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
2501. The transition temperature of mercury is____________?
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A. 9.22K

B. 4.12K

C. 1.14K

D. 18.0K

2502. If a radio receiver amplifies all the signal frequencies equally well, it is said to have high ________________?
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A. Selectivity

B. Fidelity

C. Distortion

D. Sensitivity

2503. The impurity atoms is semiconductors_____________?
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A. increase the kinetic energy of valence electrons

B. reduce the energy gap

C. all of the above

D. inject more charge carriers

2504. Class AB operation is often used in power large signal amplifiers in order to_________?
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A. get maximum efficiency

B. remove even harmonics

C. overcome a crossover distortion

D. reducing collector dissipation

2505. __________ is a hard solder?
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A. Tin-silver-lead

B. None of the above

C. Tin-lead

D. Copper-zinc
2506. Due to which of the following factors the brush wear rate is altered ?
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A. Contact pressure

B. Excessive sparking

C. All of the above

D. Surface conditions of brush and commutator

E. Speed of the machine

2507. Due to which of the following fact, in India, aluminium is replacing copper ?
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A. Aluminium is available in plenty, cheaper and lighter than copper

B. Aluminium is more ductile and malleable than copper

C. Aluminium has less temperature co-efficient than copper

D. Aluminium has lower resistivity than that of copper

2508. When the modulating signal controls the frequency of the carrier, we get______________?
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A. Amplitude modulation

B. Frequency modulation

C. Phase modulation

D. May be any one of the above

2509. The diode detector in an AM radio receiver is usually found _____________?
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A. After the first RF stage

B. After several stages of amplification

C. None of the above

D. Before the first RF stage

2510. ___________ is most commonly used for making magnetic recording tape?
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A. Small particles of iron

B. Silver nitrate

C. Ferric oxide

D. Silicon-iron

2511. A tuned amplifier uses__________load?
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A. Inductive

B. LC tank

C. Capacitive

D. Resistive

2512. highest conductivity_____________?
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A. easy solderable and drawable quality

B. good mechanical strength

C. good corrosion resistance

D. all of the above

E. lowest temperature co-efficient

2513. impose limitation on design____________?
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A. Saturation

B. All above

C. Power factor

D. Temperature rise

E. Efficiency

2514. The metal having the lowest temperature coefficient of resistance is_________________?
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A. kanthal

B. aluminium

C. copper

D. gold
2515. 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 20 KHz without introducing any slew-rate induced distortion, then the input signal level must not exceed________?
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A. 395mV

B. 795 mV

C. 39.5mV

D. 795mV

2516. A 50 kW carrier is to be amplitude modulated to a level of 85%. What is the carrier power after modulation ?
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A. 50 kW

B. 5 kW

C. 25 kW

D. 8 kW

2517. The cascade amplifier is a multistage configuration of__________?
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A. CE-CB

B. CC-CB .

C. CE-CC

D. CB-CC

2518. The Q of a tuned amplifier is generally _________________?
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A. More than 10

B. Less than 10

C. None of the above

D. Less than 5

2519. Which of the following is a semiconductor material ?
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A. Phosphorous

B. Rubber

C. Silicon

D. Aluminium

2520. A carbon resistor contains_____________?
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A. carbon crystals

B. finely divided carbon black

C. pulverized coal

D. solid carbon granules

2521. In a radio receiver, we generally use .. oscillator as a local oscillator
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A. Wien-bridge

B. Crystal

C. Phase-shift

D. Hartley
2522. Due to which of the following reasons aluminium does not corrode in atmosphere ?
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A. Atmospheric oxygen can only diffuse very slowly through the oxide layer which is formed on the surface of aluminium

B. Aluminium is a noble metal

C. No reaction with oxygen occurs ft Any of the above

2523. If Amin = 40 and Amax = 60, what is the percentage of modulation?
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A. 20 %

B. 10%

C. 40%

D. 50%

2524. Super conductivity can be destroyed by_____________?
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A. reducing temperatures

B. adding impurities

C. any of the above

D. application of magnetic field
2525. In an op-amp differentiator:________________?
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A. output occurs when input is finite and constant

B. polarity of input and output is the same

C. the amplitude of output is proportional to rate of change of input

D. the amplitude of output is proportional to input

2526. A tuned amplifier is used in ___________ applications?
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A. None of the above

