Aligarh Muslim University (AMU) 2011 B.Sc Physics Atomic, Molecular, Laser and CondMatter - Question Paper
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2010-2011 B.Sc. (HONS.) (PART - m) EXAMINATIONS (PHYSICS)
ATOMIC, MOLECULAR, LASER AND COND. MATTER PHYSICS
(PH-315)
Maximum Marks : 40 Duration : Three Hours
Note: (i) Answer all questions.
(ii) Use of Calculator is allowed.
1 .(a) Describe the fine structure of hydrogen atom and explain the Lamb shift observed in [4] this spectrum.
(b) What is the effect of Paulis exclusion principle on the term system? Obtain the [3] levels of d2 configuration using Briet scheme of magnetic quantum numbers.
OR
(b') Illustrate the origin of sodium Di and D2 lines and explain their behaviour in the [3] presence of magnetic field.
2.(a) Describe Raman scattering on the basis of classical theory. Explain pure rotational [5] Raman spectrum of diatomic molecule.
(b) Applying Linear Combination of Atomic Orbital (LCAO) approximation, describe [2] the formation of bonding and anti-bo Jiding of hydrogen.
OR
2'.(a) Describe the rotational spectrum of non-rigid molecule and explain the selection [4] rules associated with it. Compare the observed spectrum with the spectrum of a rigid rotator.
(b) "Describe the intensity of vibrational-electronic spectra on the basis of Frank-Condon [3] principle. ; \
3.<ji) Explain the terms: (i) population inversion, (ii) Optical pumping (iii) spontaneous [3] and stimulated emission.
(b ith suitable diagram, explain the construction and working principle of N2 laser. [3] What is super-radiance?
4.(a) Describe different lattice types in three dimension. [3]
(b) Find the expression for Madelung energy of an ionic crystal. [2]
(c) Aluminium has an fee structure. Its density is 3 x 103 kg/m3. Calculate the unit cell [2] dimension and the atomic diameter. The atomic weight of aluminium is 27.0.
5.(a) Discuss Laues interpretation of x-ray diffraction by crystals. [3]
OR
Derive the dispersion relation for the vibration of dimensional monatomic lattice. [3]
(b) . Show that the unit cell volume in reciprocal lattice is inversely proportional to that in [2]
the direct lattice.
(c) Why is the neutron diffraction used to study the structure of magnetic materials? _ [1]
-2- | |||||||||||||||
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6\(a) |
Derive the expression for dc electrical resistivity based on classical model. What is |
[3] |
Mathiessens rule? | ||
(b) |
Describe the origin of energy gap in a crystal. |
[2] |
(c) |
What is Meissner effect? Show that the Meissner effect is a necessary condition for a |
[2] |
material to be superconductor. |
Attachment: |
Earning: Approval pending. |