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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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – PHYSICS

THIRD SEMESTER – NOVEMBER 2010

    PH 3951  – CRYSTAL PHYSICS

 

 

 

Date : 09-11-10                 Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

PART A

Answer ALL questions:                                                                                             10 x 2 = 20

1. What is meant by “critical nucleus”?
2. How is primary nucleation different from secondary?
3. With reference to phase transitions, list the different methods of crystal growth.
4. Discuss the experimental procedure for controlling nucleation in a gel medium.
5. Draw the sketch of Verneuil growth apparatus.
6. Outline the principle of hydrothermal growth of crystals.
7. Distinguish between FT-IR and FT-Raman techniques.
8. List few applications of vibrational spectroscopy
9. Distinguish between DTA and DSC techniques.
10. Mention the steps involved in the Rockwell hardness testing.

PART B

Answer any FOUR questions:                                                                                   4 x 7.5 = 30

11. What are the advantages of low temperature solution growth technique? Discuss the Mason jar crystallizer setup used in slow evaporation technique.
12. What are the advantages and limitations of gel growth technique? Discuss the chemical reaction method of gel growth.
13. Compare the physical vapor deposition and chemical vapor deposition methods.
14. What do you understand by nonlinear optics? Give a theoretical explanation of nonlinear optics.
15. Explain the role of dielectric measurement in characterizing the electrical response of solids.

PART C

Answer any FOUR questions:                                                                                   4 x 12.5 = 50

16. With neat sketches explain (i) conductivity (ii) dilatometer and (iii) visual observation methods of induction period measurement.
17. Describe the experimental conditions for growing crystals by low temperature solution growth technique and explain the key parameters for optimizing the growth conditions.
18. Discuss the experimental procedure for growing crystals by Bridgman method. Also discuss the role of crucible.
19. Explain the fundamentals of UV-Vis spectroscopy and discuss the experimental procedure for recording the UV-Vis spectrum of a sample with the help of a schematic diagram.
20. What do you understand by hardness? Correlate the same with other physical properties. Explain the necessary theory, and the experimental steps adopted for measuring Vickers

hardness number and work hardening coefficient.

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – PHYSICS

SECOND SEMESTER – APRIL 2012

PH 2953 – ASTROPHYSICS

 

 

Date : 24-04-2012             Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

 

PART – A

Answer ALL questions:                                                                                                       (10×2=20)

1. What are the coordinates of the Altazimuth system and state its demerits?
2. Find the distance in a.u of a-canis majoris which has p = 0.²375 and m = -1.44.
3. Show F⁺_n = pB_n in an axissymmetric radiation from one hemisphere of a black body.
4. What is the significance of HR diagram?
5. How are binary stars classified?
6. State the causes of opacity in the stellar interior
7. Express Eddington’s mass-luminosity law. What is its defect?
8. What is meant by ZAMS?
9. What is a protostar?
10. Oultine the study of helioseismology.

 

PART – B

Answer any FOUR questions:                                                                                             (4×7.5 =30)

11. Describe the local equatorial system of coordinates for a star. Give the merits of the system.
12. Explain the method of determining the distance of stellar objects by cluster parallax method. Calculate the distance of Sirius B with magnitudes m = +8.6 and M = +11.4
13. Explain the following i) Russel-Vogt theorem ii) Modified Kramer’s law of opacity.
14. Derive all the basic equations of stellar structure
15. Apply the Virial theorem to an isothermal gas sphere and hence deduce the condition for Schoenberg – Chandrasekar limit.

 

PART – C

Answer any FOUR questions:                                                                                             (4×12.5 =50)

16 a. How is the observed magnitude of a star corrected for atmospheric extinction and color?  (8)

4. Show how Saha’s equation leads to the determination of T_ion for stars in thermodynamic equilibrium (4.5)

17 a.Apply Planck’s law of radiation to obtain an expression for the relative spectro-photometric gradient (Df) of two stars at temperatures T₁ and T₂ respectively               (7)

5. Discuss the relationships between stellar parameters for main sequence stars. (5.5)
6. Obtain expressions for the gravitational time scale both for convective and radiative equilibrium in the pre-main sequence contraction of stars. Draw the HR diagram and discuss the evolution of stars near the main sequence in star clusters.

19 a. Explain the neutrino problem.    (4)

8. Discuss the theories of nucleosynthesis to account for the abundance of elements in the Universe. (8.5)
9. Write notes on any TWO of the following.
10. i) Methods for determining the stellar radii ii) Jean’s criterion for star formation

iii) Post main sequence evolution of stars

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – PHYSICS

THIRD SEMESTER – NOVEMBER 2012

PH 3951 – CRYSTAL PHYSICS

 

 

Date : 08/11/2012            Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

PART – A

Answer ALL questions:                                                                                                                  (10×2=20)

1. List a few artificial methods of inducing nucleation.
2. Discuss the role of impurities in modifying the nucleation process.
3. Explain the mechanism of gelling.
4. Draw the apparatus for complex and de-complex method.
5. State the condition for growing crystals via hydrothermal approach.
6. Give examples for crystals grown by PVD.
7. Name a few modern versions of FT-RAMAN spectrometer.
8. Draw the experimental set-up for Kurtz-Perry SHG test.
9. Explain the procedure to determine the work hardening coefficient.
10. Mention the various kinds of polarization observed in a dielectric material.

 

PART – B

Answer any FOUR questions:                                                                                               (4×7.5=30)

11. With block diagram, discuss the functioning of a Differential Scanning Calorimeter (DSC).
12. Outline the growth of crystals by Bridgman method.
13. With suitable diagrams, explain the experimental procedure to grow crystals by chemical reaction methods employing the gel medium.
14. Discuss the procedure to determine the induction period by conductivity method.
15. With the block diagram explain the instrumentation and working of a FT-IR spectrometer.

 

PART – C

Answer any FOUR questions:                                                                                               (4×12.5=50)

16. Discuss the methodology to determine the various nucleation parameters with relevant theory and graphs.
17. Distinguish between the slow cooling and slow evaporation methods of growing crystals. With neat diagram explain the procedure for growing single crystals by low temperature solution growth along with various conditions to be optimized.                  (3.5+9)
18. List the advantages of growing crystals by melt method. Discuss the working principle involving the growth of crystal by Czochralski pulling technique. (3.5+9)
19. Explain the concept of photoconductivity. With the help of the circuit diagram discuss the procedure to measure the photoconductivity of a sample. (5+7.5)
20. Discuss the various types of hardness measurements.

 

 

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