14.

SEMICONDUCTOR ELECTRONICS :
MATERIALS, DEVICES AND SIMPLE CIRCUITS
 Previous Years’ T M
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 T M
1 Mark Questions r j u n
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MCQ, Fill in the Blanks and Assertion and Reasoning

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1. The energy band gap is maximum in
(a) metals

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(b) superconductors

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(c) insulators
(d) semiconductors
2. At absolute zero, silicon (Si) acts as
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(a) non metal

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(b) metal

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e
(c) insulator
(d) none of these

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3. The process of adding impurities to a pure semiconductor is called
(a) mixing
(b) doping
(c) diffusing
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(d) none of these
4. Silicon is doped with which of the following to obtain P type semiconductor
(a) Phosphorous
(b) Gallium
(c) Germanium

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(d) Bismuth

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5. When an impurity is doped into an intrinsic semiconductor, the conductivity of the semiconductor
(a) increases

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b
(b) decreases
(c) remains the same

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a
(d) becomes zero

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6. The mobility of free electrons is greater than that of free holes because

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(a) they are light
(b) they carry negative charge
(c) they mutually collide less
(d) they require low energy to continue their motion
7. The forbidden gap for germanium is
(a) 0.12 eV
(b) 0.72 eV
(c) 7.2 eV

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(d) None of these
8. Semiconductor devices require

r j u
(a) large evacuated space

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b
(b) external heating arrangement
(c) low operating voltages

re d
a
(d) high power

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9. When a forward bias is applied to a p-n junction, it

r
p
(a) raises the potential barrier.
(b) reduces the majority carrier current to zero.
(c) lowers the potential barrier
(d) None of the above.
10. In a full wave rectifier, input AC has a frequency ‘ν’. The output frequency of current is
(a) ν /2

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(b) ν

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(c) 2 ν
(d) None of these

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11. In the energy band diagram of a material shown below, the open circles and filled circles denote

A
holes and electrons respectively. The material is

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b
(a) insulator
(b) metal

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a
(c) n-type semiconductor

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(d) p-type semiconductor
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12. As the temperature increases, the electrical resistance
(a) Increases for both conductors and semiconductors
(b) Decreases for both conductors and semiconductors
(c) Increases for conductors but decreases for semiconductors

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(d) Decreases for conductors but increases for semiconductors
13. If a small amount of antimony is added to germanium crystal

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(a) it becomes a p-type semiconductor

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b
(b) the antimony becomes an acceptor atom

e d
(c) there will be more free electrons than holes in the semiconductor

r
a
(d) its resistance is increased

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14. In an n-type semiconductor, which of the following statement is true

r
p
(a) Holes are minority carries and pentavalent atoms are dopants.
(b) Holes are majority carries and trivalent atoms are dopants.
(c) Electrons are majority carries and trivalent atoms are dopants.
(d) Electrons are minority carriers and pentavalent atoms are dopants
15. Which of the following diode is reverse biased?
(a) I
(b) II
(c) III

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(d) IV
16. The usual semiconductors are

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A
(a) germanium and silicon
(b) germanium and copper

by
d
(c) silicon and glass
(d) glass and carbon

a re
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17. The conductivity of a semiconductor will increase with temperature because

p re
(a) number density of free current carriers increases.
(b) relaxation time increases.
(c) both number density of carriers and relaxation time increase.
(d) number density of current carriers increases, relaxation time decreases but effect of decrease in relaxation
time is much less then increase in number density.
18. In a good conductor, the energy gap between valence and conduction band is
(a) 1eV
(b) 6eV
(c) infinite

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(d) zero
19. Electrical conduction in a semiconductor occurs due to

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(a) electron only

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b
(b) holes only

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(c) electrons and holes both
(d) neither electrons nor holes

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20. In ne and nh are the number of electrons and holes in pure germanium, then

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p
(a) ne > nh
(b) ne < nh
(c) ne = nh
(d) ne = infinite and nh = 0
21. In the given figure, assuming the diodes are ideal
(a) D1 is forward biased and D2 is reverse biased and hence

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current flows from A to B.
(b) D2 is forward biased and D1 is reverse biased and hence

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u
current flows from B to A.

