# Dec 2010 BE SPHX1001 Physics of Materials Sathyabama University

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SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act, 1956)

Course & Branch: B.E/B.Tech-Common to ALL Branches
Title of the Paper: Physics of Materials                 Max. Marks: 80
Sub. Code: SPHX1001                                           Time: 3 Hours
Date: 06/12/2010                                                    Session: FN
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PART - A                (10 X 2 = 20)

1.     What is Lorentz number? What is its value?

2.     A superconducting tin has a critical temperature of 3.7K at zero magnetic fields and a critical field of 0.0306 Tesla at 0K. Find the critical field at 2K.

3.     Mention the materials used as magnetic data storage.

4.     What is dielectric breakdown?

5.     Define active non linear materials.

6.     What is meant by colour centre?

7.     Mention the factors which affect the properties of composite materials.

8.     Define two way shape memory allory.

9.     State Bragg’s law and its importance.

10.   On what factors the resolution of an electron microscope depends?

PART – B                       (5 x 12 = 60)

11.   What are the postulates of the classical free electron theory? Derive the mathematical expression for the electrical conductivity and thermal conductivity of metal.
(or)
12.   (a) What is Josephson effect? Explain the dc and ac Josephson effect.
(b) Explain type I and type II superconductors with examples.

13.   (a) Explain the domain theory of ferromagnetism.               (8)
(b) Distinguish between hard and soft magnetic materials. (4)
(or)
14.   (a) What is internal field in solid dielectrics? Derive a mathematical expression for the internal field in solid dielectrics.
(10)
(b) Calculate the polarization produced in a dielectric medium of dielectric constant 6, when subjected to electric field of 100 V/m.
(2)

15.   (a) What is luminescence? Explain how photoluminescence take place in characteristic luminescent materials.                        (8)
(b) Write a short note on excitons.                                                 (4)
(or)
16.   (a) Explain how the frequency doubling is achieved using a non linear materials, with suitable illustrations.                             (8)
(b) Write a short note on optical mixing.                               (4)

17.   (a) What is meant by shape memory effect?                                 (3)
(b) Explain the following terms in shape memory alloys.     (9)
(i) Hysteresis curve
(ii) Super elasticity
(iii) Thermo mechanical behaviour
(or)
18.   (a) Describe how ceramic particles are processed to produce a solid product in advance ceramics.                                         (8)
(b) Give an account of composite materials.                                 (4)

19.   (a) Explain how the x-ray diffraction is used to determine the crystal structure.                                                                         (9)
(b) What are the merits and demerits of neutron diffraction? (3)
(or)
20.   Explain the principle, construction and working of scanning electron microscope.