セMN i@ ISeries OSR I 55/3 Code No. MアエFョセ@ <its セi@ q;) "3m:->'jffi!Chl セ@ セM@ Candidates must write the Code on the title page of the answer-book. セ@ • \lfT:q Cf>\ セ@ • m-i:f?f -q セ@ セi@ セ@ • • • • • • • • \lfT:q Cf>\ セ@ セcヲゥャサ[エG`B@ セ@ セ@ m-i:f?f -ij セ@ m2r セ@ セ@ セ@ 3ffi セ@ セ@ セ@ m m-i:f?f -ij aom セ@ 15 セ@ セ@ -· 1 em セ@ セMァヲゥQエ@ セ@ セM@ 1R 1 セ」ョヲsゥアF@ I @セ m-i:f?f em セ@ セ@ セ@ 15 セ@ セ@ セ@ W:rr lT<fl セ@ 1 m-i:f?f セ@ fc«RuT セ@ -ij 10.15 セ@ セ@ \ifTQ!IT I 10.15 セ@ セ@ 10.30 セ@ セ@ セ@ セ@ m-i:f?f ・ュセ@ 3fu セ@ 31cffu セ@ セ@ セ@ セMウヲゥQ@ 'R セ@ セ@ セ@ セ@ 1 Please check that this questio n paper contai ns 15 printe d pages. Code numbe r given on the right hand side of the questi on paper should be writte n on the title page of the answe r-book by the candid ate. Please check that this questio n paper contai ns 30 questio ns. Pleas e write down the Serial Numb er of the quest ion befor e attem pting it. 15 minute s time has been allotte d to read this questi on paper. The questi on paper will be distrib uted at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the studen ts will read the questi on paper only and will not write any answe r on the answe r-book during this period. cqi ktcti セi@ '"I ( セ\[エャヲN_。・ゥI@ PHY SIC S (The ory) セSヲ」ョZWP@ Time allowed : 3 hours 55/3 Maxim um Marks : 70 1 P.T.O. www.examrace.com セキNイA@ (i) (ii) I セ@ # jK7 80 JTR-TT;f 'f!C(; 3fcn r!fiT セ@ (iii) ( v) >TR- r;;r ;f 81:m w.r # セ@ セ@ w;:ff 1{ セ@ # q,c1j)&c< セ@ c/; Wrr JrRr-&§Jrif/21 JTR t 3#f JTR rft;r 3icn q;r JtFN<cn >TR 9 I w WI f¥tw4 :r!f # I rmrfrr, crT 3ien7 セ ᄋ@ セ@ w;:ff # 31Jrortfi.cn WlR セ@ 3hr rflFI Jien7 セGヲゥエC@ 1{, ?f/;r 3ien7 FcP:rr TTlTT セ@ 1 JTR JTR tt Cf>RT # I セ@ WI: TfTJ:"qZFf ., 8 セ@ ;rtf 9 1 rr2lTf2r セ@ 31Jct:t21Cf? セ@ rr7 3174' &!J'JuJc/i)JI c/; '3T!ffl ctt セ@ mruf t r!fiT ;rqfrr CR セ@ (vii) (fCf) ((1 3icn r!fiT 9, JTR 19 8 27 1{ セ@ JTR rfhr 3fcn r!fiT # I Jien7 CfTC? w;:ff # 8 セ@ rfR H8 9I JTR Wrr 9 tl18 1{ セ@ 9 3hr JTR 28 8 80 # セ@ (ivJ (vi) JTR t I Wrr 1 317<#2/cn セ@ t I 3174' RA!&fisld セ@ R21di(:;)J" c/; '11R1 r!fiT セ@ CR セ@ t: 8 c = 3 x 10 m/s 34 h = 6·63 x 10- Js = 1·6 X 10-19 C 1 7 1-lo = 41t x 10- T mA- e 1 - 4m; 0 ffie = 9 X 109 N m 2 c-2 = 9·1 X 10-31 kg Gen eral Inst ruct ions : (i) (ii) (iii) (iv) 5513 All ques tions are compulsory. 8 are very shor t answ er There are 80 questions in total. Questions No. 1 to type questions and carry one mar k each. tions 19 to 27 carry Questions No. 9 to 18 carry two mar ks each, ques mar ks each. thre e mar ks each and questions 28 to 80 carry five htage is valu e base d One of the questions carr ying three mar ks weig question. 