Engineering Physics for Bioscience......

Physics for engineering 1st year

1. SRI SHAKTHI INSTITUTE OF ENGINEERING AND TECHNOLOGY
DEPARTMENT OF PHYSICS
QUESTION BANK
Regulation: R2021
Semester: I
Subject code & Subject Name: 21PH121 & Engineering Physics for Bioscience
Prepared by: Dr. C. Pitchumani Violet Mary / Assistant Professor & Head, Physics
UNIT I FREE ELECTRON AND BAND THEORY OF SOLIDS
Marks S.No Questions Marks
Level
( BTL)
CO
Type ( book
back/ AU/
others)
0.5 / 1
1
The electrical behavior of the conducting materials is based on the _______
structure of the materials.
0.5 R CO 1 Book back
2
___________ is a process that involves the motion of charge carriers in a
materials under the influence of an applied electric field.
0.5 R CO 1 Book back
3
The materials that offers little opposition to the flow of an electric current
are known as ___________.
0.5 AN CO 1 Book back
4 Not all materials conduct electricity equally well. Say it True or False? 0.5 R CO 1 Book back
5 __________ electrons are responsible for the electrical conduction in metal. 0.5 R CO 1 Book back
6 Classical free electron theory was proposed by ____________. 0.5 U CO 1 Book back
7 Quantum free electron theory was proposed by ____________. 0.5 R CO 1 Book back
8 Zone theory was proposed by ____________. 0.5 R CO 1 Book back
9 According to zone theory, the electrons moves in a _________ potential. 0.5 AN CO 1 Book back
10
According to classical and quantum free electron theory, the electrons
moves in a _________ potential.
0.5 R CO 1 Book back
11
According to classical free electron theory, the free electrons obeys
________ theory of gases.
0.5 U CO 1 Book back

2. 12
According to classical free electron theory, the free electrons obeys
________ statistics.
0.5 R CO 1 Book back
13
The free electrons exhibit random motion and they collide with positive
ions and neighboring free electrons through ________ collision.
0.5 R CO 1 Book back
14
Increase in electron concentration (n) increases the electrical
conductivity of a material. Say it true or false?
0.5 R CO 1 Book back
15 The microscopic form of Ohm’s is given by __________. 0.5 R CO 1 Book back

16 The experimental value of Lorentz number is given by _____________.
0.5

Book back

17
___________ law states the ratio of the thermal conductivity to electrical
conductivity of a metal is directly proportional to the absolute
temperature.
0.5

Book back

18
_________________ states that only two electrons can occupy the same energy
level.
0.5

Book back

19 The uppermost filled energy level is known as ______________.
0.5

Book back

20
The expression that governs the distribution of electrons among the
energy levels as a function of temperature is known as ______________.
0.5

Book back

21
The probability of finding an electron in a particular quantum state having
an energy EF is given by ______________.
0.5

Book back

22 The probability vale of F(E) lies between ____________.
0.5

Book back

23
The number of energy states lying in the range of energies between E and
E+dE in a given volume of a sample is given by __________.
0.5

Book back

24
In a periodic potential, the potential of the electron at the site of positive
ions is zero and is maximum in between the sites of two positive ions. Say
it true or false?
0.5

Book back

25 The presence of periodic potential in a crystal leads to _________ bands.
0.5

Book back

26 __________ band, the electrons will move freely.
0.5

Book back

27
The energy gap between the valence band and conduction band is called
___________.
0.5

Book back

28
The mass of an electron moving in a periodic potential under the action of
electric or magnetic field is called the __________.
0.5

Book back

29
_________ is the absence of an electron in a particular place in a crystal
lattice and represents a positive charge.
0.5
Book back
Match the following

3. 30 Thermal conductivity Wm
-1
K
-1
0.5

Book back

31 Electrical conductivity Ω
-1
m
-1

0.5

Book back

32 Mobility m
2
V
-1
s
-1
0.5

Book back

33 Lorentz number WΩK
-2

0.5

Book back

34 Relaxation time s
0.5

Book back

35 Resistivity Ωm
0.5

Book back

36 Drift velocity ms
-1
0.5

Book back

37 Density of electrons m
-3
0.5

Book back

38 Fermi energy eV
0.5

Book back

39 Boltzmann constant JK
-1
0.5

Book back

40 Planck’s constant Js
0.5

Book back
2
41 Define electrical conductivity 2 E CO 1
Book back
42 Define thermal conductivity 2 AN CO 1
Book back
43 Define mean free path of electrons 2 AN CO 1
Book back
44 State Wiedemann Franz law 2 E CO 1
Book back
45 What are the merits of classical free electron theory 2 R CO 1
Book back
46 State any four demerits of classical free electron theory 2 R CO 1
Book back
47 Distinguish between electrical and thermal conductivity 2 AN CO 1
Book back
48 What are classifications of solids based on band theory? 2 E CO 1
Book back
49 Draw the Fermi distribution curve at 0K and at any temperature T K 2
Book back

