Anna University of Technology Tirunelveli 2009 B.E Engineering Physics Ph23 - -II - Question Paper

ANNA UNIVERSITY TIRUNELVELI
B.E/B.TECH DEGREE EXAMINATION, APRIL/MAY 2009
SECOND SEMESTER
Ph23 - ENGINEERING PHYSICS-II
(REGULATION 2008)


PART A (10X2=20 MARKS)


1. State widemann – franz legal regulations.

2. The Fermi energy of silver is 5.51 eV. What is the avg. energy of a free electron at 0k?

3. the resistivity of intrinsic semiconductor germanium at 300k is 0.47 ohm .m. if the electron and hole mobilities are 0.38 and 0.18 m^2 V^-1s^-1.calcualte the intrinsic carrier density at 300k.

4. describe hall effect?.

5. What is Bohr magneton?

6. Superconductors tin has a critical temperature of 3.7k at zero magnetic field and a critical field of 0.0306T at 0k.find the critical magnetic field at 2k.

7. How temperatures effect the polarization of dielectrics?

8. provide any 2 applications of ferroelectric materials.

9. Name any 2 examples of ferroelectric materials.

10. elaborate carbon nano tubes?




PART B- (5 X 16=80)

11.
i. starting with the classical free electron theory of metals find an expression for electrical and thermal conductivity and hence prove wiedemann – franz legal regulations..


Or

12
i. describe Fermi energy.
ii. Starting with the density of energy of energy states find an expression for Fermi energy of the electron at absolute 0k..
iii. find an expression for avg. energy of an electron at T=0k.


13.
i. find an expression for intrinsic carrier concentration in an intrinsic semiconductor.

ii. How will you determine the energy gap of an intrinsic semiconductor?

Or


14.
i. find an expression for hall coefficient
ii. How will you measure hall coefficient experimentally?
iii. define any 2 applications of hall effect..


15.
i. define the Ferro magnetic domain theory in detail and how will you account hysteresis of Ferro magnetic material based on domain theory.




Or


16.
i. explain the kind I and kind ii super conductors.

ii. define the BCS theory of super conductivity.




17.
i. define the various kinds of polarization.
ii. find an expression for electric and ionic polarization in dielectrics.



Or


18.
I. Starting with the internal field in a dielectric. find clausius-mossotti formula.
ii. explain the effect of frequency on polarization.


19. Write short note on:
i. Metallic glasses?
ii. Shape memory alloys.


Or


20.
i. elaborate nano materials? define any 2 methods of production of nano materials. explain the application of nano materials.

Earning:   Approval pending.