2 www.examrace.com (v) There is no overall choice. However, an interna l choice has been provide d in one question of two marks, one question of three marks and all three questions of five marks each weightage. You have to attemp t only one of the choices in such questions. Use of calculators is not permitted. However, you may use log tables if necessary. (vi) (vii) You may use the following values of physica l constants wherever necessary: c = 3 x 108 m/s h = 6·63 x lo-34 Js e = 1·6 X 10-19 C !lo = 4n x 10_7 .T mA-1 1 - -= 9 4nE 0 X 109 N m 2 c-2 me= 9·1 X 10-3 1 kg m -ij セ@ 1. ./ セ@ -ij セ@ セ@ 'tOO セ@ セ@ セ@ セ@ セ@ :mcJ セ@ HセI@ セ@ セ@ セャHア@ OR -ij sャアセ\Q@ セi@ OR PQ セ@ 'tOO -ij セ@ セ@ セ@ セ@ セ@ I mWl 1 ーMイセq@ 0 A conduc ting loop is held below a current carryin g wire PQ as shown. Predict the directio n of the induced current in the loop when the current in the wire is constan tly increas ing. ーMセイq@ 55/3 0 3 P.T.O. www.examrace.com 2. !f[1F ュセ@ -q セ@ セM@ mgm f.rom fcMq v0 cnr セ@ A セ@ B セ@ セ@ セG@ .-r.n セ@ セ@ 1 セ@ fc!Rf;{ol <tl • mgm -q -a セュァ@ セ@ v セ@ セ@ wヲエᄋセSオZ」ュ_@ 1 セb@ ' W - -0 / e ' ./' '' ' '' '' ' '' '' ' セa@ セ@ fc!Rf;(UI セᄋHカI@ セ@ The graph shows variation of stopping potential V0 versus frequency of incident radiation v for two photosensitive metals A and B. Which of the two metals has higher threshold frequency and why? i Metal B Metal A Stopping potential (Vo) Frequency of incident radiation (v) セ@ - -e 55/3 4 .. www.examrace.com [ セ@ 3. セ@ Gl セrゥ・ャA@ セ@ セh@ 'qleJCf>l セ@ セ@ セ@ cfiT fictif<'l"il B\Zヲゥtセ@ セュオ」ヲゥャ@ 1 Using the concept of force between two .infinitely long parallel current carrying conductors, define one ampere of current. 1·25 ,3iqcHt"iiCfi セ@ 4. セMゥェ@ セ@ Qュセ@ セRヲ@ セ@ I -ij ?Cfiroll セ@ -aR セ@ セ@ Hヲャセ@ "3"1lllctctel セ@ セMゥェ@ cnl1·33 LSゥア」エヲセcィ@ Ol!CI$R セ@ Sャセ@ セ@ セ@ I 1 A biconcave lens made of a transparent material of refractive index 1·25 is immersed in water of refractive index 1·33. Will the lens behave as a converging or a diverging lens ? Give reason. セM。ヲ[イ@ 5. @セ セM@ cn1 セ@ エャセ@ ? Why do the electric field lines never cross each other ? 1 6. 1 To which part of the electromagnetic spectrum does a wave of frequency 5 x 1011 Hz belong? 7. 1 Why is it found experimentally difficult to detect neutrinos in nuclear 13-decay? セᄋ@ d.c. cilC'"tdl cヲゥイッャセ@ cfiT セ@ -ij a.c. cilC'"tdl セ@ セ@ cn1 ュセヲエcゥ、ャ@ Cf<i1 セ@ セ@ セ@ ? C!) I 1 Why is the use of a.c. voltage preferred over d.c. voltage ? Give two reasons. セ@ 9. セ@ セ@ セQNMッ\@ セ@ m セ@ セュイ・@ セ@ mu セ@ CfiRUT '1G Ol!"NCh セ@ cfiT Sゥエセ」@ セ@ セ@ cn1 セヲゥZ_ャrQ。@ Sゥャ」エセAcヲ、@ セ@ セ@ セ@ セ@ セ@ l:R セ@ セャイ@ fcFm: セ@ セ@ セ@ Bcヲエアセ@ セ@ セ@ CfiT 1 2 Considering the case of a parallel plate capacitor being charged, show how one is required to generalize Ampere's circuital law to include the term due to displacement current. 