LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
FIFTH SEMESTER – NOVEMBER 2003
PH 5402 / PHY 402 – MATERIALS SCIENCE
12.11.2003 Max. : 100 Marks
1.00 – 4.00
PART – A
Answer all the questions (10 x 2 = 20 marks)
- How will you classify the engineering materials on the basis of the major areas of applications?
- Write a note on the structure-property relationships in materials.
- Discuss the steps involved in the formation of Burger’s circuit for dislocation.
- Determine the Miller indices of a plane that makes intercepts of 4x, y and 2z.
- Give the formula for measuring the Young’s modulus of composite materials.
- Explain the phenomenon of “work hardening” of engineering materials.
- What is the principle of the NDT method based on photoelastic phenomenon.
- How does the intrinsic break down of a dielectric material take place?
- Calculate the relative dielectric constant of a barium titanate crystal, which, when inserted in
a parallel plate condenser of area 8 mm X 8 mm and distance of separation of 1. 8 mm gives a capacitance of 0.05 mF
- List the advantages of scanning electron microscopie (SEM).
PART – B
Answer any FOUR questions (4 x 7.5 = 30)
- Discuss, how the physical properties of materials are influenced by the variation in bonding character.
- What is meant by a symmetry operation? Explain the different types of symmetry elements of a crystalline solid.
- What are true stress and true strain? Using the tensile stress-strain curve for a ductile material, obtain the power relationship connecting s and e.
- Explain (I) electrical resistance (ii) tribolectric effect and (iii) thermoelectric effect techniques adopted for NDT.
- Give the theory of ferroelectrics as applied to Barium Titanate. Mention the applications of ferroelectric materials.
-2-
PART – C
Answer any FOUR questions (4 x 12.5 = 50)
- What is meant by polarization?
Discuss the various polarization processes with necessary diagrams and hence obtain the expression for the total polarization of a material.
- Draw a schematic diagram of an Electron Microscope and explain its working.
- a) Discuss the essential characteristics of covalent bonding with relevant examples.
(5 marks)
- Explain the necessary steps involved in the formation of ionic bond and obtain the expression for the potential energy of the system of bond forming atoms. (7.5 marks)
- a) State and explain Bragg’s low of x-ray diffraction (5 marks)
- Describe with a neat sketch, the powder XRD method of determining crystal structure.
- Discuss the atomic model of elastic behavior with necessary figure and derive the relations connecting y,