multistage amplifier usually employs _________________?
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A. None of the above

B. Preamplifier

C. Class A power amplifier

D. Push-pull amplifier
3298. The impurity level in an extrinsic semiconductor is about_______________of pure semiconductor ?
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A. 10 atoms for 108 atoms

B. 1 atom for 108 atoms

C. 1 atom for 104 atoms

D. 1 atom for 100 atoms

3299. Specific energy consumption becomes________________?
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A. more on steeper gradient

B. less if distance between stops is more

C. more with high train resistance

D. all of the above
3300. For derries and winches which of the following drives can be used ?
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A. Pole changing squirrel cage motors

B. Any of the above

C. D.C. motors with Ward-leonard con-trol

D. A.C. slip ring motors with variable resistance