LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – PHYSICS

FG 43

FOURTH SEMESTER – APRIL 2008

PH 4957 – CRYSTAL PHYSICS

 

 

 

Date : 23/04/2008            Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

PART A

Answer ALL questions:                                                                 10 x 2 = 20 marks

1. Outline the four stages involved in the formation of a stable nucleus
2. How is a primary nucleation different from secondary?
3. On the basis of phase transitions, mention the different methods of crystal growth.
4. State the vital characteristics involved in the choice of the solvents.
5. Mention the experimental conditions of hydrothermal growth method.
6. List any four properties that are taken into account in the choice of flux.
7. Draw the experimental setup for AAS and label the parts.
8. Which region of the electromagnetic spectrum is known as the ultraviolet region?
9. Distinguish between DTA and DSC techniques.
10. Mention few physicochemical parameters that could be measured by thermal analysis.

PART B

Answer any FOUR questions:                                                      4 x 7.5 = 30 marks

1. Give the classical theory of nucleation and discuss the effects of soluble impurities of nucleation.
2. Draw the Manson Jar crystallizer and highlight the conditions for growing crystals by low temperature solution method.
3. Mention the advantages of Zone melting technique and explain the experimental procedure.
4. State the essential parameters used for the selection of a NLO crystal and give the theoretical explanation of nonlinear optics.
5. Explain the principles and instrumentation of differential thermal analysis (DTA).

PART C

Answer any FOUR questions:                                                    4 x 12.5 = 50 marks

1. Discuss the (1) Conductivity (2) Visual observation and (3) Dilatometer methods of induction period measurement.
2. Give the structure of silica gel and explain the gelling mechanism (4.5) With a neat sketch describe any three experimental methods of gel technique.(8)
3. Outline the classification of various kinds of vapour growth processes. Discuss the physical vapour and chemical vapour deposition methods.
4. Explain the fundamentals of Fourier Transform spectroscopy and discuss the experimental procedure for recording the FT-IR spectrum of a sample with the help of the schematic diagram of a FT-IR spectrometer.
5. What is meant by hardness? How is it correlated to other physical properties?                           (3.5). Give the theory and the experimental steps adopted
   for measuring the Vickers hardness number and work hardening coefficient. (9)

 

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