Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 8th Semester (Eight Semester) 2017-18 NEE 801 Electrical And Electronics Engineering Material Question Paper
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B TECH
(SEM?VIII) EVEN SEM.THEORY EXAMINATION, 2017-18
ELECTRICAL AND ELECTRONICS EN GINEERIN G MATERIAL
T ime: 3 Hours Max. Marks: 100
Note: Attempt all sections. Assume missing data suitably, if any.
SECTION ? A
1. Attempt all parts of the following: (10*2=20)
(a) Distinguish between primitive cell and unit cell.
(b) Define Miller indices of a plane.
(c) Explain the terms space lattice and coordination number.
(d) Show that for simple cubic system is d100:d110:d111:: \/6: V3: V2
(e) Define the terms energy band and forbidden bands.
(f) Explain the Seebeck effect.
(g) The lead material works as superconductor at a temperature of Tc=7.26K. If the constant
characteristics of the lead material at 0K is Ho=8x105A/m. calculate the magnetic field in
the lead at 5K.
(h) Explain the Peltier effect.
(i) What is Magneto-striction?
(i) Explain the term Drift and continuity equation.
SECTION ? B
2. Attempt any three parts of the following: (3*10=30)
(a) State and explain ?Bragg's Law?. X-rays with wavelength of 0.58A are used for
calculating dzoo in nickel. The re?ection angle is 9.50. What is the size of unit cell?
(b) Explain the Langevin?s theory of Diamagnetism 0r Para?magnetism.
(c) Explain the working principle of a MOSFET. Discuss also the types of MOSFET and
their working.
(d) Show that the conductivity of intrinsic semiconductors are given as :
(Si = me (He + uh), The symbols having their usual meanings.
(e) Explain in brief the zone theory of solids.
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SECTION ? C
Answer all questions in this section.
3.
Attempt any one parts of the following: (1*10=10)
(a) Show that the Hall coefficient is given as for semiconductor materials:
RH = ? i and OH = tan?1(ue~Bz) respectively.
the symbols having their usual meanings.
(b) What is Hall Effect? The resistivity of a doped silicon crystal is 9.23x10'3 Q-m and the
Hall coefficient is 3.84x10'4 m3c'1. Assuming that the conduction is by a single type of a
charge carrier calculate the density and mobility of the carrier.
Attempt any one parts of the following: (1*10=10)
(a) Show that the resistivity of the metal is given by :
_ m
P ? nezr
the symbols having their usual meanings.
(b) Sketch the B-H loop of a ferromagnetic material.
Attempt any one parts of the following: (1*10=10)
(a) Explain relative permeability. Show that the relative permeability as Mr = 1 + x Where x
is the magnetic susceptibility.
(b) A diffraction pattern of a cubic crystal of lattice parameter a=3.16A is obtained with
monochromatic X-ray beam of wavelength 1.54 A. The first line on this pattern was
observed to have 6 =20.3?.
Attempt any one parts of the following: (1*10=10)
(a) What are ferrites? Give some applications where ferromagnetic materials are used.
Explain ferrimagnetisms.
(b) Explain the concept of Hysteresis loss and eddy current loss in ferromagnetic material.
Attempt any one parts of the following: (1*10=10)
(a) Explain the superconductivity with Meissner Effect. Determine the temperature co-
ef?cient of resistance of material used in a resistor if the resistance at 25?C is 509 and at
70?C is 57.2 9.
(b) Explain thermal conductivity and obtain an expression for coef?cient of thermal
conductivity.
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This post was last modified on 30 January 2020