4. 50 Define effective mass of an electron 2 U CO 1
Book back
51 Define density of states and state its importance. 2
Book back
52 List any four postulates of classical free electron theory. 2
Book back
53 Define Fermi energy level. 2
Book back
54
The electrical resistivity of Copper at 27
o
C is 1.72×10
-8
Ωm. Compute its
thermal conductivity if the Lorentz number is 2.26×10
-8
WΩK
-2
2
Book back
55
The thermal and electrical conductivity of Copper at 20
o
C are 390Wm
-1
K
-
1
and 5.87×10
7
Ω
-1
m
-1
respectively. Calculate Lorentz number.
2
Book back
56
The thermal conductivity of copper at 300K is 470 Wm
-1
K
-1
. Calculate the
electrical conductivity of copper at 300K if the Lorentz number is
2.45×10
-8
WΩK
-2

2
Book back
57
Find the thermal conductivity of copper at 20
o
C with a free electron
density of 8.48×10
28
m
-3
. The thermal velocity of copper at 20
o
C is
1.1536×10
5
ms
-1
with a mean free path of 2.8138nm
2
Book back
58
Evaluate the value of Fermi distribution function for an energy kT above
the Fermi energy.
2
Book back
59
Use Fermi distribution function to obtain the value of F(E) for E-EF =
0.01eV at 200K
2
Book back
60 Distinguish free electrons and bound electrons. 2 E CO 1
Book back
5-8
61
A uniform silver wire has a resistivity of 1.54×10
-8
Ωm at room
temperature. For an electric along the wire of 1-volt cm
-1
, compute the
average drift velocity of electron assuming that there are 5.8×10
28

conduction electron m
-3
. Also calculate the mobility.
7 AN CO 1
Book back
62
Calculate the electrical and thermal conductivities for a metal with a
relaxation time 10
-14
s at 300K. Also calculate the Lorentz number using
the above result. (Density of electrons n=6×10
28
m
-3
)
7 A CO 1
Book back
63
A conducting rod contains 8.5×10
28
electrons per cubic meter. Calculate
the electrical conductivity and mobility of electron, if the collision time for
scattering is 2×10
-14
s
7 AN CO 1
Book back
64
The mobility of electron in Copper is 3×10
-3
m
2
V
-1
s
-1
. Assuming
e = 1.6×10
-19
C and m = 9.1×10
-3
kg, calculate the mean free time.
7 AN CO 1
Book back
65
Deduce an expression for electrical conductivity of a conducting material
based on classical free electron theory.
7 AN CO 1
Book back

5. 66
Deduce an expression for thermal conductivity of a conducting material
based on classical free electron theory.
7 AN CO 1
Book back
67 State and Prove Wiedemann Franz law. 7 AN CO 1
Book back
68 Elaborate the origin of energy bands in Solids 7
Book back
69 What are the demerits of classical free electron theory. 7 A CO 1
Book back
70 Outline the postulates of classical free electron theory. 7 A CO 1
Book back
10 -
14
71
On the basis of free electron theory, derive the expression for electrical
conductivity and thermal conductivity of metals and hence deduce
Wiedemann Franz law.
14 AN CO 1
Book back
72
Write an expression for the Fermi energy distribution function, F(E) and
discuss its behavior with change in temperature. Plot F(E) versus E for
T=0K and T>0K.
10 AN CO 1
Book back
73
With the help of Fermi – Dirac statistics, derive the expression for density
of states with in an energy interval E and E+dE.
14 E CO 1
Book back
74
Discuss the Classification of Solids based on energy band gap.
10 A CO 1
Book back
UNIT II SEMICONDUCTING MATERIALS
Marks S.No
Questions
Marks
Level
( BTL)
CO
Type ( book
back/ AU/
others)
0.5 / 1 1 The resistivity of semiconductors varies from ________ Ωm 0.5 AN CO 3 Book back
2 The energy band gap for silicon is _______eV. 0.5 R CO 3 Book back
3 The energy band gap for germanium is _______eV. 0.5 R CO 3 Book back
4
Extremely pure semiconductors without any impurities is known as
_______.
0.5 R CO 3 Book back
5
The binding force between neighboring atoms in semiconductors is
known as _______ bonds.
0.5 R CO 3 Book back
6 At 0K, the silicon material behaves as an insulator due to lack of __________. 0.5 R CO 3 Book back
7
The charge carriers that are responsible for electrical conductivity in
semiconductors are ________.
0.5 R CO 3 Book back

6. 8
In an intrinsic semiconductor, the Fermi level is located in the middle of
_______.
0.5 R CO 3 Book back
9
The electrical conductivity of an intrinsic semiconductor is given by
relation ________.
0.5 R CO 3 Book back
10
A semiconductor which contains impurity due to doping is known as
_______.
0.5 R CO 3 Book back
11
The density of electrons in the conduction band in an intrinsic
semiconductor is given by the expression ________.
0.5 R CO 3 Book back
12
The density of holes in the valence band in an intrinsic semiconductor is
given by the expression ________.
0.5 AN CO 3 Book back
13
In ____________ band gap semiconductor, the top of the valence band and the
bottom of the conduction band occur at the same value of momentum.
0.5 AN CO 3 Book back
14
In ____________ band gap semiconductor, the top of the valence band and the
bottom of the conduction band occur at the different value of momentum.
0.5 AN CO 3 Book back
15
The resistance of the semiconductor decreases with increase in
temperature and vice-versa. Say it True or False?
0.5
AN
16 Light Emitting diodes are commonly made of such compound as __________.
0.5

