Friday, November 2, 2012

ELECTRONIC DEVICES: Part-2 Solved Objective Questions

Objective Questions From Electronic Devices:

[1] In forward mode npn BJT, if the voltage Vcc is increased then the collector current will increase
A. Due to ohm's law, higher Vcc causes higher current
B. Due to base width decrease less carrier recombine in the base region
C. As the gradient of the minority carriers in the base region becomes steeper
D. Due to both the B and C



[2] The barrier voltage present in a junction diode is the effect of
A. The P side and N side of the junction forming a battery
B. The emf required to move the holes fast enough to have the mobility equal to that of the electrons
C. The recombination of charge carriers across the junction leaving behind the opposite charged ions
D. The voltage needed to make the semiconductor material behave as a conductor



[3] Compare to BJT the FET has
A. High input impedance
B. High gain bandwidth product
C. Better current controlled behaviour
D. High noise immunity


[4] An intrinsic semiconductor at absolute zero temperature
A. Has a large number of holes
B. Behaves like an insulator
C. Behaves like a metallic conductor
D. Has few holes and same number of electrons



[5] For the operation of a depletion type N-MOSFET, the gate voltage has to be
A. Low positive
B. High positive
C. High negative
D. Zero



[6] An emitter follower has high input impedance because
A. Large emitter resistance is used
B. Large biasing resistance is used
C. There is negative feedback in the base emitter circuit
D. The emitter base junction is highly reverse biased



[7] In a differential amplifier an ideal CMRR is
A. Infinity
B. Zero
C. -1
D. +1



[8] In a PNP circuit, the collector
A. Has a arrow pointing inward
B. Is positive with respect to the emitter
C. Is biased at a small fraction of the base bias
D. Is negative with respect to the emitter



[9] A PNP transistor can be replaced with an NPN device and the circuit will do the same thing, provided that
A. The power supply or battery polarity is reversed
B. The collector and emitter leads are interchanged
C. The arrow is pointing inward
D. A PNP transistor can never be replaced with NPN transistor



[10] A BJT has 
A. Three PN junctions
B. Three semiconductor layers
C. Two N type layers around a P type layer
D. A low avalanche voltage


[11] The band gap of silicon at room temperature is________
A) 1.3 eV
B) 0.7 eV
C) 1.1 eV
D) 1.4 eV


[12] The primary reason for the widespread use of Silicon in semiconductor device technology is 

A) Abundance of silicon on the surface of the earth
B) Larger bandgap of silicon in comparison to germanium
C) Favorable properties of silicon-dioxide (SiO2)
D) Lower melting Point


[13] The cascade amplifier is a multistage configuration of 

A) CC-CB
B) CE-CB
C) CB-CC
D) CE-CC


[14] In a multi-stage RC coupled amplifier the coupling capacitor______________

A) Limits the low frequency response
B) Limits the high frequency response
C) Does not affect the frequency response
D) Block the DC component without affecting the frequency response


7:00 PM

2 comments:

  1. The answer in question 4 must be (B). Theoretically, at absolute zero, no majority carrier exists, hence an insulator.

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