MSCPH-03 June - Examination 017 MSC (Previous) Physics Examination Solid State Physics R>mog AdñWm ^m {VH$s Paper - MSCPH-03 Time : 3 Hours ] [ Max. Marks :- 80 Note: The question paper is divided into three sections. A, B and C. Write answer as per the given instructions. Check your paper code and paper title before starting the paper. In case of any discrepancy English version will be final. {ZX}e : h àíz nì "A', "~' Am a "g' VrZ IÊS>m {d^m{ov h & àë oh$ IÊS> Ho$ {ZX}emZwgma àízm Ho$ CÎma Xr{OE& àýnì ewê$ H$aZo go nyd àýnì H$moS> d àýnì erf H$ Om±M bo& {H$gr ^r {dg JVVm H$s pñw{v A J«oOr ê$n ApÝV mzm Om ojm& Note: Section - A 8 = 16 (Very Short Answer Type Questions) (Compulsory) Answer all questions. As per the nature of the question delimit your answer in one word, one sentence or maximum upto 30 words. Each question carries marks. MSCPH-03 / 300 / 6 (1) (P.T.O.)
IÊS> - "A' (A{V bkw CÎma dmbo àíz) {ZX}e : g^r àízm Ho$ CÎma Xr{OE& Amn AnZo CÎma H$mo àízmzwgma EH$ eãx, EH$ dm³ m A{YH$V 30 eãxm n[agr{ V H$s{O o& àë oh$ àíz A H$m H$m h & 1) (i) What is the value of packing fraction of F.C.C. crystal? {H«$ñQ>b H$m g Hw$bZ JwUm L²>H$ {H$VZm h? (ii) Fermi Dirac probability distribution function is given by 1 f( e) = e - ef exp` j + 1 KT Find the value of this function f( e ) at temperature 4k for which the electron has energy equal to fermi energy. f $ r {S>amH$ àm{ H$Vm {dvau $bz ( e ) = 1 e - ef exp` j + 1 KT Ûmam {X m OmVm h Vmo 4k Vmn na Bg $bz H$m mz Bbo³Q >m Z Ho$ {be kmv H$amo {OgH$s D$Om $ r D$Om Ho$ ~am~a hmovr h & (iii) Suppose in a crystal, alattice plane cuts intercepts of a, b and c along the three crystallo graphic axes. Find the Miller indices of the given plane. EH$ {H«$ñQ>b EH$ OmbH$ Vb a, b VWm c Ho$ AÝV I S> VrZ {H«$ñQ>br Ajm na H$mQ>Vo h Vmo {XE JE Vb Ho$ { ba gymh$m H$ kmv H$amo& (iv) Suppose energy E of electron is solid varies with wave number K as E = a + bk + ck where a, b and c are constants. Find the effective mass of the electron. MSCPH-03 / 300 / 6 () (Contd.)
mzm {H$ R>mog o Bbo³Q >mz H$s D$Om E, Va J g» m K Ho$ gmw E = a + bk + ck H$s Vah n[ad{v V hmo ahr h Ohm± a, b Ed c AMa h Bbo³Q >mz H$m à^mdr Ðì mz kmv H$amo& (v) If polarization vector is p = 3xit + yj t - kt. Then find the polarization charge volume density. {X Y«wdUg{Xe p = 3xi t + yj t - k t Vmo Y«wdU Am VZ Amdoe KZËd kmv H$amo& (vi) A relation for Phonon wave is given by w = a 1 - cos ka where a and a are constant. Find the value of K for which group dw velocity is minimum. dk $mozmoz Va J H$m g rh$au w = a 1 - cos ka Ûmam {X m OmVm h Ohm± a VWm a AMa h Vmo K Ho$ do mz kmv H$amo {OZHo$ {be g yh dw doj dk {ZåZV hmojm& (vii) Draw the graph showing the entropy versus temperature curve for super conducting and normal state. A[VMmbH$ VWm gm mý AdñWmH$mo Xem Zo dmbo EÝQ >mnr VWm Vmn mz J«m $ H$mo ~ZmAmo& (viii) What do you mean by ferroelectric materials? o$amobbop³q >H$ nxmw go Amn ³ m g PVo hmo? Section - B 4 8 = 3 (Short Answer Type Questions) Note: Answer any four questions. Each answer should not exceed 00 words. Each question carries 08 marks. MSCPH-03 / 300 / 6 (3) (P.T.O.)