17
Electron hole pair recombination takes place directly in indirect bandgap
semiconductors. Say it True or False?
0.5
AN
18
Electron hole pair recombination takes place indirectly through traps in
direct bandgap semiconductors. Say it True or False?
0.5
AN
19
In N-type semiconductor, the Fermi level lies exactly in the middle of the
gap between acceptor energy level and the bottom of the conduction
band. Say it True or False?
0.5
AN
20
In P-type semiconductor, the Fermi level lies exactly in the middle of the
gap between acceptor energy level and the top edge of the valence band.
Say it True or False?
0.5

21
Single element semiconductors formed by fourth group elements of the
periodic table are known as ______________ semiconductors.
0.5

22
Semiconductors composed of elements from two or more different groups
of the periodic table are known as ______________ semiconductors.
0.5

23
The crystal structure of the compound semiconductors are related to
______ structure.
0.5

24
During recombination, indirect band gap semiconductors give up the
energy released in the form of ___________
0.5

7. 25
During recombination, direct band gap semiconductors give up the
energy released in the form of ___________
0.5
AN CO 3 Book back
26 The carrier concentration in a P-type semiconductor is given by ___________.
0.5

27
The carrier concentration in a N-type semiconductor is given by
___________.
0.5

28
With the increase in impurity concentration, the Fermi level in the N-type
semiconductor shifts _________________.
0.5

29
With the increase in impurity concentration, the Fermi level in the P-type
semiconductor shifts _________________.
0.5

30
The process by which the electrons and holes move in a semiconductor is
called as _________________.
0.5

31
The flow of electric current due to the motion of charge carriers under the
influence of external electric field is called ________________.
0.5

32 ________ effect is used to determine the type of semiconductor.
0.5

33
The motion of charge carriers from the region of higher carrier
concentration to lower concentration leads to a current called
________________.
0.5

Match the Following
34 Elemental Semiconductor Boron
0.5

35 Compound Semiconductor Silicon
0.5

36 Donor impurity GaAs
0.5

37 Acceptor impurity Phosphorous
0.5

38 Intrinsic semiconductor �
�=
�
�+�
�
2

0.5

39 N-type semiconductor �
�=
�
�+�
??????
2

0.5

40 P-type semiconductor �
�=
�
�+�
??????
2

0.5

2 41 What are semiconductors? Give examples. 2 R CO 3 Book back
42 Based on band gap, define a semiconductor. 2 AN CO 3 Book back
43 What is meant by doping? 2 AN CO 3 Book back
44 Mention the types of semiconductors 2 AN CO 3 Book back

8. 45 Distinguish between Elemental and Compound semiconductor 2 AN CO 3 Book back
46 Distinguish between N-type and P-type semiconductor 2 AN CO 3 Book back
47 Distinguish between Direct and Indirect band gap semiconductor 2 AN CO 3 Book back
48 Distinguish between intrinsic and extrinsic semiconductors. 2 A CO 3 Book back
49 Mention some of the properties of semiconductors. 2 U CO 3 Book back
50 Why do we prefer Si for transistor and GaAs for Laser diodes? 2 AN CO 3 Book back

51
Define Fermi level in a semiconductor. Mention its position in intrinsic
and extrinsic semiconductor at 0K.

52 What is meant by Hall effect?
53 Define Hall coefficient.
54 Mention some of the applications of the Hall effect.

55
For intrinsic silicon, the room temperature electrical conductivity is
4×10
–4
Ω
–1
m
–1
, the electron and hole mobilities are, respectively, 0.14 and
0.048 m
2
/Vs. Compute the electron and hole concentrations at room
temperature.


56
The electron and hole mobilities in In-Sb semiconductor are 6 and
0.2m
2/Vs respectively. At room temperature (300 K), the resistivity of In-
Sb is 2×10
–4
Ωm. Assuming that the material is intrinsic, determine
its intrinsic carrier density at 300 K.


57
Determine the concentration of conduction electrons per cm in pure
silicon, if its conductivity is 5×10
–4
Ω
–1
m
–1
, electron mobility is 0.05 m
2
/Vs.


58
An n-type semiconductor has a resistivity of 20×10
–2
Ωm. The mobility of
electrons through a separate experiment was found to be 100×10
–4
m
2
/Vs.
Find the number of electrons per m
3



59
The intrinsic carrier density is 1.5×10
16
m
-3
. If the mobility of the electron
and hole are 0.13 and 0.05m
2
/Vs respectively, calculate the conductivity.


