Hall Ticket No Question Paper Code: AHS006
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
B.Tech I Semester End Examinations (Regular) December, 2017
Regulation: IARE R16
ENGINEERING PHYSICS
Common for (CSE IT ECE EEE)
Time: 3 Hours Max Marks: 70
Answer ONE Question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
UNIT I
1. Define Polarizability and derive an expression for electronic polarizability.
A solid elemental dielectric with density 3 × 1028atoms/m3 shows electronic polarizability of
farad m2.Assuming internal electric field to be Lorentz field, calculate the dielectric constant
of the material.
2. Define magnetic moment. Explain the origin of magnetic moment in dia and para magnetic
substances.
The magnetic field intensity in a piece of ferric oxide is 106 amp/m. If susceptibility of the
material is 1.5 × calculate the magnetization of material.
UNIT II
3. What are Einstein's coefficients? Explain the main components of any laser system.
Find the ratio of population of two energy levels in a laser if the transition between them produces
light of wavelength 694.3 nm. Assume the ambient temperature to the 27C.
4. Describe the construction and working of semiconductor diode laser with energy level diagram.

A ruby laser emits a pulse of 20 ns duration with average power per pulse being 100 KW. If the
numbers of photons in each pulse is 6.98 x 1015. Calculate the wavelength of photons.
UNIT III
5. Explain briefly bottom-up fabrication of nanomaterial by sol-gel method.
Explain briefly characterization of nonmaterial by TEM.
6. What are carbon nanotubes. Discuss the important applications of nanotechnology.
Explain briefly quantum dots of the nanoworld.
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UNIT IV
7. State the deBroglie hypothesis. Describe Davisson and Germer's experiment for confirmation of
deBroglie hypothesis with neat sketch.
Find the kinetic energy and group velocity of an electron with deBroglie wavelength of 0.2 nm.

8. State the Heisenberg's uncertainity principle. Obtain an expression time independent Schrodinger
wave equation in one dimension.
A particle of mass 0.65 MeV/c2 has a kinetic energy of 80 eV. Calculate the deBroglie wavelength
and group velocity.
UNIT V
9. Write short notes on direct and indirect band gap semiconductors.
Explain the effect of temperature and dopant on the Fermi level in a semiconductor.
10. What are the classification of solids. Derive the expression for thermal equilibrium hole
concentration in an semiconductor.
The energy gap of Ga As is 1.42 eV. The effective masses of electrons and holes are:0.067 m0 and
0.48 m0 respectively. Calculate the concentration of holes at 300 K.