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
4301. In induction heating ___________ is abnormally high?
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A. phase angle

B. current

C. voltage

D. frequency
4302. A perfect black body is one that_____________?
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A. absorbs all incident radiations

B. transmits all incident radiations

C. reflects all incident radiations

D. absorbs, reflects and transmits all incident radiations

4303. Radiant heating is used for which of the following ?
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A. Annealing of metals

B. Drying of paints and varnishes

C. Heating of liquids in electric kettle

D. Melting of ferrous metals

4304. Which of the following devices is necessarily required for automatic temperature control in a furnace ?
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A. Thermostat

B. Heating elements of variable resis-tance material

C. Thermocouple

D. Auto-transformer

4305. For intermittent work which of the following furnaces is suitable ?
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A. Either of the above

B. None of the above

C. Core less furnace

D. Indirect arc furnace

4306. Induction heating process is based on which of the following principles ?
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A. Nucleate heating principle

B. Electro-magnetic induction principle

C. Thermal ion release principle

D. Resistance heating principle

4307. Induction heating takes place it which of the following ?
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A. Conducting materials which are magnetic

B. Conducting materials which are non-magnetic

C. Conducting materials which may or may not be magnetic

D. Insulating materials

4308. The electrode of a direct arc furnace is made of____________?
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A. graphite

B. copper

C. tungsten

D. silver

4309. Radiations from a black body are proportional to____________?
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A. T2

B. T1

C. T*

D. T3

4310. Heat transfer by condition will not occur when____________?
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A. temperatures of the two bodies are identical

B. bodies are kept in vacuum

C. bodies are exposed to thermal radiations

D. bodies are immersed in water

4311. In arc furnace the function of choke is______________?
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A. to imprpve, power factor

B. none of the above

C. to reduce severity of the surge

D. to stabilize the arc
4312. method has leading power factor____________?
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A. Dielectric heating

B. Arc heating

C. Induction heating

D. Resistance heating

4313. Due to which of the following reasons it is desirable to have short arc length ?
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A. To increase the life of roof refractory

B. To have better stirring action

C. To achieve better heating

D. All of the above

E. To reduce problem of oxidation

4314. Which of the following insulating materials was suitable for low temperature applications ?
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A. Cork

B. Diatomaceous earth

C. Asbestos paper

D. 80 percent magnesia

4315. In RC coupling, the value of coupling capacitor is about_______________?
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A. 10 F

B. 100 pF

C. 0.01 F

D. 0.1 F

4316. In an RC coupled amplifier, the voltage gain over mid-frequency range_____________?
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A. None of the above

B. Is constant

C. Changes abruptly with frequency

D. Changes uniformly with frequency

4317. An amplifier receives 0.1 W of input signal and delivers 15 W of signal power. What is the power gain in db?
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A. 4 db

B. 8 db

C. 6 db

D. 5 db

4318. A current amplification of 2000 is a gain of_________________?
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A. 200 db

B. 3 db

C. 66 db

D. 20 db

4319. The noise factor of an ideal amplifier expressed in db is_____________?
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A. 1

B. 1

C. 10

D. 0
4320. A gain of 1,000,000 times in power is expressed by_____________?
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A. 600 db

B. 120 db

C. 30 db

D. 60 db
4321. The number of stages that can be directly coupled is limited because___________?
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A. None of the above

B. Changes in temperature cause thermal instability

C. Circuit becomes heavy and costly

D. It becomes difficult to bias the circuit

4322. In the initial stages of a multistage amplifier, we use______________?
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A. None of the above

B. RC coupling

C. Direct coupling

D. Transformer coupling

4323. Transformer coupling provides high efficiency because___________?
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A. resistance is low

B. none of the above

C. Collector voltage is stepped up

D. collector voltage is stepped down

4324. The output of a microphone is rated at -52 db. The reference level is 1V under specified conditions. What is the output voltage of this microphone under the same sound conditions?
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A. 2 mV