60
The sample of silicon is doped with 10
16
phosphor atoms/m
3.
Find the Hall
Voltage of a sample with thickness 500mm, area of cross-section 2.25×10
–
3
m
2
, current 1A and magnetic field 10×10
4
Wbm
-2


5-8
61
The energy gap of Silicon is 1.1eV. It’s electron and hole mobilities at 27
o
C
are 0.48 and 0.013m
2
/Vs. Evaluate its conductivity.
7 AN CO 3 Book back
62
The electron and hole mobility in Si are 0.135m
2
/Vs and 0.48m
2
/Vs
respectively at room temperature. If the carrier concentration is 1.5×10
16

m
3
. Calculate the resistivity at room temperature.
7 AN CO 3 Book back
63
Hall coefficient of a specimen of doped silicon is found to be 3.66×10
–
4
m
3
/C. The resistivity of the specimen is 8.93×10
–3
Ωm. Find the mobility
and density of the charge carriers.
7 E CO 3 Book back

9. 64
Assuming Fermi – Dirac statistics, derive expression for the density of
electrons in the conduction band of an intrinsic semiconductor.
7 A CO 3 Book back
65
Assuming Fermi – Dirac statistics, derive expression for the density of
holes in the valence band of an intrinsic semiconductor.
7 A CO 3 Book back
66
Using the expression of density of electrons in the conduction band and
density of holes in the valence band, Obtain an expression for intrinsic
carrier concentration in an intrinsic semiconductor.
7 A CO 3 Book back
67
The electron and hole mobilities in a P-type Germanium are 0.4 and
0.15m
2
/Vs respectively. The density of Boron is 4×10
23
atoms/m
3
and the
carrier concentration is 2.3×10
19
atoms/m
3
. Find the electrical
conductivity before and after the addition of Boron atoms.
7 A CO 3 Book back
68 State the properties of a semiconductor. 7 E CO 3 Book back
69 Elaborate the classification of semiconductors based on purity. 7 AN CO 3 Book back
70 Elaborate the classification of semiconductors based on band gap. 7 AN CO 3 Book back
71
Elaborate the formation of Covalent and Ionic bonding and its
characteristics

72
Elaborate the formation of Metallic and Vander Waals Bonding and its
characteristics

73 Elaborate the classification of semiconductors based on composition. 7 AN CO 3 Book back
10 -
14
74
Obtain an expression with necessary theory for the carrier concentration
of electrons in a N-type semiconductor.
14 E CO2 Book back
75
Obtain an expression with necessary theory for the carrier concentration
of holes in a P-type semiconductor.
14 AN CO 3 Book back
76
Obtain an expression with necessary theory for the carrier concentration
in an intrinsic semiconductor.
10 AN CO 3 Book back
77
Show that for a P-type semiconductor the Hall coefficient is given by ??????
??????=
1
??????
ℎ�
. Elaborate the experimental setup to measure the Hall voltage.
10 A CO 3 Book back
78
Show that for a N-type semiconductor the Hall coefficient is given by ??????
??????=
−
1
??????
??????�
. Elaborate the experimental setup to measure the Hall voltage.
10 A CO 3 Book back
79 Elaborate the classification of solids based on band gap. 10 AN CO 3 Book back
80
The effective masses of electron and holes in Si are 1.05m0 and 0.45m0
(where m0 = 9.1×10
-31
Kg) respectively. The electron and hole mobilities
at room temperature are 1.4×10
6
m
2
/Vs and 0.5×10
6
m
2
/Vs respectively.
Calculate the intrinsic concentration and intrinsic conductivity.
10 A CO 3 Book back

10. 81
Measurement of conductivity will not determine whether the conduction
is due to electron or holes. Enunciate the way of finding the difference
between two type of charge carriers by other parameters.
14
82
For an intrinsic semiconductor, energy gap is 0.4 eV. Find the
concentration of intrinsic charge carriers at 200K assuming that ??????
�
∗
=
??????
??????
∗
=??????
0. (where m0 = 9.1×10
-31
Kg)
10 A CO 3 Book back
UNIT III PHYSICS OF SEMICONDUCTOR DEVICES
Marks S.No Questions Marks
Level
( BTL)
CO
Type ( book
back/ AU/
others)
0.5 / 1
1
__________________ are elementary building blocks of almost all electronic
devices.
0.5 AN CO 4 Book back
2
_________________ is two terminal electronic component that conducts
electric current in one direction.
0.5 AN
CO 4
Book back
3
The boundary that divides the two regions of the P-types and N-type
semiconductor is called as _________________.
0.5 R
CO 4
Book back
4
At __________________ region the electrons and holes combine and neutralize
each other.
0.5 R
CO 4
Book back
5
If no voltage is applied across the junction, some electrons from N-side
move towards the P-side and holes from P-side move towards the N-side.
This process is known as _____________.
0.5 AN
CO 4
Book back
6
A piece of semiconductor in which one half is doped with trivalent
impurity and other half is doped with pentavalent impurity is known as
___________________
0.5 AN
CO 4
Book back
7
When the P-side of the diode is connected to the positive terminal of the
battery and its N-side is connected to the negative terminal of the battery,
the junction is said to be ______________ biased.
0.5 R
CO 4
Book back
8
When the N-side of the diode is connected to the positive terminal of the
battery and its P-side is connected to the negative terminal of the battery,
the junction is said to be ______________ biased.
0.5 R
CO 4
Book back
9
When the applied voltage is greater than the barrier voltage, the depletion
region completely disappears and the junction resistance becomes zero.
Say it True or False?
0.5 AN
CO 4
Book back
10
If the reverse bias voltage increases, a very small current will have made
at the junction due to the movement of minority charge carriers across
the junction. Say it True or False?
0.5 AN
CO 4
Book back
11
The voltage at which the potential barrier is overcome and the current
begins to increase rapidly is known as _________________________.

