Match List-I with List-II and select the correct answer using the options given below:
List-I (Material)List-II (Energy Level)
a. p-type semiconductor at 0K temperature the conduction
1. Donor energy level is close to the conduction band
b. Intrinsic semiconductor at 0K temperature
2. Acceptor energy level is close to the valence band
c. n-type semiconductor at room temperature
3. Fermi-level is very close to valence band
d. p-type semiconductor at room temperature
4. Fermi-level is half way between the valence band the conduction band
A. a-1, b-2, c-3, d-4
B. a-3, b-4, c-1, d-2
C. a-1, b-4, c-3, d-2
D. a-3, b-2, c-1, d-4
Select an option to see the answer and solution.
A lateral pnp device has base width of 10 µ and diffusion coefficient for base region is 20 cm2 /sec. The base transit time is . . . . . . . .
A. 50 ns
B. 2 ns
C. 25 ns
D. 1 ns
Select an option to see the answer and solution.
Which one of the following element has Forbidden energy band approximately equal to 6 eV?
A. Metal
B. Insulator
C. Conductor
D. Semiconductor
Select an option to see the answer and solution.
The barrier capacitance CT
A. Increases with the width of the space charge layer
B. Increase with increasing reverse voltage
C. Is due to the immobile charges at the junction varying with the applied voltage
D. Can be defined as Q/V
Select an option to see the answer and solution.
Match
List-I with
List-II and select the correct answer using the options given below:
List-I (Equation)List-II (Relation between/Description)
a. Continuity equation
1. Relates diffusion constant with mobility
b. Einstein's equation
2. Relates charge density with electric field
c. Poisson's equation
3. Relates flow with rate of change of concentration in space
d. Diffusion equation
4. Rate of change of minority carrier density with time
A. a-4, b-1, c-3, d-2
B. a-4, b-1, c-2, d-3
C. a-1, b-4, c-2, d-3
D. a-1, b-4, c-3, d-2
Select an option to see the answer and solution.
Consider the following statements in a semiconductor crystal
A. 1, 2 and 4
B. 2 and 4
C. 1, 2 and 3
D. 1 and 3
Select an option to see the answer and solution.
In a bipolar transistor at room temperature if the emitter current is doubled the voltage across its base-emitter junction is
A. Doubles
B. Halves
C. Increases by about 20 mV
D. Decreases by about 20 mV
Select an option to see the answer and solution.
In a junction built - Potential depends on
A. Temperature
B. Doping densities
C. Doping densities & temperature
D. None of these
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The n-channel MOS and p-channel MOS is turned off:
A. If gate source voltage is zero
B. If gate to source voltage is positive
C. If gate to source voltage is negative
D. If gate to drain voltage is positive
Select an option to see the answer and solution.
A block of Silicon is doped with a donor atom density ND = 3 × 1014 atoms/cm3 , and with an acceptor density of NA = 0.5 × 1014 atoms/cm3 find the resultant density of electrons.
A. 4.5 × 1014 electrons/cm3
B. 3.5 × 1014 electrons/cm3
C. 2.5 × 1014 electrons/cm3
D. 5.5 × 1014 electrons/cm3
Select an option to see the answer and solution.
Which of following is most difficult to fabricate in IC?
A. Resistor
B. Transistor
C. FET
D. Capacitor
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Which one of the following statements is TRUE for an 'ideal' power diode?
A. Forward voltage drop is zero and reverse saturation current is non-zero
B. Reverse recovery time is non-zero and reverse saturation current is zero
C. Forward voltage drop is zero and reverse recovery time is zero
D. Forward voltage drop is non-zero and reverse recovery time is zero
Select an option to see the answer and solution.
The lower turn off time of MOSFET as compared to BJT is due to
A. Positive temperature coefficient
B. Absence of minority carriers
C. On state resistance
D. Input impedance
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N-type materials are the type of materials formed by adding group . . . . . . . . elements to the semiconductor crystals.
Select an option to see the answer and solution.
Consider avalanche breakdown in a silicon p+ n junction. The n-region is uniformly doped with a donor density ND . Assume that breakdown occurs when the magnitude of the electric field at any point in the device becomes equal to the critical field Ecrit . Assume Ecrit to be independent of ND . If the built-in voltage of the p+ n junction is much smaller than the breakdown voltage, VBR , the relationship between VBR and ND is given by
A. B. C. N D × V BR = constant
D. Select an option to see the answer and solution.
Light color and visibility is determined in LED by
A. microwave
B. wavelength
C. spectrum
D. capacitance
Select an option to see the answer and solution.
If the reverse bias voltage increase, then what happen to diffusion capacitance.
A. decreases
B. increases
C. remains constant
D. increases exponentially
Select an option to see the answer and solution.
Which one of the following statements is correct in respect of the use of Direct Gap (DG) and Indirect Gap (IG) semiconductors in fabrication of Light Emitting diode?
A. Both DG and IG semiconductors are suitable
B. Only DG semiconductor is suitable
C. DG semiconductor is suitable and some IG materials having proper dopants are also used
D. Only IG semiconductors are suitable
Select an option to see the answer and solution.
Match
List-I with
List-II and select the correct answer using the options given below:
List-I (Biasing of the junctions)List-II (Functions)
a. E-B junction forward bias and C-B junction reverse bias
1. Very low gain amplifier
b. Both E-B and C-B junctions forward bias
2. Saturation condition
c. E-B junctions reverse bias and C-B junction forward bias
3. High gain amplifier
d. Both E-B and C-B junctions reverse bias
4. Cut-off condition
A. a-2, b-3, c-1, d-4
B. a-3, b-2, c-1, d-4
C. a-3, b-2, c-4, d-1
D. a-2, b-3, c-4, d-1
Select an option to see the answer and solution.
For material emitting 4 × 1014 Hz the band gap is . . . . . . . . eV.
A. 14.87
B. 1.33
C. 4.9
D. 1.653
Select an option to see the answer and solution.
