JEE Questions for Physics Semiconductor Devices Quiz 8 - MCQExams.com

Ripples are ________.
  • A.C. mixed with D.C
  • D.C. mixed with output
  • D.C. output
  • A.C. output
In an P.N.P transistor circuit, the collector current is 10 mA. If 90% of the electrons emitted reach the collector :

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    Physics-Semiconductor Devices-87690.png

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When a P-type semi-conductor is heated :
  • Number of holes increases while that of electrons decreases
  • Number of electron increases while that of hole decreases
  • Number of electrons and holes remains same
  • Number of electrons and holes increases equally
The depletion layer in PN junction diode is caused by
  • Drift of holes
  • Diffusion of impurity ions
  • Diffusion of charge carriers
  • Drift of electrons
The active junction area in a solar cell is ________ as we want ________ power
  • Small, more
  • Small, small
  • Large, more
  • Large, small
The forbidden energy band gap in semi-conductor, conductor and insulator are E1, E2 and E3 respectively. The relation among then is :

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    Physics-Semiconductor Devices-87695.png

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In a common emitter amplifier, output resistance is 5000Ω and input resistance is 1000Ω. If peak value of signal voltage is 1 mV and β =100 , then the peak value of output voltage is _______
  • 0.1V
  • 0.3V
  • 0.2V
  • 0.5V
The A.C. current gain of a transistor is 100. If the base current changes by 100µA, What is the charge in collector current ?
  • 20 mA
  • 30 mA
  • 10 mA
  • 10 µA
In Ge sample, traces of gallium are added as impurity. The resultant sample would behave like :
  • A conductor
  • A P-type semiconductor
  • An N-type semiconductor
  • An insulator
A light emitting diode has a voltage drop of 2V across it when 10mA current is passed. If this LED is to be operated with 6V battery the value of limiting resistor would be_______ .
  • 400Ω
  • 4000Ω
  • 40kΩ
  • 300Ω
NAND gate is __________ .
  • A basic gate
  • Not a universal gate
  • A universal gate
  • Multipurpose gate
The number of holes and electrons in an intrinsic conductors are x and y respectively at room temperature. Which of the following options are true ?
  • x > y
  • y > x
  • x = y
  • x << y
How will you increase the resistivity of Ge semi-conductor ?
  • On adding donor impurity
  • On adding acceptor impurity
  • On making UV light incident on Ge crystal
  • On decreasing the temperature
From the following semi-conductor devices, __________ operates in forward bias only.
  • Varactar diode
  • Zener diode
  • Light emitting diode
  • Photo-diode
___________ device is the odd-one out.
  • Solar-cell
  • Varactor diode
  • Photodiode
  • Zener diode
The value of depletion capacitance ___________ on decreasing the reverse bias on varactor diode
  • Decreases
  • Increases
  • Becomes zero
  • Does not change
Which of the following statement is correct for transistor LC oscillator circuit ?
  • It works with negative feed back
  • The phase difference between output and input signal is π radian
  • To start oscillation external signal is required
  • The frequency of output signal is independent of the components used in feed back circuit
The frequency of output signal of LC oscillator circuit is 100Hz with capacitance value 0.1µF . If value of capacitance is taken as 0.2µF, the frequency of output signal _________.

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    Physics-Semiconductor Devices-87699.png

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The Common Emmiter amplifier has voltage gain equal to 300 and its input signal is 0.5cos(100 t) volt. The output signal will be equal to
  • 150 cos (100t)
  • 300 cos (100t)
  • 150 cos (100t + π )
  • 300 cos (100t – π )
Common base current gain of a NPN transistor is 0.99. The input resistance is 1000Ω and load resistance is 10,000Ω . The voltage gain in common emitter mode is _________ .
  • 9900
  • 99000
  • 99
  • 990

Physics-Semiconductor Devices-87705.png

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    Physics-Semiconductor Devices-87707.png

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Physics-Semiconductor Devices-87710.png

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    Physics-Semiconductor Devices-87712.png

