Engineering Physics II - Question paper June 2010

                                    Anna University, Chennai
                   B.E./B.TECH  DEGREE EXAMINATION, JUNE 2010
                             PH 2161 - ENGINEERING PHYSICS  II
                                        (Regulation 2008)
                  

                                      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 polarization? 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.

                             PART B — (5 × 16 = 80 Marks)


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 meter.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 Ω^-1 m^-1. 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)
           (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 polarization 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)