11. 12
For PN junction diode made with germanium, the knee voltage is about
_______________ Volt



13
For PN junction diode made with silicon, the knee voltage is about
_______________ Volt



14
The process in which an AC voltage is converted into a DC voltage is
known as _______________.



15
An electrical device that converts an AC signal into DC signal is known as
______________.



16
If the rectified output for the circuit is only for half of the input AC voltage,
it is called as ____________________.



17
___________________ is a quantum mechanical phenomenon where particles
with less energy than that of the potential barrier can still cross the energy
barrier, by penetrating through it.



18
A PN diode that exhibits negative resistance due to tunneling effect is
known as _______________ diode.



19
________________ refers to the decrease in flow of current across the diode
when the voltage is increased.



20
The doping density of tunnel diode is _______________ time higher than the
normal PN junction diode.



21 The width of the depletion layer in Tunnel diode is about ___________Å
22
_______________ diode is a metal-semiconductor junction diode which has a
low forward voltage drop which allows the current to flow only in one
direction.



23 The knee voltage for Schottky diode is around ___________________
24
_______________ is a heavily doped PN junction diode normally operated in
the reverse breakdown region.



25
The current across the PN junction diode as a result of exposure of light is
known as _________________ current.



26
The current through a photodiode in the absence of light is known as
_______________ current.



27 Materials used to produce photodiodes includes ______________________.
28
________________ diode allows current to flow in both forward and reverse
bias conditions.



29
The phenomenon of conversion of light into electric current is known as
_______________.



30 The GaP light emitting diode emits ________ color light.
31
A diode that consumes light energy to produce an electric current is
known as _____________.

12. 32 Tunnel diode is generally made up of ________________. 0.5 AN CO 4 Book back
33
A laser diode which makes use of the same type of semiconductor
material on both sides of the junction is known as ________________.
0.5 AN
CO 4
Book back
34
A laser diode which makes use of the different type of semiconductor
materials on both sides of the junction is known as ________________.
0.5 AN
CO 4
Book back
35 ____________ diode emits coherent light waves when it is forward biased. 0.5 AN CO 4 Book back
36
A laser diode is generally made from a single crystal of
_________________________.
0.5 R
CO 4
Book back
2 37 Define tunneling effect. 2 R CO 4 Book back
38 Distinguish Homojunction and Heterojunction semiconductor laser.
39 Distinguish Reverse and Forward biasing.
40 Distinguish Full wave and Half wave rectifier.
41
Draw a neat sketch to represent the Voltage-Current characteristics of
Schottky diode



42 Distinguish PN diode and Schottky diode. 2 AN CO 4 Book back
43 Distinguish PN diode and Tunnel diode. 2 AN CO 4 Book back
44 Distinguish PN diode and LED.
2 AN CO 4 Book back
45
Draw a neat sketch to represent the Voltage-Current characteristics of
PN diode
2 A
CO 4
Book back
46
Draw a neat sketch to represent the Voltage-Current characteristics of
Tunnel diode
2 A
CO 4
Book back
47 Draw a neat sketch to represent the energy band diagram of PN diode 2 A CO 4 Book back
48 What is diode biasing? 2 R CO 4 Book back
49 What is depletion layer? 2 R CO 4 Book back
50 Distinguish LED and Laser. 2 AN CO 4 Book back
5-8 51 Elaborate the formation of PN junction diode. 7 C CO 4 Book back
52 Elaborate the energy diagram of PN junction diode. 7 C CO 4 Book back
53 Elaborate the behavior of PN junction diode under forward biasing. 7 C CO 4 Book back
54 Elaborate the behavior of PN junction diode under reverse biasing. 7 C CO 4 Book back
55 Elaborate the effect of biasing on depletion layer of PN junction diode 7 C CO 4 Book back
56 Distinguish forward and reverse biasing. 7 AN CO 4 Book back
57 Distinguish half-wave and full-wave rectifier. 7 AN CO 4 Book back
58 Elaborate the working of PN junction diode as half-wave rectifier. 7 E CO 4 Book back

