Download SGBAU (Sant Gadge Baba Amravati university) BSc 2019 Summer (Bachelor of Science) 6th Sem Physics Statistical Mechanics n Solid State Physics Previous Question Paper
B.Sc. (Part?lll) Semester-VI Examination
6S-PHYSICS
(Statistical Mechanics and Solid State Physics)
Time : Three Hours] [Maximum Marks : 80
1.
(A)
(B)
(C)
Note :? Attempt all questions.
Fill in the blanks : ? , 2
(1) The phase space of N particles have dimensions.
(ii) Quantum statistics is applicable to identical and particles.
(xii) Schottky defects are defects.
(iv) Superconductors are perfectly
IQ
Choose correct alternative of the following :
(i) Pauli's exclusion principle is applicable to :
(a) M-B statistics
(b) B-E statistics
(c) F-D statistics
(d) None of these
(ii) Structure of NaCl crystal is z
(a) BCC
(b) FCC
(c) Simple cubic
(d) Hexagonal
(iii) For diamagnetic materials, magnetic susceptibility is :
(a) small and negative
(b) small and positive
(c) large and negative
(d) large and positive
(iv) Nanometer is equal to :
(a) 10?3m
(b) 10*?m
(c) 107m
(d) 109m
Answer the following in one sentence : 4
(i) What are Bosons 3?
(1i) What is point defect ?
(Iii) What is Curie temperature ?
(iv) On what factors properties of nanomaterial depend ?
YBC~>15331 l (Contd.)
EITHER
2. (A) Write cxpression for thi-mmiynamic probability in M?B distribution and ?nd expression for
M-B distribution law. _ 6
(B) By using M-B distributmi Isw of molecular speed show that roo: mean square spccd ui'gns
Iii
molecule is given by \ w V A 4
m
(C) Find thc Ihcnnodmtmii?: pml?ahility for four distinguishable particles for the microstate (2. 2).
2
0R
3. (1?) Slate and explain principle (?1? priori probability. 4
. . . , 5LT
(Q) Show that most probable xrloclly 01 gas molecule IS Vp = ??7?: . 4
(R) Explain the [011113 :
(i) Themmdymmic probuhihty
(ii) Statistical weight. 4
EITHER
4. (A) What arc the main pmtulemzs 01' Fcrmi-Dirac statistics ?? 4
(B) Using anc-liinstcin dist rihution law. deduce an expression for Plam-k?s law of energy distribution
in black body radiation. 7
(C) What is Fermi energy 1? 1
0R
5. (P) Explain the concept ot?distiiiguishable and indistinguishable particles. 3
(Q) Obtain an expression for Fcnni-Diruc distribution law by assuming thermodynamic probability.
q
(R) What is Fermi function ?7 How it behaves at absolute 7ero ? 4
EITHER
6. (A) De?ne unit cell ufcryslul. 1: (plain primitch and non-primitive Lnit cell. 4
(B) Derive Bragg's law for dit?t?iaction OfX-rays. 4
(C) What is linc defect in :ryanl 1' Explain the screw dislocation in crystal with neat diagram.
4
OR
7. (P) Give the names or < cx on c: ystal systems and state the parameters oftheir unit cells. 6
(Q) What are Miller indices 1? I ind Miller indices of the plane having intercepts (21, 2b. c/2).
4
(R) What is reciprocal lattice 2? 2
EITHER
8. (A) Obtain an expression for electrical conductivity in terms of me an free path ofelcctrons.
4
(B) Discuss formation 01' i nsulator, semiconductor and conductor on the basis of band theory of
solid. 6
(C) What are conduction ?:lccuuns 7 2
YBC 715331 2 ('Contd.)
OR
9. (P) Ex'plain the motion of electron in metals and hence derive an expression for dri? velocity of
electron. 5
(0) Explain qualitatively conduction band, valence band and energy gap in solids. 4
(R) Explain nearly free electron model. 3
EITHER
10. (A) State properties of paramagnetic materials. 4
(B) Explain fcrromagnetism on the basis of domain theory. 4
(C ) What is magnetic dipole moment ? Obtain an expression for orbital magnetic dipole moment.
4
OR
I 1. (P) Give Langevin's theory of paramagnetism; hence prove that the susceptibility ofparamagnetic
material is inversely proportional to absolute temperature. 8
(Q) State properties ofdiamagnetic material. 4
EITHER
12. (A) Give brief idea of BCS theory of superconductivity. 6
(B) Explain type-I and type-II superconductor. 4
(C) De?ne : 2
(i) Critical temperature
(ii) Critical magnetic ?eld.
OR
13. (P) Explain imponancc of surface to volume ratio and quantum size effect in nanomatcrials. C
v
(Q) State any four applications of nanomaterials.
lJ-D
(R) What are nanomaterials ?
YBC 15331 3 525
This post was last modified on 10 February 2020