55/3 5 L P.T.O. r www.examrace.com セ@ 10. セ@ セ@ em:, セ@ セM」ョイZ@ Cfil セ@ 2·5 x 10-7 m 2 @セ セ@ セ@ 2·7 A mu SIC41ftFi "@ t, セ@ セ@ セjゥ」エ_[t\Q@ cfiT セ@ セ@ セ@ Cfil セ@ セi@ 28 ヲ・ョセ@ 3 セXエ_t\ゥQ@ Cfil セ@ 9x 10 m- セ@ I Esti mat e the ave rage drif t spee d of con duc tion elec tron s in a cop per wire of cros s-se ctio nal area 2·5 x 10- 7 m 2 carr ying a curr ent of 2·7 A. Ass ume the den sity of con duc tion elec tron s to be 9 x 1028 m-3 . セ@ 11. セ@ セ@ m セZ」イ@ セH・ュヲI@ 'E' om 3'11'"(1f{Cf1 mu tr 'r' t, セ@ セ@ WlC1 セ@ TTm セ@ 1 セ@ cfiT セ@ c:ik·cjil 'V' 3fu: mu 'I' 1 セ M ュ」Zpcヲゥャセ@ (emf) 3fu: セ@ 3'11'"(1ftcn >I'Rrittr CfiT セ@ セ@ >JCfiR fuU B bセャ@ >rRr{t'QCfl 'R' セ@ セ」ョIュ[ー@ ヲ・ョセ@ 2 Cfil セM@ セ@ セ@ 2 A cell of emf 'E' and inte rnal resi stan ce 'r' is con nect ed acro ss a vari able resi stor 'R'. Plot a grap h show ing vari atio n of term inal volt age 'V' of the cell vers us the curr ent 'I'. Usi ng the plot , show how the emf of the cell and its inte rnal resi stan ce can be dete rmi ned . mftn 12. C セ@ セ@ セ@ セ@ '8ql'"(l( セ@ m セエョヲオャ@ mfurr セ@ セ@ セi@ col fcNq セ@ セエョヲャL@ セ@ V CfCf1 SGQセc@ SPQセ。@ セ@ t, "B' セ@ 3fu: セュヲオcゥ@ セBw\ヲ@ TTm i セ@ B41WIC1 セ@ I 2 A para llel plat e cap acit or of capa cita nce Cis cha rged to a pote ntia l V. It is then con nect ed to ano ther unc harg ed cap acit or hav ing the sam e capa cita nce. Fin d out the rati o of the ene rgy stor ed in the com bine d syst em to tha t stor ed init ially in the sing le capa cito r. セ@ 13. セ@ セ@ &i サセH|「ャゥ@ セ@ セ@ セ@ セ@ セ@ セ@ CfiT セ@ セ@ セ@ セ@ セi@ セ@ I セjャ」エ_HBゥ@ セ@ セ@ セ@ セ@ ¥1 セ@ Cfil セ@ セ@ セ^jcヲャr」ゥイ。@ 55/3 VQセ|ゥャB@ セ@ セX」エ_t\ゥ@ ::ttunc-qc:n セ@ セjゥ」エ_t\@ cf;1 セ@ セ@ CfiT Cfm 312f セ@ cf;1 neff cna11 セ@ セ@ ? 2 セ@ I 2 6 ... www.examrace.com セ l L Using Rutherford model of the atom, derive the expression for the total energy of the electron in hydrogen atom. What is the significance of total negative energy possessed by the electron? OR Using Bohr's postulates of the atomic model, derive the expression for radius of nth electron orbit. Hence obtain the expression for Bohr's radius. (i) セェSォャ」ィ\Zエ@ 14. セ@ セ@ Ficセr@ セ@ セ@ (ii) sャォSゥ]セ」ィ\Zエ@ セ@ @f::qq;{ セ@ I セ@ cfa セ@ セ@ if 3klchl<:t セ@ cfa &13=11 セ@ &11&41 セ@ セ@ cfit セ_@ 2 Show diagrammatically the behaviour of magnetic field lines in the presence of (i) paramagnetic and (ii) diamagnetic substances. How does one explain this distinguishing feature ? 3lfu9 cfa bセャ\Zエッ@ -qftq-2:[ 15. ,. セ@ cfit "B セ@ &11&41 セ@ p-n Bftr セ@ セ@ SヲTMセ@ Rt:>C:Chltl セゥエ@ I 2 Explain, with the help of a circuit diagram, the working of a p-n junction diode as a half-wave rectifier. 