B. Radio frequency

C. Audio frequency

D. Low frequency

2527. MOSFET can be used as a__________?
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A. current controlled inductor

B. current controlled capacitor

C. voltage controlled inductors

D. voltage controlled capacitor
2528. An SCR can exercise control over____________of a.c. supply?
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A. Positive half-cycles only

B. Negative half-cycles only

C. Both positive and negative half-cycles

D. Positive or negative half-cycles
2529. At parallel resonance, the net reactive component circuit current is _______________?
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A. Capacitive

B. None of the above

C. Zero

D. Inductive

2530. Steel wire is used as____________?
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A. all of the above

B. overhead telephone wire

C. earth wire

D. core wire of ACSR

2531. The function of ferrite antenna is to_________________?
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A. Reduce noise

B. Stabilise d.c. bias

C. Reduce stray capacitance

D. Increase the Q of tuned circuit
2532. The conductivity of a metal is determined by____________?
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A. the number of valence electrons per atom

B. either (A) or (B)

C. the electronic concentration and the mobility of the free electrons

D. none of the above

2533. 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 [Hint: Slew rate is defined as the max. rate of change of output voltage. Its unit is V/?S.
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A. 10 volts

B. 5/1 volts

C. 5 volts

D. 5/2 volts
2534. The coils of D.C. motor starter are wound with wire of_______________?
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A. manganin

B. kanthal

C. copper

D. nichrome

2535. At transition temperature the value of critical field is____________?
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A. positive real value

B. complex value

C. zero

D. negative real value

2536. The dimensions of L/CR are that of _______________?
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A. Farad

B. Henry

C. None of the above

D. Ohm
2537. If gate current is increased, then anode-cathode voltage at which SCR closes_________________?
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A. Is decreased

B. Remains the same

C. Is increased

D. None of the above

2538. is a negatively charged particle present in an atom______________?
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A. Neutron

B. None of the above

C. Proton

D. Electron
2539. The resistivity of a metal is a function of temperature because_____________?
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A. the electron gas density varies with temperature

B. the amplitude of vibration of the atoms varies with temperature

C. the electron density varies with temperature

2540. The horizontal intercept of dc load line is the same as ideal____________?
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A. quasi saturation point

B. cut off point

C. saturation point

D. operating point

2541. In a crystal, an atom vibrates at a frequency determined by_______________?
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A. the heat content of the crystal

B. the temperature of the crystal

C. the stiffness of the bonds it makes with neighbors
2542. An npn BJT has gm=38mA/v, c =1014 F, c? =1013F and DC current gain ?0=90.For this transistor fT & f? are________?
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A. fT =1.47 x 1010 Hz & f? = 1.33 x 1012 Hz

B. fT =1.47 x 1010 Hz & f? = 1.64 x 108 Hz

C. fT =1.33 x 1012 Hz & f? = 1.47 x 1010 Hz

D. fT =1.64 x 108 Hz & f? = 1.47 x 1010 Hz.

2543. The co-ordination number of a simple cubic structure is______________?
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A. 8

B. 6

C. 2

D. 4

2544. When a transistor is connected in common emitter mode, it with have__________?
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A. low input resistance as well as output resistance

B. medium input resistance and high output resistance

C. high input resistance and low output resistance

D. negligible input resistance and high output resistance

2545. The action of JFET in its equivalent circuit can best be represented as a_____________?
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A. Voltage controlled voltage source

B. Current controlled Current source

C. Current controlled voltage source

D. voltage controlled current source
2546. An SCR is made of silicon and not germanium because silicon _________________?
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A. Has small leakage current

B. Is tetravalent

C. Is mechanically strong

D. Is inexpensive

2547. An H.R.C. fuse is_______________?
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A. a ceramic body having metal and caps

B. a wire of platinum

C. a heavy cross-section of copper or aluminium

D. a ceramic tube having carbon rod inside it

2548. The signal voltage induced in the aerial of a radio receiver is of the order of ________________?
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A. mV

B. None of the above

C. V

D. V

2549. Which of the following materials is used for making coils of standard resistances ?
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A. Manganin

B. Copper

C. Platinum

D. Nichrome

2550. When an SCR is turned on, the voltage across it is about _____________?
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A. 10 V

B. 1 V

C. 1 V

D. Zero