JEE Questions for Physics Semiconductor Devices Quiz 15 - MCQExams.com

In a forward biased PN-junction diode, the potential barrier in the depletion region is of the form

  • Physics-Semiconductor Devices-88032.png
  • 2)
    Physics-Semiconductor Devices-88033.png

  • Physics-Semiconductor Devices-88034.png

  • Physics-Semiconductor Devices-88035.png
Different voltages are applied across a P — N junction and the currents are measured for each value. Which of the following graphs is obtained between voltage and current?

  • Physics-Semiconductor Devices-88036.png
  • 2)
    Physics-Semiconductor Devices-88037.png

  • Physics-Semiconductor Devices-88038.png

  • Physics-Semiconductor Devices-88039.png
A p — n junction (D) shown in the figure can act as a rectifier. An alternating current source (V) is connected in the circuit.
The current (I) in the resistor (R) can be shown by
Physics-Semiconductor Devices-88040.png

  • Physics-Semiconductor Devices-88041.png
  • 2)
    Physics-Semiconductor Devices-88042.png

  • Physics-Semiconductor Devices-88043.png

  • Physics-Semiconductor Devices-88044.png
The curve between charge density and distance near P–N junction will be

  • Physics-Semiconductor Devices-88045.png
  • 2)
    Physics-Semiconductor Devices-88046.png

  • Physics-Semiconductor Devices-88047.png

  • Physics-Semiconductor Devices-88048.png
The resistance of a germanium junction diode whose V — I is shown in figure is (Vk = 0.3V )
Physics-Semiconductor Devices-88050.png
  • 5 kΩ
  • 0.2 kΩ
  • 2.3 kΩ

  • Physics-Semiconductor Devices-88051.png
The graph given below represents the I — V characteristics of a zener diode. Which part of the characteristics curve is most relevant for its operation as a voltage regulator?
Physics-Semiconductor Devices-88053.png
  • ab
  • bc
  • cd
  • de
The output in the circuit of figure is taken across a capacitor. It is as shown in figure
Physics-Semiconductor Devices-88055.png

  • Physics-Semiconductor Devices-88056.png
  • 2)
    Physics-Semiconductor Devices-88057.png

  • Physics-Semiconductor Devices-88058.png

  • Physics-Semiconductor Devices-88059.png
A source voltage of 8 V drives the diode in fig. through a current-limiting resistor of 100 ohm. Then, the magnitude of the slope load line on the V – I characteristics of the diode is
Physics-Semiconductor Devices-88061.png
  • 0.01
  • 100
  • 0.08
  • 12.5
The i – V characteristic of a P – N junction diode is shown below. The approximate dynamic resistance of the P – N junction when a forward bias of 2 volt is applied
Physics-Semiconductor Devices-88063.png
  • 1 Ω
  • 0.25 Ω
  • 0.5 Ω
  • 5 Ω
In a negative logic the following wave form corresponds to the
Physics-Semiconductor Devices-88065.png
  • 0000000000
  • 0101101000
  • 1111111111
  • 1010010111
The variation of anode current in a triode corresponding to a change in grid potential at three different values of the plate potential is shown in the diagram. The mutual conductance of the triode is
Physics-Semiconductor Devices-88067.png
  • 2.5 m mho
  • 5.0 m mho
  • 7.5 m mho
  • 10.0 m mho
The point representing the cut off grid voltage on the mutual characteristic of triode is
Physics-Semiconductor Devices-88069.png
  • S
  • R
  • O
  • P

Physics-Semiconductor Devices-88071.png

  • Physics-Semiconductor Devices-88072.png
  • 2)
    Physics-Semiconductor Devices-88073.png

  • Physics-Semiconductor Devices-88074.png

  • Physics-Semiconductor Devices-88075.png

Physics-Semiconductor Devices-88077.png

  • Physics-Semiconductor Devices-88078.png
  • 2)
    Physics-Semiconductor Devices-88079.png

  • Physics-Semiconductor Devices-88080.png

  • Physics-Semiconductor Devices-88081.png
The mutual characteristic of triode is

  • Physics-Semiconductor Devices-88083.png
  • 2)
    Physics-Semiconductor Devices-88084.png