A r j
(c) D1 and D2 are both forward biased and hence current flows from A to B.

y
(d) D1 and D2 are both reverse biased and hence no current flows from A to B and vice versa.

d b
22. When an electric field is applied across a semiconductor

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(a) electrons move from lower energy level to higher energy level in the conduction band.

a
p
(b) electrons move from higher energy level to lower energy level in the conduction band.

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(c) holes in the valence band move from higher energy level to lower energy level.
(d) holes in the valence band move from lower energy level to higher energy level.
23. When trivalent impurity is mixed in a pure semiconductor, the conduction is mainly due to
(a) electrons (b) holes
(c) protons (d) positive ions
24. The example of p-type semiconductor is
(a) pure germanium
(b) pure silicon
(c) germanium doped with arsenic

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(d) germanium doped with boron
25. Holes are charge carriers in
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(a) intrinsic semiconductor only

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(b) p-type semiconductor only

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(c) intrinsic and p-type semiconductor

a
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(d) n-type semiconductor

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26. In a semiconductor the concentration of electrons is 8x1013 cm-3 and that of holes is 5x1012 cm-3.
Is it a p-type or n-type semiconductor?
27. In the given figure, is the diode D forward biased or reverse biased?
28. The ______, a property of C, Si and Ge depends upon the energy gap between their conduction
and valence bands.

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29. The ability of a diode to ______ an alternating voltage, is based on the fact that it allows current

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to pass only when it is forward biased.

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ASSERTION/REASONING QUESTIONS
Directions :In the following questions, A statement of Assertion (A) is followed by a statement of
Reason (R). Mark the correct choice as.

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A: If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

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B: If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
C:If the Assertion is correct but Reason is incorrect.

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A
D: If both the Assertion and Reason are incorrect.

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d
30. Assertion: A Pure semiconductor has negative temperature coefficient of resistance.

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Reason: On raising the temperature, more charge carriers are released, conductance increases and

a
p
resistance decreases.

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31. 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.
32. Assertion: The diffusion current in a p-n junction is from the p-side to the n-side.
Reason: The diffusion current in a p-n junction is greater than the drift current when the junction is
in forward biased.

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33. Assertion : The drift current in a p-n junction is from the n-side to the p-side.

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n
Reason : It is due to free electrons only.

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34. Assertion: When diode is used as a rectifier, its specified reverse breakdown voltage should not

A
be exceeded.

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Reason: When p-n junction diode crosses the reverse break down voltage, it gets destroyed

d
35. Assertion : If the temperature of a semiconductor is increased then its conductivity increases.

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Reason: The energy gap between conduction band and valence band is very small

a
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36. Assertion: When a p-n junction diode is reverse biased, a feeble reverse-current flows known as
reverse saturation current.

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Reason: In reverse bias condition, the minority carries can cross the junction.
37. Assertion: The p-n junction diode primarily allows the flow of current only in one direction
(forward bias)
Reason: The forward bias resistance is low as compared to the reverse bias resistance.
38. Assertion: For a half wave rectifier the output frequency is half of input.

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Reason: Half wave rectifier got its name from such a phenomena.
39. Assertion: Diode is an Ohmic conductor.
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Reason: Diodes obey Ohm’s law
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40. Assertion : A p-type semiconductors is a positive type crystal.

a re
Reason : A p- type semiconductor is an uncharged crystal

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than in germanium.
p
41. Assertion: The energy gap between the valance band and conduction band is greater in silicon

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Reason: Thermal energy produces fewer minority carriers in silicon than in germanium.
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2 Mark Questions r j u n
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42. What happens to the width of depletion layer of a p-n junction when it is
(i)forward biased? (ii)reverse biased?

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43. Explain, with the help of a circuit diagram, the working of a p-n junction diode as a half- wave

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rectifier.

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45.Explain how a depletion region is formed in a junction diode?
j n
44. Distinguish between a metal and an insulator on the basis of energy band diagram.

u
y A
46. Carbon and silicon both have four valence electrons each, then how are they distinguished?

b
47. The graph shown in the figure represents a plot of current

d
e
versus voltage for a given semi-conductor. Identify the region,

a r
if any, over which the semi-conductor has a negative resistance.

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48. Plot a graph showing variation of current versus voltage for the material GaAs.
49. Why does the resistivity of semiconductors go down with temperature?

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50. What is meant by intrinsic semiconductor and extrinsic semiconductor? What are the

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differences between intrinsic and extrinsic semiconductor?

n
51. What is meant by doping and doping agent?

