Anna University Trichy 2009 B.E Engineering Physics Ph 1152--ii - Question Paper

B.E/B.TECH DEGREE EXAMINATION, JUNE/JULY 2009
SECOND SEMESTER
PH 1152-ENGINEERING PHYSICS-II
(REGULATION 2008)


PART A (10X2=20 MARKS)


1. How classical free electron theory failed to account for specific heat of solid?

2. describe Fermi energy level and provide its importance.

3. provide any 2 differences ranging from elemental and compound semiconductors

4. Draw the diagram to show variation of Fermi level with temperature in the cases of p-type semiconductor for high and low doping level.

5. Mention the energies involved in domains of ferromagnetic materials.

6. What is cooper pair of electrons?

7. describe dielectric loss.

8. elaborate ferroelectric materials?.

9. Write the merits of metallic glasses as transformer core

10. elaborate the various structures of carbon nanotubes?




PART B-(5 X 16=80)

11.
i. Derive an expression for the electrical conductivity of metal.
ii. The density and atomic weight of copper are 8900 kgm^-3 and 63.5.the relaxation time of electron in Cu at 300k is 10^-14s.assuming that every copper atom contributes 1 free electron, compute the electrical conductivity of copper.

Or

12
i. describe density of states.
ii. Derive an expression for the density of states in a metal.
iii. A conducting rod contains 8.5 x 10^28 electrons Or


14.
i. What is Hall Effect? per cubic meter. compute the
electrical conductivity and mobility of electrons, if the collision time for
scattering is two x 10^-14 sec.


13.
i. Derive an expression for the concentration of electrons in the conduction band of
an intrinsic semiconductor.

ii. With necessary theory, define the method of determining the band gap of an
intrinsic semiconductor.


ii. provide the theory of Hall Effect.
iii. The density of silver is 10.5 x 10^3 kg/m^3.the atomic weight of silver is 107.9.
presume that every silver atom provides 1 conduction electron. the electrical
conductivity of silver at 20c us 6.8 x 10^7 ohm^-1m^-1.determine the carrier
concentration and mobility of electrons, if N=6.02 x 10^26 atom/k. mol.


15.
i. provide the Weiss theory of ferromagnetism and derive an expression for its susceptibility.

ii. define the structure, properties and applications of ferrites.


Or


16.
i. Distinguish ranging from soft and hard magnetic materials.

ii. discuss Meissner effect.

iii. define kind I and kind ii superconductors.


17.
i. describe local field in a dielectric.
ii. Derive an expression for the local field in a dielectric for a cubic structure.
iii. Deduce Clasius - mosatti relation.


Or


18.
i. explain in detail the various dielectric breakdown mechanisms.
ii. define the frequency dependence of polarization of a dielectric material.


19.
i. elaborate metallic glasses? how are they prepared?
ii. define their properties and application.


Or


20.
i. elaborate nano-phase materials?
ii. define the method of producing nano materials using
a. Chemical vapour deposition method
b. Plasma assisted deposition method.

iii. Write a short note on carbon nano tubes.

Earning:   Approval pending.