(IÊS> - ~) (bkw CÎma dmbo àíz) {ZX}e : {H$Ýhr Mma àízm Ho$ CÎma Xr{OE& Amn AnZo CÎma H$mo A{YH$V 00 eãxm n[agr{ V H$s{OE& àë oh$ àíz 08 A H$m H$m h & ) Draw and explain the diamond structure. S>m ÊS> g amzm H$mo ~ZmAmo VWm Bgo g PmAmo& 3) If primitive lattice vectors of the FCC lattice are a a c1 = ( i t + t j ), c = ( t j + k t a ) and c3 = ( i + k ) t t then find the reciprocal lattice vectors for this lattice. a a i j c j k {X OmbH$ Ho$ A^mÁ OmbH${Zn Vm±H$ c1 = ( t + t), = ( t + t) a i Ed c3 = ( t + k t ) h Vmo Bg OmbH$ Ho$ ì wëh«$ OmbH$ g{xe kmv H$amo& 4) Explain the concept of population Inversion and stimulated mission. OZg» m ì wëh«$ U Ed g ào[av CËgO Z H$s A{ YmaUmAm H$s ì m» m H$amo& 5) Explain the F centers in crystals. {H«$ñQ>b F Ho$ÝÐm H$mo g PmAmo& 6) Write a short note on Drude Lorentz theory of electrical conductivity of metals. YmVwAm H$s {dúwv MmbH$Vm Ho$ S >çws> bm aoýo {gõmýv na g {já {Q>ßnUr {bimo& 7) Describe the Einstein model of specific heat of solid. R>mogm Ho$ {d{eï> Cî m Ho$ AmBÝgQ>rZ ms>b H$m du Z H$amo& MSCPH-03 / 300 / 6 (4) (Contd.)
8) Explain the electronic polarisability of substances. nxmwm] H$s Bbo³Q >m{zh$ Y«wdUVm H$s ì m» m H$amo& 9) Explain the thermal conductivity and specific heat of super conductors. A{V MmbH$m H$s Cî r MmbH$Vm VWm {d{eï> Cî m H$mo g PmAmo& Section - C 16 = 3 (Long Answer Type Questions) Note: Answer any two questions. You have to delimit your each answer maximum up to 500 words. Each question carries 16 marks. (IÊS> - g) (XrK CÎma dmbo àíz) {ZX}e : {H$Ýht Xmo àízm Ho$ CÎma Xr{OE& Amn AnZo CÎma H$mo A{YH$V 500 eãxm n[agr{ V H$s{OE& àë oh$ àíz 16 A H$m H$m h & 10) (i) Discuss Laue equations and Bragg's law. (ii) Explain the terom phonon. Write all characteristics of phonons. (i) bdo g rh$aumo d ~«oj {Z H$s {ddomzm H$a & (ii) $mozm±z nx H$mo g PmAmo& $mozm Z Ho$ g ñv A{^bmj{UH$ JwU {b{ie& 11) What is periodic potential? State and Derive the Block theorem. AmdVu {d^d ³ m h? ãbm H$ à o H$m H$WZ H$amo Ed Bgo ì wënþ H$s{OE& 1) Explain the quantum theory of paramagnetism and on the basis of this theory plot the graph between magnetic moment and applid field. AZwMwå~H$Ëd Ho$ ¹$m Q> {gõmýv H$mo g PmAmo VWm Bg {gõmýv Ho$ AmYma na Mwå~H$s AmKy U VWm Amamo{nV joì Ho$ Ü J«m $ ~ZmAmo& MSCPH-03 / 300 / 6 (5) (P.T.O.)
13) (i) What is Josephson Effect? Distinguish between DC and AC Josephson effects. (ii) Explain the spontaneous polarisation an dielectric hysteresis in ferroelectrics. (i) Omog $gz n«^md ³ m h? DC Omog $gz Ed AC Omog $gz à^mdm {^ÞVm g PmBE& (ii) o$amobbop³q >³g o ñdv Y«wdU VWm namd ÚwV e {Wë Vm H$s ì m» m H$s{OE& MSCPH-03 / 300 / 6 (6)