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52. Draw the voltage-current characteristic of a p-n junction diode in forward bias and reverse bias.

A
53. Explain, with the help of a circuit diagram, the working of a p-n junction diode as a full- wave

y
b
rectifier.

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forward resistance of diodes to be zero.
d
54. Determine the current I in the circuit shown below. Assume the diodes to be of silicon and

e p a
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55. What are energy bands? Write any two distinguish features between conductors,
semiconductors and insulators on the basis of energy band diagrams.
56. What is the result of doping germanium metal with a little quantity of indium?
57. Who are the major charge carriers in n-type and p-type semiconductors?

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58. Explain with the help of a diagram how the depletion region and potential barrier are formed in

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a junction diode.

A r
59. In a half wave rectifier, what is the frequency of ripple in the output if the frequency of input AC

y
is 50Hz? What is the output ripple frequency of a full wave recitifer?

b
60. A p-n photodiode is fabricated from a semiconductor with band gap of 2.8eV. Can it detect a

d
e
wavelength of 6000nm?

a r
61. The number of silicon atoms per m3 is 5x1028. This is doped simultaneously with 5x1022 atoms

p
e
per m3 of Arsenic and 5x1020 atoms per m3 of Indium. Calculate the number of electrons and holes.

r
Given that n1 = 1.5x1016 per m3. Is the material n-type or p-type?

p
62. Draw a plot showing the variation of resistivity of a (i) conductor and (ii) semiconductor, with
the increase in temperature.
63. Distinguish between intrinsic and extrinsic semiconductors.

T>0K.
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64. Draw the energy band diagram of (i) n-type, and (ii) p-type semiconductors at temperatures

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65. Draw V-I characteristics of a p-n junction diode. Ezplain, why the current under reverse bias is

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almost independent of the applied voltage to the critical voltage.

y A
66. The V-I characteristic of a silicon diode is as shown in the figure. Calculate the resistance of the

b
diode at (i) I=15mA and (ii) V=-10V

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67. The circuit shown in the figure has two oppositely connected ideal diodes connected in
parallel. Find the current flowing through each diode in the circuit.

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b
68. Assuming that the two diodes D1 and D2 used in the electric circuit shown in the figure are

d
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ideal, find out the value of the current flowing through 1Ω resistor.

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 T M
3 Mark Questions r j u n
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69. Draw the circuit diagram of a full wave rectifier using p-n junction diode. Explain its working and
show the output and input waveforms.
70. Write any two distinguishing features between conductors, semiconductors and insulators on

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the basis of energy band diagrams.

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71. (i) Name two important processes that occur during the formation of a p-n junction.

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(ii) Draw the circuit diagram of a full wave rectifier along with the input and output waveforms.

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Briefly explain how the output voltage/current is unidirectional.

A
y
72. Draw V-I characteristics of a p-n junction diode. Answer the following questions, giving reasons:

b
(i)Why is the current under reverse bias almost independent of the applied potential up to a critical

d
e
voltage?

a r
(ii)Why does the reverse current show a sudden increase at the critical voltage.

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73. (i)In the following diagram, which bulb out of B1 and B2 will glow and why ?

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(ii) In the following diagram,is the junction diode forward biased or reverse biased?

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74. An a.c. signal is fed into two circuits X and Y and the corresponding output in the two cases

p a
have the wavefront shown in figure. Name the circuit X and Y. Also draw their detailed circuit
diagram.

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75. A student wants to use two p-n junction diodes to convert alternating current into direct
current. Draw the labelled circuit diagram she would use and explain how it works.
76. Draw the circuit diagram of a half wave rectifier and explain its working.

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 Case Based T M
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Questions j u n
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77. On the basis of energy bands, materials are also defined as metals, semiconductors and
insulators. These semiconductors are classified as intrinsic semiconductors and extrinsic
semiconductors also. Intrinsic semiconductors are those semiconductors which exist in pure

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form. Intrinsic semiconductors have equal number of free electrons and holes. The

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semiconductors doped with some impurity in order to increase its conductivity are called as

n
extrinsic semiconductors. Two types of dopants are used; they are trivalent impurity and

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pentavalent impurity. The extrinsic semiconductors doped with pentavalent impurity like

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Arsenic, Antimony, Phosphorus etc are called as n – type semiconductors. In n-type

y A
semiconductors electrons are the majority charge carriers and holes are the minority charge

b
carriers. When trivalent impurity is like Indium, Boron, Aluminium etc are added to extrinsic

d
semiconductors then p-type semiconductors will be formed. In p-type semiconductors holes

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are majority charge carriers and electrons are the minority charge carriers.

a
p
(I) What is extrinsic semiconductor?

