PH 2161 Important Engineering Physics 2 Anna University Questions Unit Wise



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.