B. 8 mV

C. 5 mV

D. 5 mV
4325. RC coupling is not used to amplify extremely low frequencies because____________?
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A. Electrical size of coupling capacitor becomes very large

B. There is considerable power loss

C. None of the above

D. There is hum in the output

4326. The bandwidth of a single stage amplifier is_____________that of a multistage amplifier?
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A. Data insufficient

B. The same as

C. Less than

D. More than
4327. The value of emitter capacitor CE in a multistage amplifier is about____________?
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A. 50 F

B. 1 F

C. 100 pF

D. 0.01 F

4328. A gain of 1000 times in voltage is expressed by_______________?
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A. 120 db

B. 600 db

C. 30 db

D. 60 db
4329. RC coupling is used for_____________amplification?
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A. Power

B. Voltage

C. Current

D. None of the above

4330. In practice, voltage gain is expressed______________?
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A. None of the above

B. In db

C. In volts

D. As a number

4331. In transistor amplifiers, we use_____________transformer for impedance matching?
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A. e of the above

B. Same turn ratio

C. Step down

D. Step up

4332. The power output of an audio system is 18 W. For a person to notice an increase in the output (loudness or sound intensity) of the system, what must the output power be increased to ?
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A. 6 W

B. 68 W

C. 2 W

D. None of the above

4333. The upper or lower cut off frequency is also called______________frequency?
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A. 3 db

B. Sideband

C. None of the above

D. Resonant

4334. The ear is not sensitive to___________?
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A. Amplitude distortion

B. Frequency distortion

C. e of the above

D. Frequency as well as amplitude distortion

4335. The purpose of RC or transformer coupling is to_____________?
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A. e of the above

B. Increase thermal stability

C. Block a.c.

D. Separate bias of one stage from another
4336. RC coupling is generally confined to low power applications because of____________?
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A. Large number of components

B. None of the above

C. Low efficiency

D. Large value of coupling capacitor

4337. An advantage of RC coupling scheme is the___________?
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A. High efficiency

B. Economy

C. None of the above

D. Good impedance matching

4338. 1 db corresponds to_____________change in power level?
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A. 35%

B. 22%

C. 50%

D. 26%
4339. In obtaining the frequency response curve of an amplifier, the______________?
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A. Generator output level is held constant

B. Generator frequency is held constant

C. Amplifier frequency is held constant

D. Amplifier level output is kept constant

4340. When a multistage amplifier is to amplify d.c. signal, then one must use_____________coupling?
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A. Transformer

B. RC

C. None of the above

D. Direct
4341. The final stage of a multistage amplifier uses______________?
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A. Impedance coupling

B. RC coupling

C. Direct coupling

D. Transformer coupling
4342. If a three-stage amplifier has individual stage gains of 10 db, 5 db and 12 db, then total gain in db is____________?
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A. 14 db

B. 27 db

C. 600 db

D. 24 db

4343. If the power level of an amplifier reduces to half, the db gain will fall by___________?
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A. 2 db

B. 10 db

C. 3 db

D. 5 db

4344. The lower and upper cut off frequencies are also called_____________frequencies?
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A. Resonant

B. Half-resonant

C. Sideband

D. Half-power
4345. The best frequency response is of_____________coupling?
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A. None of the above

B. RC

C. Transformer

D. Direct
4346. In an RC coupling scheme, the coupling capacitor CC must be large enough______________?
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A. Not to attenuate the low frequencies

B. To dissipate high power

C. None of the above

D. To pass d.c. between the stages

4347. The total gain of a multistage amplifier is less than the product of the gains of individual stages due to____________?
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A. use of many capacitors

B. Power loss in the coupling device

C. The use of many transistors

D. Loading effect of the next stage
4348. The frequency response of transformer coupling is___________?
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A. Excellent

B. Poor

C. Good

D. Very good

4349. A radio receiver has____________of amplification?
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A. Three stages

B. Two stages

C. More than one stages

D. One stage

4350. Transformer coupling is used for__________amplification?
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A. Current

B. Power

C. None of the above

D. Voltage