### 182202 (PH 2161) — ENGINEERING PHYSICS – II Second Semester B.E./B.Tech.Degree Examinations, JUNE 2010 question paper

Reg. No. :
B.E./B.Tech. DEGREE EXAMINATION, JUNE 2010
Second Semester

PH 2161 — ENGINEERING PHYSICS – II
(Common to all branches)

(Regulation 2008)
Time : Three hours Maximum : 100 Marks
PART A — (10 × 2 = 20 Marks)

1. Mention the demerits of classical free electron theory.
2. Calculate the Fermi energy of copper at 0°K if the concentration of electron is
8.5 × 1028m–3.
3. Distinguish between n-type and p-type semiconductors.
4. Mention the uses of Hall Effect.
5. The transition temperature for a superconducting material is 3.7 K at zero
magnetic field and critical field is 0.0306 A/m at 0°K. Calculate the critical
field at 2°K.
6. Define anti Ferraro magnetism. Mention two materials that exhibit
anti Ferraro magnetism.
7. What is ionic polarization? Write an expression for ionic polar isability.
8. State the properties of Ferraro electric materials.
9. Explain shape memory effect.
10. Name the types of metallic glasses and mention few metallic glasses.

PART B — (5 × 16 = 80 Marks)

(Planck's constant = 6.63 × 10–34 Js, Boltzman constant = 1.38 × 10–23 JK–1,
Mass of the electron = 9.1 × 10–31 kg, Charge of electron = 1.6 × 10–19 coulomb)

11. (a) (i) Define drift velocity and relaxation time. (Marks 2)
(ii) Derive expressions for both electrical conductivity and thermal
conductivity of electrons in metal. (Marks 7 + 7)
Or
(b) (i) Define density of states. (Marks 2)
(ii) Derive an expression for the density of states in a metal. (Marks 10)
(iii) A conducting rod contains 8.5 × 1028 electrons per cubic meter.
Calculate the electrical conductivity and mobility of electron, if the
collision time for scattering is 2 × 10–14 sec. (Marks 4)
12. (a) (i) Derive an expression for the concentration of electrons in the
conduction band of an intrinsic semiconductor. (Marks 10)
(ii) With necessary theory, describe the method of determining the
band gap of an intrinsic semiconductor. (Marks 6)
Or
(b) (i) What is Hall effect? (Marks 2)
(ii) Give the theory of Hall effect. (Marks 8)
(iii) The density of silver is 10.5 × 103 kg/m3 . The atomic weight of silver
is 107.9. Assume that each silver atom provides one conduction
electron. The electrical conductivity of silver at 20°C is
6.8×107 -1 -1 m . Determine the carrier concentration and mobility
of electrons, if N = 6.02 × 1026 atom/k. mol. (Marks 6)
13. (a) (i) Give the Weiss theory of ferromagnetism and derive an expression
for its susceptibility. (Marks 8)
(ii) Describe the structure, properties and applications of ferrite. (Marks 8)
Or
(b) (i) Distinguish between soft and hard magnetic materials. (Marks 5)
(ii) Explain Meissner effect. (Marks 3)
(iii) Describe Type I and Type II superconductors. (Marks 8)
14. (a) (i) Define local field in a dielectric. (Marks 2)

(ii) Derive an expression for the local field in a dielectric for a cubic
structure. (Marks 10)
(iii) Deduce Clausius-Mosotti relation. (Marks 4)
Or
(b) (i) Discuss in detail the different dielectric breakdown mechanisms.
(10)
(ii) Describe the frequency dependence of polarization of a dielectric
material. (Marks 6)
15. (a) (i) What are metallic glasses? How are they prepared? (Marks 2 + 4)
(ii) Describe their properties and application. (Marks 5 + 5)
Or
(b) (i) What are nano-phase materials? (Marks 2)
(ii) Describe the method of producing nano materials using
(1) chemical vapor deposition method (Marks 3)
(2) plasma assisted deposition method. (Marks 3)
(iii) Write a short note on carbon nano tubes. (Marks 8)

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