13. 59 Elaborate the working of PN junction diode as full-wave rectifier. 7
E CO 4
Book back
10 -
14
60
Elaborate the construction and working of Laser diode with a necessary
diagram.
10
E CO 4
Book back
61
Elaborate the construction and working of Light emitting diode with a
necessary diagram.
10 E CO 4
Book back
62
Elaborate the construction and working of Zener diode with a necessary
diagram.
10 E CO 4
Book back
63
Elaborate the construction and working of Schottky diode with a
necessary diagram.
10 E CO 4
Book back
64
Elaborate the construction and working of Tunnel diode with a
necessary diagram.
10 E CO 4
Book back
65
Elaborate the construction and working of Half wave rectifier and Full
wave rectifier with a necessary diagram.
14
E
CO 4
Book back
66
Elaborate the behavior of PN diode under forward and reverse bias with
a necessary diagram.
14
E
CO 4
Book back
UNIT IV DIELECTRIC MATERIALS
Marks S.No Questions Marks
Level
( BTL)
CO
Type ( book
back/ AU/
others)
0.5 / 1
1
The space around the charge in which its influence is experienced is
known as ________________.
0.5 AN CO 5 Book back
2
A system consisting of two dissimilar charges (q) separated by a small
distance(d) constitute an _______________.
0.5 R
CO 5
Book back
3
The product of the magnitude of the charge (q) and distance between the
two charges (d) is called as ______________________.
0.5 AN
CO 5
Book back
4
The ratio of the permittivity of the medium (ε) to the permittivity of the
free space (ε0)is known as _____________________.
0.5 R
CO 5
Book back
5
The product of the applied electric field and the permittivity of the
medium is given by the relation __________________.
0.5 R
CO 5
Book back
6 The dipole moment per unit volume is defined as __________________. 0.5 AN
CO 5
Book back
7
The average dipole moment is directly proportional to the
__________________ field.
0.5 AN
CO 5
Book back

14. 8
________________ is defined as the ratio of the polarization to the electric
field.
0.5 AN
CO 5
Book back
9 The energy band gap of dielectric material is about ________________. 0.5 AN
CO 5
Book back
10
Production of electric dipole due to the displacement of charged
particles under the action of an electric field is known as ________________.
0.5 R
CO 5
Book back
11
Relative displacement of electron cloud with respect to the nucleus by
the application of an electric field is known as ___________________.
0.5 AN
CO 5
Book back
12
_______________ force tends to separate the nucleus and the electron cloud
from their equilibrium position.
0.5 R
CO 5
Book back
13
_________________ force between the nucleus and electron cloud tries to
maintain the original equilibrium position.
0.5 R
CO 5
Book back
14 The electronic polarizability is given by the relation ________________. 0.5 R CO 5 Book back
15
Relative displacement of anions and cations in opposite directions by the
application of electric field is known as ________________.



16 The ionic polarizability if given by the relation __________________.
17
Alignment of permanent dipoles with respect to the applied electric field
I known as ________________________.



18 The orientation polarizability if given by the relation __________________.
19
The process of charge accumulation at the electrodes by the application
of external electric field is known as _______________________.



20 The expression for Langevin-Debye equation is given by _______________.
Match the following
21 Optical Frequency
Electronic, Ionic, Orientation, Space -
Charge



22 Infrared Frequency Electronic, Ionic
23 Audio and Radio frequency Electronic
24 Power Frequency Electronic, Ionic, Orientation
Match the following
25 Electronic Polarization 10
2
Hz
26 Ionic Polarization 10
6
Hz
27 Orientation Polarization 10
13
Hz
28 Space - Charge Polarization 10
15
Hz 0.5 AN CO 5 Book back

15. Match the following
29 Electronic Polarization Ferrites
30 Ionic Polarization Water molecule
31 Orientation Polarization Ionic crystals
32 Space - Charge Polarization Inert gases
33 ________________ Polarization increases with increase in temperature.
34 ________________ Polarization decreases with increase in temperature.
35 _________________ Polarizations are independent of temperature.
36 ________________ Polarization increases with increase in temperature.
37
The property of certain crystals that exhibit spontaneous polarization in
the absence of an external electric field is known as ________________



38 The internal field is given by the relation __________________
39
________________ equation relates the macroscopic dielectric constant (εr)
with microscopic polarizability (αe).



40
The molecules which have permanent dipoles even in the absence of
electric field is known as ________________.



41
The molecules which do not have permanent dipoles is known as
________________.



42 The long range coulomb force produced by the dipoles is called __________.
2 43 Define dielectrics 2 R CO 5 Book back
44 Define polarization of a dielectric material 2 R CO 5 Book back
45 Name the four polarization mechanisms 2 R CO 5 Book back
46 What is electronic polarization? 2 U CO 5 Book back
47 What is ionic polarization? 2 U CO 5 Book back
48 What is Orientational polarization? 2 U CO 5 Book back
49 What is space charge polarization? 2 U CO 5 Book back
50 What is meant by local field in a dielectric? 2 U CO 5 Book back
51 Distinguish between polar and non-polar molecules. 2 AN CO 5 Book back
52 What are the requirements of good insulating materials? 2 AN CO 5 Book back
5-8
53
Distinguish between electronic, ionic, and orientation polarization.