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(II) What is ratio of number of holes and number of electrons in an intrinsic semiconductor?
(III) Why is doping necessary?
(IV) Majority charge carriers in p-type semiconductor are _____.
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78. From Bohr's atomic model, we know that the

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A
electrons have well defined energy levels in an isolated

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atom. But due to interatomic interactions in a crystal,

b
the electrons of the outer shells are forced to have

d
energies different from those in isolated atoms. Each

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energy level splits into a number of energy levels

a
forming a continuous band. The gap between top of

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valence band and bottom of the conduction band in

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which no allowed energy levels for electrons can exist is

p
called energy gap. Following are the energy band
diagrams for conductor fig (ii), for insulators fig (b) and
for semiconductors fig (c).
(I) In an insulator energy band gap is
(a) Eg= 0eV (b) Eg> 3eV

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(c) Eg< 3eV (d) None of this

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(II) In a semiconductor, separation between conduction and valence band is of the order of
(a) Eg= 0eV (b) Eg> 3eV

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A
(c) Eg< 3eV (d) None of this

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(III) Based on the band theory of conductors, insulators and semiconductors, the forbidden gap is
smallest in
(a)conductor

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(b) insulators
d
(c) semiconductors

e p a
(d) All of these

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(IV) Solids having highest energy level partially filled with electrons are
(a)semiconductor
(c) insulator p (b) conductor
(d) none of these
79. Rectifier is a device which is used for converting alternating current or voltage into direct current
or voltage. Its working is based on the fact that the resistance of p-n junction becomes low when
forward biased and becomes high when reverse biased. A half-wave rectifier uses only a single diode

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while a full wave rectifier uses two diodes as shown in figures (a) and (b).

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(I)If the rms value of sinusoidal input to a full wave rectifier is V0/√2 then the rms value of the
rectifier's output is
(a) V0/√2 (b) V0√2 (c) V02 (d) V0/2
(II)In the-diagram, the input ac is across the terminals A and C. The output
across B and D is

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(a) same as the input (b) half wave rectified
(c) zero (d)full wave rectified

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(III)A bridge rectifier is shown in figure. Alternating input is given across

A
A and C. If output is taken across BD, then it is
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y
(a) zero (b) same as input
(c) half wave rectified

d b
(d) full wave rectified

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(IV)A p-n junction (D) shown in the figure can act as a rectifier. An alternating

a
p
current source V is connected in the circuit. The current (I) in the resistor(R)
can be shown by

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80.

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A p-n junction is a single crystal of Ge or Si doped in such a manner that one half portion

a re
of it acts as p-type semiconductor and other half functions as n-type semiconductor. As

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soon as a p-n junction is formed, the holes from the p-region diffuse into the n-region
and electron from n region diffuse in to p-region. This results in the development of VB

p
across the junction which opposes the further diffusion of electrons and holes through
the junction. The current set up by minority charge carriers under the influence of VB is
drift current .Diffusion current and drift current are in opposite directions and no net
flow of charge across the junction.
(I)In an unbiased p-n junction electrons diffuse from n-region to p-region because
(a)holes in p-region attract them
(b)electrons travel across the junction due to potential difference
(c)electron concentration in n-region is more as compared to that in p-region

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(II)In the depletion layer of unbiased p-n junction
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(d)only electrons move from n to p region and not the vice-versa versa

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(a)it is devoid of charge carriers

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(b) has only electrons
(c) has only holes
b
(d) p-n junction has a weak electric field

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(III)The potential of depletion layer is due to
(a) electrons

e p a (b) hole

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(c) ions (d) forbidden band

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(IV)Name the two important processes involved in the formation of a p-n junction.
81. When the diode is forward biased, it is found that beyond forward voltage V = Vk, called knee
voltage, the conductivity is very high. At this value of battery biasing for p-n junction, the potential
barrier is overcome and the current increases rapidly with an increase in forwarding voltage. When

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the diode is reverse biased, the reverse bias voltage produces a very small current about a few

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microamperes which almost remains constant with bias. This small current is reverse saturation

n
current.

