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

Answer ALL Questions

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 antiferromagnetism. Mention two materials that exhibit

antiferromagnetism.

7. What is ionic polarisation? Write an expression for ionic polarisability.

8. State the properties of ferroelectric materials.

9. Explain shape memory effect.

10. Name the types of metallic glasses and mention few metallic glasses.

Question Paper Code: E3165 4

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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. (2)

(ii) Derive expressions for both electrical conductivity and thermal

conductivity of electrons in metal. (7 + 7)

Or

(b) (i) Define density of states. (2)

(ii) Derive an expression for the density of states in a metal. (10)

(iii) A conducting rod contains 8.5 × 1028 electrons per cubic metre.

Calculate the electrical conductivity and mobility of electron, if the

collision time for scattering is 2 × 10–14 sec. (4)

12. (a) (i) Derive an expression for the concentration of electrons in the

conduction band of an intrinsic semiconductor. (10)

(ii) With necessary theory, describe the method of determining the

band gap of an intrinsic semiconductor. (6)

Or

(b) (i) What is Hall effect? (2)

(ii) Give the theory of Hall effect. (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 11 −−Ω m . Determine the carrier concentration and mobility

of electrons, if N = 6.02 × 1026 atom/k. mol. (6)

13. (a) (i) Give the Weiss theory of ferromagnetism and derive an expression

for its susceptibility. (8)

(ii) Describe the structure, properties and applications of ferrites. (8)

Or

(b) (i) Distinguish between soft and hard magnetic materials. (5)

(ii) Explain Meissner effect. (3)

(iii) Describe Type I and Type II superconductors. (8)

14. (a) (i) Define local field in a dielectric. (2)

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(ii) Derive an expression for the local field in a dielectric for a cubic

structure. (10)

(iii) Deduce Clausius-Mosotti relation. (4)

Or

(b) (i) Discuss in detail the different dielectric breakdown mechanisms.

(10)

(ii) Describe the frequency dependence of polarisation of a dielectric

material. (6)

15. (a) (i) What are metallic glasses? How are they prepared? (2 + 4)

(ii) Describe their properties and application. (5 + 5)

Or

(b) (i) What are nano-phase materials? (2)

(ii) Describe the method of producing nano materials using

(1) chemical vapour deposition method (3)

(2) plasma assisted deposition method. (3)

(iii) Write a short note on carbon nano tubes. (8)

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