1. The electron and hole concentrations in an intrinsic semiconductor are ni per cm3 at 300oK. Now if acceptor impurities are introduced with a concentration of NA per cm3 (where NA > ni), then electron concentration per cm3 at 300oK will be
a. ni
b. ni + NA
c. NA – ni
d. ni2 / NA
Solution :
https://www.youtube.com/watch?v=gwb5IZFKDw0
2. In a P+N junction diode under reverse bias, the magnitude of electric field is maximum at
a. The edge of the depletion region on P side
b. The edge of the depletion region on N side
c. The P+N junction
d. The center of the depletion region on the N side
Solution :
https://www.youtube.com/watch?v=986MG7ote5w
3. The correct full wave rectifier circuit is :
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Solution :
https://www.youtube.com/watch?v=qzbqzCNqYSA
4. A P+N junction has a built in potential of 0.8 volts. The depletion layer width at a reverse bias of 1.2 volts is 2 µm. For a reverse bias of 7.2 volts, the depletion layer width will be
a. 4 µm
b. 4.9µm
c. 8 µm
d. 12 µm
Solution :
https://www.youtube.com/watch?v=YhbWy1waleM
5. Group I lists four types of PN junction diodes. Match each device in Group I with one of the option in Group II to indicate the bias condition of that device in its normal mode of operation.
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Solution :
https://www.youtube.com/watch?v=4KUze2mrsoo
6. The DC current gain (β) of a BJT is 50. Assuming that the emitter injection efficiency is 0.995, the base transport factor is:
a. 0.980
b. 0.985
c. 0.990
d. 0.995
Solution :
https://www.youtube.com/watch?v=VlsDefl-uG0
7. Group I lists four different semiconductor devices. Match each device in Group I with its characteristic property in Group II.
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a. ni
b. ni + NA
c. NA – ni
d. ni2 / NA
2. In a P+N junction diode under reverse bias, the magnitude of electric field is maximum at
a. The edge of the depletion region on P side
b. The edge of the depletion region on N side
c. The P+N junction
d. The center of the depletion region on the N side
3. The correct full wave rectifier circuit is :

4. A P+N junction has a built in potential of 0.8 volts. The depletion layer width at a reverse bias of 1.2 volts is 2 µm. For a reverse bias of 7.2 volts, the depletion layer width will be
a. 4 µm
b. 4.9µm
c. 8 µm
d. 12 µm
5. Group I lists four types of PN junction diodes. Match each device in Group I with one of the option in Group II to indicate the bias condition of that device in its normal mode of operation.

6. The DC current gain (β) of a BJT is 50. Assuming that the emitter injection efficiency is 0.995, the base transport factor is:
a. 0.980
b. 0.985
c. 0.990
d. 0.995
7. Group I lists four different semiconductor devices. Match each device in Group I with its characteristic property in Group II.
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8. For the BJT circuit shown, assume that the β of the transistor is very large and VBE is 0.7 volts. The mode of operation of the BJT is
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a. Cut off
b. Saturation
c. Normal active
d. Inverse active
9. In the CMOS inverter circuit shown, if the Transconductance parameters of the NMOS and PMOS transistors are Kn = Kp = µnCox(Wn/Ln) = µpCox(Wp/Lp) = 40 µA/V2 and their threshold voltages are VTn = |VTp| = 1 volt, the current I is
a. 0 Amp
b. 25 µA
c. 45 µA
d. 90 µA
10. For the zener diode shown in the figure, the zener voltage at knee is 7 volts, the knee current is negligible and the zener dynamic resistance is 10 Ω. If the input voltage (Vi) range is 10 to 16 volts, the output voltage (Vo) ranges from
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11. The figure shows the high frequency capacitance – voltage (C – V) characteristics of MOS capacitor having an area of 1x10-4 cm2. Assume that the permittivity of silicon and SiO2 are 1x10-12 and 3.5x10-13 F/cm respectively.
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i. The gate oxide thickness in the MOS capacitor is
a. 50 nm
b. 143 nm
c. 350 nm
d. 1 µm
ii. The maximum depletion layer width in silicon is
a. 0.143 µm
b. 0.857 µm
c. 1 µm
d. 1.143 µm
iii. Consider the following statements about the C – V characteristics plot :
S1: The MOS capacitor has an N type substrate
S2: If the positive charges are introduced in the oxide, the C – V plot will shift to the left.
Then which one of the following is TRUE .
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