  • Physics-Semiconductor Devices-88085.png

  • Physics-Semiconductor Devices-88086.png
The value of amplification factor from the following graph will be
Physics-Semiconductor Devices-88088.png
  • 10
  • 50
  • 25
  • 40
The correct curve between voltage gain (Av) and load resistance (RL ) is

  • Physics-Semiconductor Devices-88090.png
  • 2)
    Physics-Semiconductor Devices-88091.png

  • Physics-Semiconductor Devices-88092.png

  • Physics-Semiconductor Devices-88093.png
The curve between the work function of a metal (ϕ0) and its temperature (T) will be

  • Physics-Semiconductor Devices-88095.png
  • 2)
    Physics-Semiconductor Devices-88096.png

  • Physics-Semiconductor Devices-88097.png

  • Physics-Semiconductor Devices-88098.png
The plate characteristic curve of a diode in space charge limited region is as shown in the figure. The slope of curve at point P is 5.
Physics-Semiconductor Devices-88099.png
  • 111.1 Ω
  • 222.2 Ω
  • 333.3 Ω
  • 444.4 Ω
A material has N atom in its crystal structure which is a hexagonal close packed. Then, the number of electronicstates in a band is
  • N
  • 2N
  • 4N
  • 6N
A P–type semiconductor can be obtained by adding
  • Arsenic to pure silicon
  • Gallium to pure silicon
  • Antimony to pure germanium
  • Phosphorous to pure germanium
The ratio of thermionic currents is (I / I0) for a metal when the temperature is slowly increased from T0 to T as shown in figure. (I and I0 are currents at T and respectively). Then which one is correct?
Physics-Semiconductor Devices-88101.png
  • A
  • B
  • C
  • D
The frequency response curve of RC coupled amplifier is shown in figure. The band width of the amplifier will be
Physics-Semiconductor Devices-88103.png

  • Physics-Semiconductor Devices-88104.png
  • 2)
    Physics-Semiconductor Devices-88105.png

  • Physics-Semiconductor Devices-88106.png

  • Physics-Semiconductor Devices-88107.png
The figure represents variation of triode parameter (µ or rp or gm) with the plate current. The correct variation of µ and rp are given, respectively by the curves
Physics-Semiconductor Devices-88109.png
  • A and B
  • B and C
  • A and C
  • None of these
The mutual characteristic curves of a triode are as shown in figure. The cut off voltage for the triode is
Physics-Semiconductor Devices-88111.png
  • 0 V
  • 2 V
  • –4 V
  • 6 V
For the diode, the characteristic curves are given at different temperatures. The relation between the temperatures is
Physics-Semiconductor Devices-88113.png

  • Physics-Semiconductor Devices-88114.png
  • 2)
    Physics-Semiconductor Devices-88115.png

  • Physics-Semiconductor Devices-88116.png
  • None of these
The output current versus time curve of a rectifier is shown in the figure. The average value of the output current in this case is
Physics-Semiconductor Devices-88117.png
  • 0
  • i0 / π
  • 2i0 / π
  • i0
Which of the following figures correctly shows the phase relation between the input signal and the output signal of triode amplifier?

  • Physics-Semiconductor Devices-88118.png
  • 2)
    Physics-Semiconductor Devices-88119.png

  • Physics-Semiconductor Devices-88120.png

  • Physics-Semiconductor Devices-88121.png
In the figure four plate characteristics of a triode at different grid voltages are shown. The difference between successive grid voltage is 1 V. Which curve will have maximum grid voltage and what is its value?
Physics-Semiconductor Devices-88122.png
  • A, Vg = + 4V
  • B, Vg = + 4V
  • A, Vg = 0
  • D, Vg = 0
The time variations signals are given as in A, B and C. Point out the true statement from the following
Physics-Semiconductor Devices-88123.png
  • A, B and C are analogue signals
  • A and B are analogue, but C is digital signal
  • A and C are digital, but B is analogue signal
  • A and C are analogue, but B is digital signal
A full-wave rectifier circuit with an AC input is shown
The output voltage across RL is represented as
Physics-Semiconductor Devices-88124.png