16. b * セ@ キGャヲオセ@ セ@ ("ll•ii:n'lul セabc@ セ@ セ@ セZ@ セ@ " 1·38 AB 3TitRR 3fu: "Cfl«fi セ@ 1·52 セ@ iセ@ '11{ セ@ J1¥ffi セcヲャゥッ@ セTcゥ、Bヲャ@ fen<oif cn8 セ@ I "fT fen<oif セゥヲ@ セi@ >rCnro セ@ cfa '1' Cf '2' セ@ 1:f2f 2 A '1' Mセエ@ '2'-+----1 c B 55/3 7 P.T.O. ... www.examrace.com Two mono chrom atic rays of light are incide nt norma lly on the face AB of an isosceles right- angle d prism ABC. The refrac tive indice s of the glass prism for the two rays '1' and '2' are respec tively 1·38 and 1·52. Trace the path of these rays after enteri ng throu gh the prism . A c CE rャイ\ッセ@ 17. セ@ -ij n-p-n s;iMR< Mウイアセ@ セ@ セ@ s;iMR< セ@ Cl)T Mアヲエセ@ 3lfusr セ@ iセ@ -ij セ@ -ij CfiTcf CfiUfT セ@ ? 2 Draw a circui t diagr am of n-p-n transi stor ampli fier in CE config uratio n. Unde r what condi tion does the transi stor act as an ampli fier ? セ@ 18. .. .q セ@ セ@ CfiTcf セ@ : 2 セ@ (i) ! ヲNゥアセオャ、@ Rlx:tT§eCfl (ii) Write the functions of the following in comm unicat ion system s : (i) Receiver (ii) Demo dulato r 20 em セ、ュQア[I@ 19. セFt@ セM@ 20 ・ュセ@ -6 15 em セ@ lR &T TTm @セ I セ@ fil"1fihd セ@ セ@ セ@ $ セ@ セ@ "ffil-B 40 em ?tt lR &r \ifrnT 1セ@ Tャ|Bゥ@セ セ@ セ@ sirエヲゥャセ@ cf>t セ@ mo セ@ I sirセ@ Gf.HT セ@ セ@ セ@ セ@ 3lfug セ@ I A convex lens of focal length 20 em is placed coaxially with a convex mirro r of radius of curva ture 20 em. The two are kept 15 em apart .A point object is placed 40 em in front of the convex lens. Find the positi on of the image formed by this combination. Draw the ray diagra m showi ng the image forma tion. t 55/3 3 8 .. www.examrace.com em セ\G|」エ_tBゥ@ 20. セ\G|」エ_ャᄋゥ@ セ@ セ@ セ@ 50 kV セ@ -B セ@ セM@ en) m 1lr-ffi セG@ 、サャゥセBcT@ sicヲゥセ@ セ@ cnC'"cdl セ@ セ@ セ@ セ@ セ@ セ@ セ\G|」エ_tBゥ@ セ@ セ\G|ゥヲ_t[ャ@ I セ@ セ@ セ@ cnr セ@ セG@ セ@ セ@ セ@ セ@ セ@ Q)ar t, セ@ CfiT セ@ Cf>«<T セ@ セ@ I セ@ セ@ セ@ t セ@ t ? 3 An electron microscope uses electrons accelerated by a voltage of 50 kV. Determine the de-Broglie wavelength associated with the electrons. Taking other factors, such as numerical aperture etc. to be same, how does the resolving power of an electron microscope compare with that of an optical microscope which uses yellow light ? セ@ 3l100 セ@ セ@ 31Ttm 1:R ilR1Chl, セ@ 3fu: セM@ セ@ iftq セgI@ セHQB」ョャ@ 3 Write any two distinguishing features between conductors, semiconductors and insulators on the basis of energy band diagrams. セ@ 22. セ@ セ@ セ@ セ@ セwi@ HセI@ I 3WnlT Ttᄃセ]Q@ 3lit& cnt &l"ilcti\ セ@ セ@ セ@ セ@ セ@ SQセオアッG@ セ@ セ@ セ@ セ@ fcf> セ@ 3l1<fllJ 4T§Wtd )I"Cf)'R セ@ セ@ \i"41qshlll セ@ Olll@l セ@ I Wl1 1R Ttᄃセ」ョ@ fur.:R.1 >Trn セ@ セ@ t 1 3 Write two basic modes of communication. Explain the process of amplitude modulation. Draw a schematic sketch showing how amplitude modulated signal is obtained by superposing a modulating signal over a sinusoidal carrier wave. 3 (a) lfR:< "Bg -ij \ifRfT (b) Bsヲゥイッセ@ セ@ cnT cnftR iftq セエゥィNヲ@ セ@ llltt t® CfiT セ@ セ@ t? lfR:\ セ@ セ@ <m: l:R セQTBャ、Z@ セ・ョI@ lf'al -ij >Trn セ・ョI@ Bsjtセヲ_Acャ、@ セエ_@ (c) lfR:< "Bg セ@ <m: セ@ セ@ セ@ 55/3 セ@ CfiT セ@ 9 セ@ \ifRfT t 3fu: セ_@ P.T.O. ... www.examrace.com L _ セ@ セ@ セ@ -ij セ@ 3Wffi >rfuUcq Ro Q セ@ セ@ RQ OR セ@ セi@ セ@ >TfWrcq セ@ セ@ 't.lRT 'ffirr セ@ I セ@ I セ@ col V Jl<'"cdl cfa セ@ cfa \ifRft セ@ li'G f -ij t セ@ R セ@ fuU -en: Jl<'"cdl セ@ ffi"Q: セ@ Cf)T .