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In a P–type silicon, which of the following statement is true ?
  • Electrons are majority charge carries and trivalent atoms are the dopants
  • Electrons are minority charge carries and pentavalent atoms are dopants
  • Holes are minority charge carriess and pentavalent atoms are dopants
  • Hole are majority charge carries and trivalent atoms are dopants
A zener diode used as voltage regulator is connected ___________.
(i) in forward bias
(ii) in reverse bias
(iii) in parallel with load
(iv) in series with load
  • (i) and (ii) are correct
  • (ii) and (iii) are correct
  • only (i) is correct
  • only (iv) is correct
A n-p-n transistor is used in common emitter made in an amplifier circuit. A change of40µA in the base current changes the output current by 2mA and 0.04V in input voltage.
The input resistance is ________ .
  • 1kΩ
  • 10Ω
  • 10 kΩ
  • 100Ω
A n-p-n transistor is used in common emitter made in an amplifier circuit. A change of40µA in the base current changes the output current by 2mA and 0.04V in input voltage.
The current amplification factor is _________ .
  • 20
  • 30
  • 50
  • 40
A n-p-n transistor is used in common emitter made in an amplifier circuit. A change of40µA in the base current changes the output current by 2mA and 0.04V in input voltage.
If a load of 6kΩ is used, then the voltage gain of the amplifier is __________ .
  • 100
  • 200
  • 300
  • 400
An amplifier has voltage gain Av = 1000. The voltage gain in dB is _________ .
  • 20 dB
  • 30 dB
  • 3 dB
  • 60 dB
A potential barrier of 0.6V exists across a P-N junction. If the depletion region is 1µm wide, what is the intensity of electric field in the region ?

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    Physics-Semiconductor Devices-87721.png

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when a PN junction diode is forward biased, then the depletion region is _________ and barrier height is _________ .
  • Reduced, increases
  • Widened, reduced
  • Reduced, reduced
  • Increased, increased
A common-emitter amplifier has a voltage gain of 100, an input impedence of 100Ω and an output impedence of 200Ω .The product of voltage gain and current gain is
  • 1000
  • 3000
  • 5000
  • 500
A P-N photodiode is made of a material with a band gap of 2.0ev. The minimum frequency of the radiation that can be absorbed by the material is nearly (Take hc = 1240eVnm)

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    Physics-Semiconductor Devices-87726.png

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Physics-Semiconductor Devices-87730.png
  • 0.003mA
  • 0.66mA
  • 0.015mA
  • 0.03mA
For a transistor amplifier, the voltage gain
  • Remains constant for all frequencies
  • Is high at high and low frequencies and constant in the mid-frequency range
  • Is low at high and low frequencies and constant in the mid-frequency range
  • None of the above

Physics-Semiconductor Devices-87732.png
  • 1, 0, 1, 1
  • 0, 1, 0, 0
  • 0, 1, 0, 1
  • 1, 1, 1, 0
The manifestation of band structure in solids is due to :
  • Heisenberg's uncertainty principle
  • Pauli's exclusion principle
  • Bohr's correspondence principle
  • Boltzmann's low
Copper and silicon material is cooled down from 600K to 400K then, resistivity of copper ________ and silicon _________ .
  • Increases, decreases
  • Decreases, increases
  • Decreases, decreases
  • Increases, increases
Semi-conductor has phospholous as impurity then it will have __________ .

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    Physics-Semiconductor Devices-87735.png

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Zener diode is used as __________
  • Full. wave rectifier
  • Amplifier
  • A.C. voltage regulator
  • D.C. voltage regulator
Break down voltage of a diode is 5V. By which effect this breakdown occurs in diode ?
  • Only avalanche effect
  • Only zener effect
  • Avalanche or zener effect
  • None of the above
When NPN transistor is used as an amplifier then __________
  • Electron moves from base to collector
  • Hole travels from emitter to base
  • Hole goes to emitter from base
  • Electron goes to base from collector
For __________ gate, the output is 1 only when both input are `0\'
  • AND
  • NAND
  • OR
  • NOR
In VLSI circuits more than __________ gates are contained.
  • 1000
  • 100
  • 10
  • 500
The flow of valence electrons to the left means that holes are flowing.
  • Left
  • Right
  • Either way
  • None
How many free electrons does a P-type semiconductor contain ?
  • Many
  • None
  • Only those produced by thermal energy
  • Same number as holes
Suppose an intrinsic semi-conductor at room temperature has 1 billion free electrons at room temperature. If temperature changes to 75o C, how many holes are there ?
  • Fewer than 1 billion
  • 1 billion
  • More than 1 billion
  • Impossible to say
Which of the following doesn't fit in the group ?
  • Conductor
  • Semi conductor
  • Four valence electrons
  • Crystal structure
What kind of device is a diode ?
  • Bilateral
  • Linear
  • Nonlinear
  • Unipolar
We want a peak load voltage of 40V out of a bridge rectifier, What is the approximate rms value of secondary voltage ?
  • 0V
  • 14.4V
  • 28.3V
  • 56.6V
The load-current is approximately constant when a zener diode is __________ .
  • Forward biased
  • Reverse biased
  • Operating in breakdown region
  • Unbiased
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