UNIT-CONDUCTING MATERIALS
Part – A
1. Define mobility
give its unit.
2. Define Drift
velocity.
3. What are the
drawbacks of classical free electron theory.
4. Define Mean free
path.
5. Define Collision
Time.
6. Define Electrical
Conductivity.
7. Define Thermal
Conductivity.
8. State
Wiedemann-Franz law.
9. Define Lorentz
number.
10. Define relaxation
time of an electron.
11. What is Planck’s
Hypothesis.
12. State Planck’s
radiation – law.
13. Define
Compton-effect.
14. Write Plack’s
radiation formula.
15. Write down
Schroedinger time independent and time dependent wave
equation with symbol.
16. Give the physical
significance of wave function.
17. What are the
eigen value and eigen function ?
18. Write Fermi-Dirac
distribution formula.
19. Define Fermi
level and Fermi Energy with its importance.
20. How does Fermi
function varies with temperature
21. What is work
function.
22. what are bound
and free electron.
23. For Copper the
relaxation time is 10-14 seconds. The free electron density is
24. 2 × 1028/ m3.
Calculate its electrical conductivity.
25. What is the
probability of an electron bring thermally promoted to the
Conduction band in
silicon (Ec= 1.07 eV)
at 25°C ?
26. Give the
expression for change in wavelength of a scattered X-ray Photon.
Part-B
27. Derive the
electrical conductivity of a metal based on classical free electron
theory.
28. Derive the
thermal conductivity of a metal based on classical free electron
theory.
29. State and Prove
Wiedemann-Frantz law.
30. What is Compton
effect ? Give the theory of Compton effect and Show that
the Compton shift
Δλ = h . (1 – cosθ)/m0c.
31. Explain the
application of Schrodinger wave equation to a one Dimensional
Potential well.
32. Derive Time
independent Schroedinger wave equation and hence deduce the
time dependent
Schroedinger
equation.
33. Describe the
energy band theory of solids with the help of neat band
diagram. Distinguish
between metals
insulator and semiconductor on the basis of band theory.
34. Derive the
expression for Planck’s theory of Black body radiation.
Unit- II SEMI CONDUCTORS MATERIALS
Part – A
35. What are compound
semiconductors? Give examples.
36. Why the
conductivity of a semiconductor increase with temperature?
37. What is an
intrinsic-semiconductor?
38. Why do masses of
electron and hole vary in semi-conductor?
39. What is an
extrinsic-semiconductor?
40. Define Fermi
level in the case of semiconductors. Mention its position in
intrinsic and extrinsic
semiconductors at 0˚K.
41. Calculate the
wavelength of radiation emitted by LED made up of a semi-
Conducting
material with Band
gap energy (Eg) 2.8 eV.
42. What is an N-type
semi-conductor? Give example.
43. What is an P-type
semi-conductor? Give example.
44. How does the
Fermi-level change with temperature in extrinsic
semiconductors ?
45. What is meant by
band gap in solids ? Mention its units.
46. What is Hall
effect?
Part-B
47. Obtain and
expression for the carrier concentration in an intrinsic
semiconductor.
Calculate the
intrinsic concentration of charge carriers at 300˚K, given me=
0.12mo,
48. Discuss
electrical conductivity of intrinsic semi-conductor and hence derive
an expression
for the band gap
energy.
49. Derive an
expression for carrier concentration in an N-type semiconductor
(Density of
electrons in the
conduction band).
50. Derive an
expression for the density of holes in the valence band of an Ptype
semi
conductor.
51. Discuss the
variation of Fermi-level with temperature in N-type and P-type
semi conductors.
52. Discuss the
variation of carrier concentration with temperature for N-type
and P-type
semiconductors.
53. Explain the
determination of Hall co-efficient, carrier concentration and
mobility of charge
carriers of a semi
conductor.
UNIT-3 MAGNETIC AND SUPERCONDUCTING MATERIALS:
PART-A
54. What is magnetic
material?
55. Define magnetic
Induction give its unit
56. Define magnetic
field Intensity give its unit
57. Define free space
permeability
58. Define Magnetic
permeability
59. Define relative
permeability
60. Define Intensity
of magnetization
61. What is magnetic
susceptibility
62. .What is the
relationship between relative permeability and magnetic
susceptibility?
63. State any four
properties of Dia magnetic substance
64. State any four
properties of Para magnetic substance
65. State any four
properties of Ferro magnetic substance
66. Define domain
67. Distinguish
between Ferro magnetic and antiferro magnetic
68. What is Curie
temperature?
69. Define Bohr
magnetron
70. Define Magnetic
moment
71. Define Hysteresis
72. Distinguish
between hard magnetic materials and soft magnetic material
73. Define GMR effect
74. Write a short
note on bubble memories
75. Distinguish
between RAM and ROM
76. Define Transition
temperature
77. Define Super
conductivity
78. Distinguish
between Type-I and Type-II superconductor
79. What is Meissner
Effect?
80. Define Isotope
effect
81. What is high
temperature superconductor? give example
82. What is SQUIDS?
83. What is magnetic
levitation?
84. How are different
magnetic materials classified?
85. What are the
different sources of permanent magnetic moment?
86. What is curie –Weiss
Law?
87. Give the
significance of Curie Weiss law
88. What is
Heisenberg theory of ferromagnetism?
89. What is meant by
Hysteresis loss?
90. Define Energy
product of magnetic material.
91. What are the
applications of ferrites?
92. Why are ferrites
advantageous for use as transformer cores?
93. Explain the
importance of the magnetic materials
94. What are the five
basic parts of a digital magnetic tape system?
95. How is earth
garnets used for data storage?
Part_B
Magnetic materials:
96. What are
diamagnetic and paramagnetic susceptibilities of material? Discuss
the
temperature variation
of their susceptibility.