  • Physics-Semiconductor Devices-88125.png
  • 2)
    Physics-Semiconductor Devices-88126.png

  • Physics-Semiconductor Devices-88127.png

  • Physics-Semiconductor Devices-88128.png

  • Physics-Semiconductor Devices-88129.png
When a potential difference is applied across, the current passing through
  • An insulator at OK is zero
  • A semiconductor at OK is zero
  • A metal at OK is finite
  • A P-N diode at 300K is finite, if it is reverse biased
A transistor is used in common emitter mode as an amplifier. Then,
  • The base-emitter junction is forward biased
  • The base-emitter junction is reverse biased
  • The input signal is connected in series with the voltage applied to the base-emitter junction
  • The input signal is connected in series with the voltage applied to bias the base collector junction
Holes are charge carriers in
  • Intrinsic semiconductors
  • Ionic solids
  • P-type semiconductors
  • Metals
In an n-p-n transistor circuit, the collector current is 10 mA. If 90% of the electrons emitted reach the collector
  • The emitter current will be 9 mA
  • The base current will be 1 mA
  • The emitter current will be 11 mA
  • The base current will be —1 mA
The impurity atoms, with which pure silicon should be doped to make a p-type semiconductor, are those of
  • Phosphorus
  • Boron
  • Antimony
  • Aluminium
Which of the following statements concerning the depletion zone of an unbiased PN junction is (are) true
  • The width of the zone is independent of the densities of the dopants (impurities)
  • The width of the zone is dependent on the densities of the dopants
  • The electric field in the zone is produced by the ionized dopant atoms
  • The electric field in the zone is provided by the electrons in the conduction band and the holes in the valence band
Select the correct statements from the following
  • A diode can be used as a rectifier
  • A triode cannot be used as a rectifier
  • The current in a diode is always proportional to the applied voltage
  • The linear portion of the I-V characteristic of a triode is used for amplification without distortion
Statement-I : The resistivity of a semiconductor increases in temperature
Statement-II : In a conducting solid, the rate of collisions between free electrons and ions increases with increase of temperature
  • Statement I is true, statement II is true; statement II is a correct explanation for statement I
  • Statement I is true, statement II is true; statement II is not a correct explanation for statement I
  • Statement I is true, statement II is false
  • Statement I is false, statement II is true
Assertion The logic gate NOT can be built using diode.
Reason The output voltage and the input voltage of the diode have 180° phase difference.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion The number of electrons in a P-type silicon semiconductor is less than the number of electrons in a pure silicon semiconductor at room temperature.
Reason It is due to law of mass action.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion In a common emitter transistor amplifier the input current is much less than the output current.
Reason The common emitter transistor amplifier has very high input impedance
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion A transistor amplifier in common emitter configuration has a low input impedence.
Reason The base to emitter region is forward biased
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion When PN-junction is forward biased then motion of charge carriers at junction is due to diffusion. In reverse biasing the cause of motion of charge is drifting.
ReasonIn the following circuit emitter is reverse biased and collector is forward biased.
Physics-Semiconductor Devices-88134.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion If the temperature of a semiconductor is increased then it\'s resistance decreases.
<ReasonThe energy gap between conduction band and valence band is very small
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion The temperature coefficient of resistance is positive for metals and negative for P-type semiconductor.
Reason The effective charge carriers in metals are negatively charged whereas in P-type semiconductor they are positively charged.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion Electron has higher mobility than hole in a semiconductor.
Reason Mass of electron is less than the mass of hole.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion An N-type semiconductor has a large number of electrons but still it is electrically neutral.
Reason An N-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion Light emitting diode (LED) emits spontaneous radiation.
Reason LED are forward biased p-n junctions.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
Assertion Silicon is preferred over germanium for making semiconductor devices.
Reason The energy gap for germanium is more than the energy gap of silicon.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
  • If Assertion is true but Reason is false
  • If the Assertion and Reason both are false
  • If Assertion is false but Reason is true
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