7 AN
CO 5
Book back
54
Explain electronic polarization and derive an expression for electronic
polarizability.
7 AN
CO 5
Book back

16. 55
Explain ionic polarization and derive an expression for electronic
polarizability.
7 AN
CO 5
Book back
56 Discuss the frequency dependence of Polarization mechanisms. 7 AN CO 5 Book back
57 Discuss the temperature dependence of Polarization mechanisms. 7 AN CO 5 Book back
58 Elaborate the properties of Ferroelectric materials 7 E CO 5 Book back
59 Elaborate the hysteresis of Ferroelectric materials 7 E CO 5 Book back
60 Outline the applications of Ferroelectric materials 7 AN CO 5 Book back
61
Calculate the electronic Polarization of argon atom. Given that ??????
??????=
1.0024 at NTP and N=2.7×10
25
atoms / m
3
7 A
CO 5
Book back
62
A solid contains 5×10
28
atoms / m
3
each with a polarizability of 2×10
−40

Fm
2
. Assuming that the internal field is given by Lorentz formula.
Calculate the ratio of internal field to the external field. ??????
0=8.854×
10
−12
�/??????
7 A
CO 5
Book back
63
The dielectric constant of helium gas at NTP is 1.0000684. Calculate the
electronic polarizability of helium atom if the gas contains 2.7×10
26

atoms / m
3
and hence calculate the radius of helium atom (??????
0=8.854×
10
−12
�/??????)
7 A
CO 5
Book back
64
A solid material has 4×10
28
atoms per unit volume. If it shows an
electronic polarizability of 1.5×10
−40
Fm
2
, then calculate the dielectric
constant of the material.
7 A
CO 5
Book back
65
Sulphur has atomic weight 32 and its density is 2.08g/cm
3
. The
electronic polarizability of Sulphur is 3.5×10
−40
Fm
2
. Considering the
cubic symmetry in Sulphur solid, calculate its relative dielectric constant.
7 A
CO 5
Book back
66
Calculate the percentage of ionic polarizability in sodium chloride which
has the refractive index and static dielectric constant 1.5 and 5.6
respectively.
7 A
CO 5
Book back
67
At a temperature of 27
0
C, the dielectric constant of Sulphur is 3.75 and
the internal field coefficient of Sulphur is γ=1/3. If the density of Sulphur
at 27
0
C is 2050kg/m
3
, then calculate the electronic polarizability of
Sulphur. Given that the atomic weight of Sulphur is 32.
7 A
CO 5
Book back
68
If a dielectric has its dielectric constant as 4 and refractive index as 1.5,
then calculate the ratio of its electronic and ionic polarizabilities.
7 A
CO 5
Book back
69 Outline the applications of dielectric materials 7 AN CO 5 Book back
70
A dielectric material has dielectric constant εr=5 and the square of
refractive index (n
2
) is 2.50. calculate the ratio of electronic to ionic
polarizability for this material.
7 A
CO 5
Book back

17. 71
Elaborate ferroelectric hysteresis. Explain the saturation polarization,
remnant polarization, and coercive field.
7 E
CO 5
Book back
72
What is Orientational polarization? Derive an expression for the mean
dipole moment when the polar material is subjected to an external field.
7 AN
CO 5
Book back
10 -
14
73
Discuss the different types of polarization mechanism and polarizability
involved in dielectric materials.
14 AN
CO 5
Book back
74
Starting with the internal filed expression derive Clausius – Mosotti
relation.
10 AN
CO 5
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75
What is meant by internal field? Obtain expression for internal field
using Lorentz method.
10 AN
CO 5
Book back
76
What is meant by local field in a solid dielectric? Deduce an expression
for the local field for structures possessing cubic symmetry.
10 AN
CO 5
Book back
77
What do you mean by polarization of a substance? Outline different
mechanisms of polarization in a dielectric.
14 AN
CO 5
Book back
78
Discuss the frequency and temperature dependence of different
polarization mechanisms in dielectrics.
10 AN
CO 5
Book back
UNIT V NANOSCIENCE AND NANOTECHNOLOGY
Marks S. No Questions Marks
Level
( BTL)
CO
Type ( book
back/ AU/
others)
0.5 / 1 1 The ratio that decides the efficiency of nanostructures is _____ 0.5 AN CO 6 Book back
2 Carbon makes _________ type of bond with other carbon atoms 0.5 AN CO 6 Book back
3
_____ medicine contains nanoparticles prepared by using biologically
processed metal ores
0.5 AN CO 6 Book back
4 Chemical solution deposition is also known as ____________ 0.5 R CO 6 Book back
5 A Bucky ball is a molecule consisting of ___ carbon atoms 0.5 R CO 6 Book back
6 The word 'nanotechnology' was coined by ____________ 0.5 R CO 6 Book back
7 Nanoscience can be studied with the help of _____ mechanics 0.5 AN CO 6 Book back
8 The color of the Nano gold particles is __________ 0.5 AN CO 6 Book back
9 Quantum dots can be used in _________ 0.5 A CO 6 Book back

18. 10
Electronic devices with at least one dimension having size in nanometer scale
are called ________________.

11
The bandgap of the material increases with decreasing size. Say it True or
False?

12
The phenomenon in which the size reduction of a material leads to
confinement of electron motion which results in the discrete energy levels is
known as _________________.

13
A material with at least one of its dimension in the order of few nanometers
is known as _________________.

14
_______________ is defined as a tubular form of interlocking carbon atoms
linked in hexagonal shapes.

