Anna University Chennai 2005 B.E Electronic Instrumentation & Control Engineer /B.TECH:Material science - Question Paper

B.E/B.TECH.DEGREE exam ,NOV/DEC 2005
Second semester,E I
Material science



Time taken : 3Hrs
Maximum marks : 100

PART A ( 10 X two =20)

1. compute the atomic packing factor of simple cubic system

2.Indicate (110) plane and [110] direction in the simple cubic unit cell

3.Fermi energy of sodium is 3.2 ev.Calculate the fermi velocity

4.Mention the criticle temperature of mercury and YBa2Cu3O7

5.What are compound semiconductors?Mention 2 examples

6.What is hell effect?

7.What is Bohr magneton ?Obtain its value

8.What is meant by dielectric poarization?

9.Mention the optical properties of metals.

10.What is meant by photoconductivity?

PART B ( five X 16 =80)

11(i) Mention the different crystal systems.

(ii)State the bragg's legal regulations of diffraction

(iii) discuss in detail different crystal imperfections

(iv) discuss how miller indices of a plane is established.

12 (a) (i) The electrical resistivity and thermal conductivity of copper at 20 degree C are 1.72 X 10 ^ -8 ohm meter and 368 W /m/k respectively.Dtermine the lorentz number.

(ii) Distinguish ranging from metals,semiconductors and insulators on the basis of band gap

(iii) Derive an expression for the fermi energy of a system of free electrons

OR

(b) (i)Mention the physical properties of metals

(ii)Briefly explain the drawbacks of classical free electron theory of metals

(iii)What is meissner effect?

(iv) provide a note on the applications of superconductors.

13 (a) (i)What are extrinsic semiconductors ?Draw the energy band daigram of extrinsic semiconductors

(ii)Explain in detail the variation of carrier concentration with temperature.

(iii)Give the expression for the carrier concentration in intrinsic semiconductors

OR


(b) elaborate the applications of hall effect ?Obtain an expression for the hall coefficient for ntype semiconductors.Describe the experimentalsetup for the measurement of hall voltage.

14 (a)Discuss in detail the various kinds of magnetic materials .With neat sketch discuss the magnetic hysterisi charecteristics of ferromagnetic materials on the basis of domain theory

OR

(b) discuss in detail the different polarization mechanism in dielectrics .Comment on the effect of frequency on them.Discuss the different dielectric breakdown mechanisms.

15 (a)Distinguish ranging from phosphoresence and fluoroscence.Describe the different phophor materials used in CRO screens .Mention their applications

OR

(b) (i) elaborate F centers and V centers

(ii)Briefly discuss how they are genrated.

(iii) What is thermography?Meniton its applications.

Earning:   Approval pending.