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i)In which of the following figures, the p-n diode is forward biased

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d b
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(a) a,b and d p (b) c only (c) c and a (d) b and d
ii)Based on the V-I characteristics of the diode, we can classify diode as
(a)bi-directional device (b) ohmic device
(c) non-ohmic device (d) passive element

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iii)In the case of forwarding biasing of a p-n junction diode, which one of the following statementis

n
correct?
(a)effective barrier potential decreases

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A
(b)majority charge carriers begins to flow away from junction

y
b
(c)width of depletion layer increases

re d
(d)effective resistance across the junction increases

a
iv) If an ideal junction diode is connected as shown, then the value of the current I is

re p
p
(a) 0.005 A (b) 0.02 A (c) 0.01 A (d) 0.1A
82. If an alternating voltage is applied across a diode in series with a load and a pulsating voltage
will appear across the load only during the half cycles of the ac input during which the diode is
forward biased. Such rectifier circuit is called a half-wave rectifier. The reverse saturation current of

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a diode is negligible and can be considered equal to zero for practical purposes.

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a re
i)If input frequency of signal in half wave rectifier is 50 Hz then the output frequency will be
(a) 25 Hz

re p
(b) 50 Hz (c) 100 Hz (d) Uncertain

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ii)In a half wave rectifier, the r.m.s. value of the a.c. component of the wave is
(a) equal to d.c. value (b) more than d.c. value
(c) less than d.c. value (d) Zero
iii) Rectifier converts-
(a) AC to DC (b) DC to AC
(c) AC to AC of different waveform (d) All of these

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iv) Full wave rectifier can be used over half wave rectifier because Full wave rectifier is-
(a)More energy efficient (b) More energy consuming
(c) More handy to use (d) More cost effective to manufacture
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83. There are different techniques of fabrication of p-n junction. In one such technique, called fused
junction techniques, an aluminium film is kept on the wafer of n-type semiconductor and the
combination is then heated to a high temperature (about 600oC). As a result, aluminium fused into
silicon and produces p-type semiconductor and in this way a p-n junction is formed.
i)When a p-n junction is reverse biased, then

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a)No current flows.

u n
c) Height of potential barrier is decreased.

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b)The depletion region is reduced. d) Height of potential barrier is increased.

y A
ii)The cause of potential barrier in p-n junction is :

b
a)Depletion of positive charges near the junction.

d
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b)Concentration of –ve charges near the junction.

a
p
c)Concentration of +ve charges near the junction.

re
d)Concentration of +ve and –ve charges near the junction.

p
iii)The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in
the circuit ?
a)1.17 A c) 2.0 A
b)2.0 A d) 1.33 A

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iv)When a pn junction is forward biased, then
a)Only diffusion current flows.

r j u
A
b)Both diffusion current and drift current flow but diffusion current is more than drift current.

y
b
c)Only drift current flows.

e d
d)Both diffusion and drift current flow but drift current exceeds the diffusion current

r
e p a
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84. A rectifier is an electrical device that converts alternating current (AC), which periodically
reverses direction, to direct current (DC), which flows in only one direction. The reverse operation is
performed by the inverter. This process is known as rectification. From V-I characteristics of a
junction diode, we see that it allows current to pass only when it is forward biased. So, if an

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alternating voltage is applied across a diode the current flows only in that part of the cycle when the
diode is forward biased. This property of diode is used to rectify alternating voltage and the circuit

r j u n
used for this purpose is said to be a rectifier. If an alternating voltage is applied across a diode in
series with a load, a pulsating voltage will appear across the load only during half cycles of the AC

A
input during which diode is forward biased: such type of rectifier circuit is said to be half wave

y
rectifier. This circuit using two diodes gives output rectified voltage corresponding to both the

d b
positive as well as negative half cycle. Hence it is known as full-wave rectifier. For a full wave
rectifier the secondary of the transformer is provided with a centre tapping and so it is called centre

re
tapped transformer. The voltage rectified by each diode is only half the total secondary voltage.

a
Each diode rectifies only for half the cycle, but the two do so for alternating cycles. Thus, the output

e p
between their common terminals and the centre tap of the transformer becomes a full wave

r
p
rectified output.
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(i) In the given figure, assuming the diodes to be ideal, which of the following statements is true?

d b
(a) D1 is forward biased and D2 is reverse biased and hence current
flows from A to B.

