20+ Best Mcq basic electronics

1➤ In forward region of its characteristics, a diode appears as

an high resistora capacitor.an ON switchan OFF switch

2➤ An electrical breakdown of a p-n junction occurs if

reverse voltage decreases below the ratingforward voltage decreases below the ratingforward voltage increases up to the ratingreverse voltage increase beyond the rating

3➤ In a forward biased pn junction diode, the sequence of events that best describes the mechanism of current flow is

extraction, and subsequent diffusion and generation of minority carriers.extraction, and subsequent drift and recombination of minority carrierinjection, and subsequent drift and generation of minority carriersinjection, and subsequent diffusion and recombination

4➤ The reverse current of a silicon diode is:

Highly bias voltage sensitiveHighly temperature sensitive Both bias voltage and temperature sensitiveIndependent of bias voltage and temperature

5➤ In P-N junction the avalanche breakdown voltage with semiconductor resistivity (a) . (b) . (c) . (d)

decreases or increases in abrupt P-N junction.both the parameters are independentdecreasesincreases

6➤ A p-n junction diode's dynamic conductance is directly proportional to

the thermal voltagethe temperatureits currentthe applied voltage

7➤ What is the reverse recovery time of a diode when switched from forward bias VF to reverse bias VR?

Time to remove stored minority carriers plus the time to bring the diode voltage to reverse bias VR.Time taken by the diode voltage to attain zero valueTime taken by the diode current to reverse.Time taken to remove the stored minority carriers

8➤ The i-v characteristics of a tunnel diode exhibit?

All of these voltage-controlled negative resistance. (c) temperature-controlled positive resistancecurrent-controlled negative resistance current-controlled positive resistance.

9➤ Material used for fabrication of tunnel diode is

Ge or GaAsSi and InSbSi and GaAsGe and InSb

10➤ . The efficiency of a LED for generating light is directly proportional to the

level of doping.current injected. temperatureapplied voltage

11➤ Which is the diode used for measuring light intensity?

Junction diodeVaractor diodeTunnel diodePhotodiode

12➤ Which one of the following statements is correct? A photodiode works on the principle of

photothermal effect.photoconductive effectphotovoltaic effectphotoelectric effect.

13➤ The region of operation of a MOSFET to work as a linear resistor and linear amplifiers are

Saturation and triode respectively Triode and saturation respectively Cut off and saturation respectively Triode and cutoff respectively

14➤ When the drain voltage in an N-MOSFET is negative, it is operating in

Active regionOhmic regionInactive regionReactive region

15➤ A junction FET, can be used as a voltage variable resistor

At pinch off condition well Below pinch off voltage Beyond pinch off voltage For any value of VDS

16➤ The small value of drain to source voltage JFET behaves like a

ResistorConstant current source Constant voltage source Negative resistance

17➤ Which one of the following is not true?

The cut in voltage of silicon diode is larger than that of germanium Reverse saturations current of a silicon diode is much smaller than that of germanium diodeThe reverse saturations current in a BJT approximately doubles for every 10°c rise in temperature None of these

18➤ Compared to BJT a JFET

Has current flow due to Only majority carrier Is less noisyHas less input resistance Has a larger gain bandwidth production

19➤ The shape of transfer characteistics of JFET is very nearly a

Hyperbola ParabolaStraight line None of these

20➤ Thermal runaway is not encountered in FETs because

Ids has zero temperature coefficient Ids has positive temperature coefficient Ids has negative temperature coefficient The mobility of the carrier increase with increase in temperature

21➤ JFET has main drawback of

Having small gain bandwidth product Being noisy Having high output impedance Having low input impedance

22➤ The Ebers-Moll model of a BJT is valid

Only in active modeOnly in active and saturation modeIn active saturation and cut off modeOnly in active and cut off mode

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