M. Sc DEGREE EXAMINATION, FBERUARY 2018.
Fourth semester
Physics
Paper III: ATOMIC AND MOLECULAR PHYSICS
(Non CBCS Old Regulation)
2 20743
Time 3 Hours Max. Marks 100
PART — A
(Short Answer Type)
Answer any FIVE of the following. 8 40 Marks)
1. Explain the principle of atomic absorption spectroscopy.
2. Explain determination of lead in petrol by using flame emission spectroscopy.
3. Discuss the Born-oppenheimer approximation in molecular spectra.
4. Discuss the effect of isotopic substitution on rotation spectra of CO.
5. State and explain Beer- Lambert's law.
6. Explain the evaluation of molar absorptivity of isoprene.
7. Discuss the theory of IR spectroscopy.
8. Discuss the advantages of Raman spectroscopy over IR.
PART — B
(Essay Answer Type)
Answer ALL questions. 15 60 Marks)
9. Discuss the differences between atomic absorption and flame emission
spectroscopy and explain the working of flame emission spectroscopy.
Or
Explain the excitation and ionization potentials and discuss the principle and
working of constant deviation spectrometer.

10. Give the different types of molecular spectra and show that a diatomic
molecule as a rigid rotator.
Or
State and explain Franck Condon principle and write a note on dissociation
energies and pre-dissociation.
11. Discuss in detail the principle and instrumentation of non-recording double
spectrophotometer with a neat circuit diagram.
Or
Explain the basic concepts of visible spectroscopy and explain the
identification of structure of simple organic and inorganic compounds.
12. Explain the principle of IR double beam spectrometer and discuss the
analysis of IR spectra of Thymidine.
Or
Describe in detail the principle and working of Laser Raman spectrometer.
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