A silicon sample A is doped with 1018 atoms/cm3 of Boron. Another sample B of identical dimensions is doped with 1018 atoms/cm3 of Phosphorus. The ratio of electron to hole mobility is 3. The ratio of conductivity of the sample A to B is
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Which is the diode used for measuring light intensity?
A. Junction diode
B. Varactor diode
C. Tunnel diode
D. Photodiode
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The drift of a hole in a semiconductor is brought by-
A. The vacancy being filled by an ion
B. The vacancy being filled by a valence electron from a neighbouring atoms
C. The vacancy being filled by a free electron
D. The movement of an atom in the solid
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The width of the energy band depends on which of the following?
A. Temperature
B. Pressure
C. Relative freedom of electrons in the crystal
D. Mass of atom in the material
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Silicon is not suitable for fabrication of light emitting diodes because it is
A. An indirect bandgap semiconductor
B. A direct bandgap semiconductor
C. A wide bandgap semiconductor
D. A narrow bandgap semiconductor
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Bulk resistance of a diode is
A. sum of resistance values of n-material and p-material
B. sum of half the resistance values of n-material and p-material
C. equivalent resistance of the resistance value of p and n-material in parallel
D. none of the above
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Calculate the reverse resistance of a Si diode when the reverse voltage is 50 V and the current is 100 nA.
A. 500 MΩ
B. 100 MΩ
C. 50 MΩ
D. 600 MΩ
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The Fermi level in a p-type semiconductor lies close to
A. top of the valence band
B. bottom of the valence band
C. top of the conduction band
D. bottom of the conduction band
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Match
List-I with
List-II and select the correct answer using the options given below:
List-I (Type of Conductor)List-II (Position of Fermi Level)
a. n-type semiconductor
1. Middle of band gap
b. p-type semiconductor
2. Above conduction band
c. Intrinsic semiconductor
3. Near but below conduction band
d. Degenerate n-type semiconductor
4. Near but above valence 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
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A good ohmic contact on P-type semiconductor chip is formed by introducing
A. gold as an impurity below the contact
B. a high concentration of donors below the contact
C. a high concentration of acceptors below the contact
D. a thin insulator layer between the metal and semiconductor
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VT in MOSFET increases if tox . . . . . . . .
A. Increase
B. Decrease
C. No effect
D. 1st increases then decreases
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Which one of the following statements is correct?
A. by a d.c. source
B. in the middle of its negative resistance region
C. in the positive resistance region nearest to zero
D. in the reverse direction
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The electrodes of a semi-conductor diode are known as:
A. gate and source
B. anode and cathode
C. collector and base
D. cathode and drain
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For current flowing through semiconductor, which of the following statement is true?
A. Only conduction current
B. Only diffusion current
C. Conduction current + Diffusion current
D. None of these
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The device that convert optical radiation into electrical energy is:
A. LED
B. Photo-detector
C. Solar cell
D. P-I-N diode
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If an input signal ranges from 20 µA - 40 µA with an output signal ranging from 0.5 mA - 1.5 mA, what is the βa.c ?
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A depletion mode - MOSFET is characterized by a
A. lightly doped channel between heavily doped source and drain
B. heavily doped channel between lightly doped source and drain
C. enhanced channel between source and drain
D. lightly doped channel between drain and gate
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Temperature range for Ge transistors
A. -25°C to +175°C
B. -65°C to +75°C
C. -65°C to +175°C
D. -25°C to +75°C
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The built-in potential (diffusion potential) in a p-n junction
A. 1 and 2 only
B. 1 and 3 only
C. 1, 2 and 3
D. 2, 3 and 4
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The relative values of the forward conduction voltage for a p-n junction diode, a Red LED and a Schottky barrier diode are
A. Schottky voltage drop > p-n junction diode drop > Red LED drop
B. Red LED drop > p-n junction diode drop > Schottky voltage drop
C. p-n junction diode drop > Schottky voltage drop > Red LED drop
D. Schottky voltage drop > Red LED drop > p-n junction diode drop
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