97. Discuss Langevin
theory of a paramagnetic gas and obtain an expression for
the
paramagnetic
susceptibility of the gas. What are the main drawbacks of the
theory?
98. Derive an
expression for the magnetic moment M of a paramagnetic solid
on the basis of
quantum theory.
99. What is Ferro
magnetism? Explain the reason for the formation of domain
structure in
ferromagnetic
material and how the hysteresis curve is explained on the basis of
the domain
theory.
a) Classify the
magnetic materials on the basis of their spin.
b) What are
ferromagnetic domains?
c) Discuss Weiss
theory of Ferro magnetism
100. D) What are its
merits and demerits?
101. Give an account
of Weiss theory of Ferro magnetism and show from the
post of
Langevin function
spontaneous magnetization exists below the Curie
temperature and
vanishes
above the Curie
temperature.
102. Explain the
domain theory of Ferro magnetism. Using that how will you
explain the
properties of Ferro
magnetic materials?
103. Draw a B-H curve
for a Ferro magnetic material and identify retentivity
and
coercitive field on
the curve.
104. .Write an essay
on different magnetic storage media. What are their
relative merits
and demerits?
105. In detail
explain how data are stored in magnetic materials. What are the
functions of
writing and reading
heads? How are they designed?
106. What are hard
and Soft magnetic materials compare their properties Give
example.
107. Discuss the
phenomenon of antiferromagnetism.how does an anti
ferromagnetic
substance differ from
a diamagnetic substances
SUPERCONDUCTING MATERIALS:
108. Give the
difference between type-I and type-II superconductor.
109. Explain the
superconducting phenomena. What are its properties? What are
in
application?
110. Write an essay
on superconducting materials and its applications. What is
the new
development?
111. What are high Tc
superconductors? Give four examples.
112. Explain the
following
113. Meissner effect
114. Explain the
effect of Isotopes on superconductors
115. What is SQUID?
116. Explain BCS theory
with a special note on copper pairs
117. Give four
medical application of superconductors
118. Explain Magnetic
levitation
Unit_4 DIELECTRIC
MATERIALS:
Part-A
119. Define electric
polarization
120. Compare active
and passive dielectrics
121. Define
electronic polarization.
122. What are the
differences between polar and non polar molecules?
123. Define local
field.
124. What is meant by
dielectric loss and loss tangent? Why it occurs?
125. What is meant by
dielectric breakdown and dielectric strength?
126. Explain
electrochemical breakdown in dielectric.
127. What are
dielectric materials? Give its properties.
128. Define
dielectric constant
129. Define
polarization vector and electric displacement vector
130. Define Ionic
polarizations
131. Define Space
charge polarization
132. Define
orientation polarization.
133. What is the
microscopic polarization mechanism involved in dielectric
polarization
134. Compare the
electronic and orientation polarization.
135. What is effect
of frequency of an a.c field on polarization?
136. What is the
effect of temperature on polarization?
137. What are the
different breaks down mechanisms that occur in a dielectric
material?
138. Discuss the
discharge and defect breakdown in dielectrics.
139. What are the ways
in which the dielectric breakdown can be minimized?
140. Give any four
applications of dielectric in transformer,
141. Write any four
applications of dielectrics in capacitors/
142. What is meant by
electric susceptibility?
143. List out of
frequency dependence of polarization
144. Write a note on
temperature dependence of polarization?
Part-B
145. Discuss in
detail the various dielectric breakdown mechanisms.
146. Deduce Clausius
Mosotti equation and explain its use in predicting the
dielectric
constant of solids
147. Derive an
expression for the orientation polarizability
148. What is meant by
polarization in dielectric? Arrive at the relation between
the
dielectric constant
and atomic polarizability.
149. Show that the
imaginary part of the dielectric constant accounts for a
condenser being
lossy.
150. Explain the
different types of polarization mechanisms involved in a
dielectric
material
151. What is meant by
local field in a dielectric and how is it calculated for a
cubic
structure/deduce the
clausius Mosotti equation
152. Write a short
note on dielectric loss and breakdown mechanism and
application of
dielectric materials
UNIT-5 MODERN ENGINEERING MATERIALS:
PART-A SHORT ANSWERS:
153. What are
metallic glasses?
154. What is the
advantage of using metallic glasses as transformer core
material?
155. Name any four
applications of metallic glasses.
156. What are shape
memory alloys?
157. What are the
merits and demerits of SMA?
158. What are nano
phase materials?
159. Name any four
methods employed to produce nano phase materials.
160. What is meant by
Super plasticity?
161. Define Nano
technology
162. Define quantum
confinement
163. State any four
properties of nano phase materials
164. What are the
type’s carbon nano tubes?
165. What is meant by
glass transition temperature?
166. What do you
understand by the term Quenching?
167. What are the
types of Met glasses?
168. Mention any four
properties of met glasses?
169. List out any
four recent applications of nano materials
170. What is
transformation temperature?
171. What do you
understand by Martensite and Austenite Phases?
172. Define pseudo
elasticity.
173. What are the
properties of SMA?
174. What are the
types of SMA?
175. Give any four
application of SMA.
Part-B
176. What are nano
phase materials? Explain how the physical properties vary
with
geometry
177. Give the concept
properties and applications of metallic glasses.
178. Explain the
various technique used to prepare nano phase materials
179. How are metallic
glasses prepared? Explain how the melt spinner device
can be used
to produce metallic
glasses.
180. Give the
properties and applications of nano phase materials
181. What is meant by
SMA? Explain its working.
182. Give the
characteristics and applications of shape memory alloys.
183. Explain the
various techniques to produce carbon nano tubes.
184. Give the properties and application
of carbon nano tubes.