Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 8th Semester (Eight Semester) 2018-19 NEE801 Electrical Electronics Engineering Materials Question Paper
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B. TECH.
(SEM VIII) THEORY EXAMINATION 2018-19
ELECTRICAL & ELECTRONICS ENGINEERING MATERIALS
T ime: 3 Hours T 0tal Marks: 100
Note: 1. Attempt all Sections. If require any missing data; then choose suitably.
SECTION A
1. Attempt all questions in brief. 2 x 10 = 20
Draw (112) & (111) planes in simple cubic cell.
Write ohms law for electron theory.
What do you mean by doping in semiconductor?
What is Curie temperature?
Explain Seebeck, Thomson Effect in thermocouple.
Mobility of electrons & holes in intrinsic semiconductor of germanium at room
temperature are 3600 CIIlZ/V-S & l700cm2/V?s. if electrons & holes are equal to
3.2 X 1012 /cm3 , find out conductivity.
rmP-Op?w
g. What is Magnetostriction and its types?
h. Explain Body centered cubic structure (BCC)
i Write composition of Alnico.
_] Explain Metallic bonding with diagram.
SECTION B
2. Attempt any three of the following: 10x3=30
a. Explain the effect of temperature on electrical conductivity of metals. The following
data refer to copper-
Density=8.94 gm/cm3, resistivity=l.73X10'8 Qm; atomic weight = 63.5
Calculate the mobility and average time of collision of electron in the copper.
b. Explain Bragg?s, Law.,X ray of wavelength 1.54 A are used for calculating d200 in Ni
. The re?ection angle is 9.5 degree , what is size of unit cell.
c. Using drift and diffusion current in a semiconductor, find an expression of continuity
equation.
(1. Draw Diagrams giving energy band structure of an Conductor, insulator &
semiconductor. Explain difference in their conductivity?
6. Describe soft and hard magnetic material indicates their composition, property also
draw their B?H curve.
SECTION C
Attempt any one part of the following:
9?
State Ionic, Covalent & Metallic bonds with their characteristics.
Explain Miller indices, write procedure to find it. Also prove that
diooidiiozd111IV6:\/3:\/2 for a simple cubic system.
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4. Attempt any one part of the following:
a. Write short note- Soft Magnetic material, Hard Magnetic material also draw their B?
H curve.
b. Explain Ferromagnetism, Ferri magnetism, Anti ferromagnetism material with their
properties.
5. Attempt any one part of the following:
a. With the help of neat sketches and characteristic curves explain the operation of the
Junction FET.
b. Calculate the drift velocity of electrons & holes in (1) Si (ii) Ge at 300K when
applied electric field is 50V/cm take up = 500 cmz/V?s , pm: 1500 cmZ/V?s for Si , Hp
= 3700 cmZ/V?s , pm: 3600 cmz/V-s for Ge.
9"
Attempt any one part of the following:
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Write short notes on followings:
(i) Fermi surface
(ii) Energy gap
(iii) Energy level
b. Find energy loss per hour in Iron subjected to magnetization 50 0/3 . the iron weight
50 kg & hysteresis loop area 250 joules / m3. Density of iron: 7000 kg/m3
7. Attempt any one part of the following:
a. What is Hall Effect; derive the relation between hall coef?cient and current density.
Assume presence of only one charge carrier.
b. Explain the term superconductivity. Name some of the important superconductivity
elements compound and alloys.
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This post was last modified on 30 January 2020