a re
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(b) D1 is reverse biased and D2 is forward biased and hence no current

p
flows from B to A and vice versa.
(c) D1 and D2 are both forward biased and hence current flows from A to B.
(d) D1 and D2 are both reverse biased and hence no current flows from B to A and vice versa.
(ii) To reduce the ripples in a rectifier circuit with capacitor filter
(a) RL should be increased
(b) capacitors with high capacitance should be used
(c) input frequency should be increased

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(d) all of the above

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(iii) In a full wave rectifier circuit operating from 50Hz main frequency, the fundamental frequency
in the ripple would be

y A
b
(a) 25Hz (b) 50Hz (c) 75Hz (d) 100Hz

e d
(iv) In the figure shown, the input is across the terminals A and C and the output is across B and D,

r
a
then the output is

e
(a) same as the input

r p
p
(b) full wave rectified
(c) half wave rectified
(d) zero
(v) In a full wave rectifier, the input AC has rms value of 12V. The transformer used is a step up one
having transformation ratio 1:2. The DC voltage in the rectified output is
(a) 20.9V
(b) 21V

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(c) 21.6V
(d) 22V

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85. The process of conversion of an AC voltage into a DC voltage is called rectification and the device which
performs this conversion is called a rectifier. The characteristics on a p-n junction diode reveal that when a p-n
junction diode is forward biased, it offers a low resistance and when it is reverse biased, it offers high

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resistance. Hence, a p-n junction diode conducts only when it is forward biased. This property of a p-n junction

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diode makes it suitable for its use as a rectifier. Thus, when an AC voltage is applied across a p-n junction, it

n
conducts only during those alternate half cycles for which it is forward biased. A recitifer which rectifies only

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half cycle of an AC voltage is called a half wave rectifier and one that rectifies both half cycles is known as full

A
wave rectifier.

by
(i) the root mean square of an alternating voltage applied to a full wave rectifier is V o/√2. The the root mean

d
square value of the rectified output voltage is
(a) Vo/√2(b) (c) 2V0/√2

a re(d) V0/2√2

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(ii) In a full wave rectifier, the current in each of the diode flows for

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p
(a) complete cycle of the input signal
(b) half cycle of the input signal
(c) less than half cycle of the input signal
(d) only for positive half cycle of the input signal
(iii) In a full wave rectifier:
(a) both diodes are forward biased at the same time

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(b) both diodes are reverse biased at the same time
(c) one is forward biased and the other is reverse biased at the same time

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u
(d) both are forward biased in the first half of the cycle and reverse biased in the second half of the
cycle.

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y
(iv) (a) An alternating voltage of frequency of 50Hz is applied to a half wave rectifier. Then the ripple

b
frequency of tjhe output will be
(a) 100Hz (b) 50Hz

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(c) 25Hz (d) 150Hz

a
OR

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(b) A signal, as shown in the figure, is applied to a p-n junction diode. Identify the output across

r
p
resistance RL :
 T M
r j u n
y A
d b
a re
re p
p
 T M
5 Mark Questions r j u n
y A
d b
a re
re p
p
86. Indicate which of the following p- n diodes are forward biased and which are reverse biased:

T M
r j u n
y A
d b
a re
re p
p
87. (i) Sn, C and Si, Ge are all group 14 elements. Yet Sn is a conductor, C is an insulator while Si
and Ge are semiconductor. Why?
(ii)Germanium and silicon junction diodes are connected in parallel. A resistance R, a 12 V battery,

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a milliammeter (mA) and key (K) are connected as shown in figure. When Key (K) is closed, current
begins to flow in milliammeter. What will be the maximum reading of voltmeter connected across

n
resistance R?

r j u
y A
d b
a re
re p
p
88. i) How are p- type semiconductors produced?
ii)The forbidden band energy of silicon is 1.1eV. What does it mean?

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iii)What is an ideal diode?

and the direction of appreciable current in the circuit.

r j u
y A
d b
a re
re p
p
89. (a)Explain with the help of a diagram, how depletion region and potential barrier are formed in
a junction diode.
(b)If a small voltage is applied to a p-n junction diode how will the barrier potential be affected

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when it is (i) forward biased, and (ii) reverse biased ?

T
90. Draw the circuit diagram of a full-wave rectifier using p-n junction diode. Explain its working and

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show the output and input waveforms.

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by
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e p a
p r