1. What is the origin of magnetic moment in a neutral H-atom? Derive an expression for the orbital magnetic moment of H-atom. Name the unit for measurement of magnetic moment of atoms. What is the value of one unit.

(Amity University, May 2005)

2. What is the difference between the Paschen Back effect and Stark effect?

(Amity University, May 2005)

3. Explain the terms ‘optical pumping’ and ‘population inversion’.

(Amity University, May 2005)

4. State and explain Bragg’s law for X-ray diffraction.

(Amity University, May 2005)

5. Write short notes on

(i) Normal Zeeman Effect

(ii)Zeeman Effect

(iii)Anomalous Zeeman Effect

(iv)Bohr Magneton.

*(Amity University, May 2006)*

6. What are X-rays and how are they emitted? Differentiate between characteristic and continuous X-rays. Draw energy level diagram to illustrate the emission of X-ray spectral time.

*(Amity University, May 2006)*

7. Differentiate between normal nad anomalous Zeeman effect. Obtain expression for Zeeman splitting of lines in a normal Zeeman pattern and draw the energy level diagram to show corresponding transitions. Write selection rules for such transitions.

*(Amity University, May 2006)*

8. State and give the physical significance of various quantum numbers associated with electron in an atom.

9.What is vector model of atom? State various quantum numbers and their signifcance associated with this model.

10. Explain Russel-Sander (L-S) and *j-j *couplings of orbital and spin angular momenta. How are the term symbols (atomic states) written making use of L-S coupling?

11. What is Zeeman effect? Use vector model (quantum theory) to obtain expression for norm Zeeman shift.

12.What do you mean by space quantization.

13. What is anomalous Zeeman effect? Explain this effect taking example of splitting of sodium D lines.

14. What is Paschen Back effect, Obtain the splitting of ^{2}p and ^{2}S levels and indicate the allowed transitions in a strong magnetic field.

15. State and explain Moseley’s law and explain one of its important applications.

16. Explain the emission of continuous and characteristic Xvrays. Mention the applications of Moseley’s law.

17. Derive Bragg’s law for X-rays diffraction in crystals.

18. Explain

(i)Stimulated absorption,

(ii)Spontaneous emission and

(iii)Stimulated emission of radiation.

19. What are Einstein’s coefficients *A *and B? Obtain an expression for energy density of radiation under equilibrium condition in terms of Einstein’s coefficient.

20. Explain the significance of Einstein’s relations and Einstein’s coefficients A and B. How did Einstein’s prediction of stimulated emission lead to invention of laser.

21. Explain population inversion. What is the role of a metastable state in LASER absorption?

22. Explain

(i)Active system

(ii)Pumping mechanism

(iii)Resonant cavity for a working LASER.

23. Explain the principle of a laser. State important characteristics of laser.

24. What do you mean by coherence? Explain spatial and temporal coherence.

25. Explain the working of a solid state ruby laser with a neat energy level diagram.

26. Describe the construction and working of He-Ne laser with energy level diagram.

27. Differentiate between a three level laser and a four level laser.

28. Why population invention is essential for laser action? Explain the production of continuous level.

29. What is metastable state? How it help in LASER production? With neat figures, describe the construction and working of He-Ne laser. Mention its uses.

30. Why is it superior to RUBY LASER.

31. Mention the important applications of LASER in the medical and engineering field.

32. Describe/Explain

(i)Population inversion

(ii)Characteristics of laser beam

(iii)Interaction of radiation with matter.

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