15
The general name for the class of structures made of rolled up carbon lattices
is ___________

16 The number of confined directions in quantum dot is _____ 0.5 R CO 6 Book back
17
When all the three dimension are minimized the resulting structure is
____________
0.5 AN CO 6 Book back
18 Top-down technology refers to nanomaterials as _______ 0.5 AN CO 6 Book back
19 Nanostructures have sizes in between ____________ 0.5 R CO 6 Book back
20
_________________ method produce good quality of carbon nanotubes with
increased yield.

21
Carbon nanotubes have strength 100 times greater than steel. Say it True or
False?

22 ______________ is preferred for preparing metal oxide nanocrystals.
23
The process in which the formation of nanomaterials occurs due to thermally
induced chemical reactions at the surface of a heated substrate is known as
____________________.

24
______________ method can be explored in the fabrication of Nano wires of
metals, semiconductors, and conductive polymers.

25
_____________ are scientific instruments that uses a beam of highly
energetic electrons to examine objects on a very fine scale.

26 Carbon nanotubes were discovered in 1991 by _____________ 0.5 R CO 6 Book back
Match the following

19. 27 Single Walled carbon nanotubes 1 – 2 nm
28 Multi Walled carbon nanotubes 2 – 50 nm
29 Armchair 30
o

30 Zig Zag 0
o
0.5 R CO 6 Book back
31 Chiral structure 0
o
to 30
o

2 32 Outline the methods of producing carbon nanotubes 2 AN CO 6 Book back
33 Define Nanomaterials 2 R CO 6 Book back
34 Define Nanotechnology 2 R CO 6 Book back
35 Outline the applications of carbon nanotubes 2 AN CO 6 Book back
36 Outline the synthesis methods of nanomaterials 2 AN CO 6 Book back
37 Define Quantum confinement 2 R CO 6 Book back
38 What is meant quantum confined structure? 2 U CO 6 Book back
39 What are the types of carbon nanotube structure? 2 U CO 6 Book back
40 Mention any four applications of carbon nanotubes. 2 R CO 6 Book back
41 Define Surface to Volume ratio 2 R CO 6 Book back
5-8
42
Discuss the steps involved in the Sol-gel process for synthesis of
nanomaterials.
7 AN CO 6 Book back
43
Discuss the advantages of Chemical Vapor deposition process for
synthesis of nanomaterials.
7 AN CO 6 Book back
44 Outline the properties of carbon nanotubes. 7 AN CO 6 Book back
45 Discuss the analysis of nanomaterials by X-Ray diffraction. 7 AN CO 6 Book back
46 Discuss the classification of Nanomaterials. 7 AN CO 6 Book back
47
Elaborate the following (i) Quantum dot, (ii) Quantum Wire, (iii)
Quantum well.
7 E CO 6 Book back
48 Outline the day to day live commercial applications of nanotechnology. 7 AN CO 6 Book back
49 Outline the medical applications of nanotechnology. 7 AN CO 6 Book back
50 Elaborate the following : (i) Nanotechnology (ii) Carbon nanotubes. 7 E CO 6 Book back
51
Outline the methods of producing carbon nanotubes and explain any one
of the method with a neat sketch.
7 AN CO 6 Book back
52 Classify nanomaterials and give examples for them. 7 AN CO 6 Book back
53
Outline the characterization techniques of nanomaterials and explain
any one of the method with a neat sketch.
7 AN CO 6 Book back
54
Mention the methods used for synthesis of nanomaterials using Bottom-
up technique and explain any one of them.
7 AN CO 6 Book back

20. 55
Mention the methods used for synthesis of nanomaterials using Top-
down technique and explain any one of them.
7 AN CO 6 Book back
56
Discuss the steps involved in the Physical Vapor deposition for synthesis
of nanomaterials.
7 AN CO 6 Book back
57 Elaborate the lithography technique for synthesis of nanomaterials 7 E CO 6 Book back
58
Elaborate the High-energy ball milling technique for synthesis of
nanomaterials
7 E CO 6 Book back
10 -
14
59 Define carbon nanotubes. Elaborate the types of carbon nanotubes. 14 E CO 6 Book back
60
What are nanomaterials? Outline the physical properties of
nanomaterials.
10 AN CO 6 Book back
61
Discuss the synthesis of nanomaterials using chemical vapor deposition
with a neat diagram
14 AN CO 6 Book back
62
Elaborate Quantum confinement and Quantum structures in
nanomaterials.
14 E CO 6 Book back
63
Elaborate the carbon nanotube structure with their properties and
applications.
14 E CO 6 Book back
64
Enunciate the properties and application of cylindrical large molecules
consisting of a hexagonal arrangement of hybridized carbon atoms
formed by graphene sheets
10 AN CO 6 Book back
65 Elaborate the top-down approach for preparing nanomaterials 10 E CO 6 AU
66 Elaborate the bottom-up approach for preparing nanomaterials 10 E CO 6 AU
67
What are nanomaterials? Outline out the chemical properties of
nanomaterials.
10 AN CO 6 Book back
68 Outline the applications of nanomaterials in various fields. 10 AN CO 6 Book back