M.Sc. (Semester III) (CBCS) Examination Mar/Apr-2018
Physics (Materials Science)
ATOMIC, MOLECULAR NUCLEAR PHYSICS
Time: 2½ Hours
Max. Marks: 70
Instructions: Q.1 and Q.2 are compulsory. All questions carry equal marks. Figures to the right indicate full marks. Use of non programmable calculator is allowed.
Q.1
Objectives questions:-

Select the correct alternatives:
06
In the nuclear shell model the spin parity of 15 is given by
1−−2
3−−2
1+2
3+2
A nucleus with mass number 204 decay by α-emission. The Q-value of the reaction is 5.26MeV. The kinetic energy of the α-particle is
5.26MeV
5.26 ×200204
2.63MeV
5.26 ×4204
The magic number in nuclear physics arises mainly due to
Dipole-dipole interactions
Short character of nuclear force
Spin orbit interaction
Coulomb interaction
Pauli's Exclusion principle state that two electrons in same orbital's have
Same spins
Different spins
Opposite spins
Vertical spins
The Lande g factor for single state is
0
2
1
3
type of molecules have all moment of inertia IA≠IB≠IC
Linear molecules
Symmetric tops
Spherical top
Asymmetric tops

Fill in the blanks:
04
Asymmetric tops types of molecules have all moment of inertia
The electric quadrupole moment is negative; shape of the nuclei is
The fine structure splitting of 3s, 3p, 2s and 2p level of hydrogen atom, the number of allowed transition between them
The Scattering amplitude of n-p interaction is
Page 2 of 2
SLR-UN-480

State true and false
04
Atomic energy levels are characterized by a quantum number n called the principal quantum number (True/False)
HCl and CO shows rotational spectra. (True/False)
If Q value of nuclear reaction is positive the reaction is endothermic. (True/False)
The selection rule for a rotational transition is, Δ J=± 1 (True/False)
Q.2

Write short notes:-
Explain electric quadrapole moment for an ellipsoidal charge distribution.
05
Write short note on superconductivity model?
05
State impotents of Lande of factor? Calculate it for 2D5/2 term.
04
Q.3

Explain various predications of the liquid drop model. Give a brief description of semiempirical mass formula.
08

Write down the predictions of the Shell Model. Give the achievements and failures of shell model?
06
Q.4

Derive an expression for differential cross-section in laboratory system for p-p scattering at low energies.
08

What are similarities between n-n and p-p forces?
06
Q.5

Describe the compound nucleus theory of nuclear reactions. Give the experimental evidences in support of this theory
08

What are nuclear reactions? Discuss various conservation laws in nuclear reactions with illustrative examples.
06
Q.6

Obtain the expression of Lande splitting factor for LS and JJ coupling.
08

Distinguish between the energy levels of a rigid and a non rigid rotor.
06
Q.7

Explain diatomic molecule as a rigid rotator.
08

Obtain the expression of for diatomic molecule as a rigid rotator.
06