- -- -- -- V - - - - - -, ,w,, 'j An sw er th e following Cf)T I セ@ セ@ セ@ セL@ : (a) W hy ar e th e co nn ec tio ns be tw ee n th e re sis to rs in a m et er br id ge m ad e of th ick co pp er str ip s ? (b) W hy is it ge ne ra lly pr ef er re d to ob ta in th e ba la nc e po in t in th e mi dd le of th e m et er br id ge wi re ? (c) W hi ch m at er ia l is us ed for th e m et er br id ge wi re an d w hy ? OR A re sis ta nc e of R Q dr aw s cu rre nt fro m a po te nt io m et er as sh ow n in th e figure. Th e po te nt io m et er ha s a to ta l re sis ta nc e R0 Q. A vo lta ge V is su pp lie d to th e po ten tio me ter . De riv e an ex pr es sio n fo r th e vo lta ge ac ro ss R wh en th e sli di ng co nt ac t is in th e mi dd le of th e po te nt io m et er. .- -- -- -- V - - - - -, セ 55/3 10 ᄋ@ www.examrace.com 3 セ@ 24. ¥9 セ@ 3fu: fShlf icヲゥセ@ セicヲゥ@ Ill (1 セ@ -B 3lmfT 31CRT セ@ um cf?t ¥9 セ@ 141 .q (O!J<I;:qlf .q "Cfilft CfiT セ@ Cfil: セ@ 2ft m"Cfi«ft 2ft item ;r um 1 I 3lmfT セ@ セ@ CfiT セ@ liTffi -ftrnl セ@ M」イエセ@ セ@ セ@ セ@ セ@ セi@ 3Wffi 311Uft ;r fcf;;{ セ@ (a) セ@ (b) mm3ii$B1 il4 セ@ )ICf)R I セ@ ct?t セM@ セ@ セ@ cf& セ@ Mセ@ um cfiT ifcfc:tTMセ@ セ@ fcfi um セM@ M cnT セ@ セ@ :tllt1f):Cfi セG@ cfiT CfiT mrrcr -B ? CfiT セ@ .q ('!Qilfdl セ@ m セ_@ 3 For the past some time, Aarti had been observing some erratic body movement , unsteadin ess and lack of coordinati on in the activities of her sister Radha, who also used to complain of severe headache occasionally. Aarti suggested to her parents to get a medical check-up of Radha. The doctor thoroughl y examined Radha and diagnosed that she has a brain tumour. 25. What, according to you, are the values displayed by Aarti? (b) How can radioisoto pes help a doctor to diagnose brain tumour? (a) z セ@ cf?t セ@ セ@ Q!-fl(O!J<IH セォャ」ヲI@ セ@ !$r .q セ@ セ@ Q!-fl('!J<IH セ@ セヲオ、gゥZアュN[H・I@ セ@ (b) ヲ」イキャMセ@ (a) '\ (b) 55/3 \ (a) セ@ 'v' "B C1kl*l セュ@ セZ@ セ@ セ@ セ@ セH・ュヲI@ セ@ セ@ "tR セ@ cnT セ@ セ@ 1'fffi セ@ セ@ \ifRft t I セ@ 1 Mft"{'#t @セ Cf)T @セ セ@ lB' セ@ )ICf)R @セ セ@ -aCfiffi セ@ ? Olfi&QI セ@ I 3 A rod of length l is moved horizontal ly with a uniform velocity 'v' in a direction perpendic ular to its length through a region in which a uniform magnetic field is acting vertically downward . Derive the expression for the emf induced across the ends of the rod. How does one understan d this motional emf by invoking the Lorentz force acting on the free charge carriers of the conductor ? Explain. 11 P.T.O. www.examrace.com 26. セ@ (a) 3lTt& セ@ セ@ セ@ (b) セG@ GJQ セ@ P 1 Hヲセ@ <1Mi!Cl<i_ セ@ t fenGfT \jfT セ@ TIjャ、セウ@ セ@ セ@ 4{1Cld"i セ@ I P 2 」ゥエセ@ mI セ@ &P T( iT 10 q:;r セ@ t セ@ SQセ@ セ@ セ@ cit セ@ l:ffftcr-31a:r セM@ セ@ P 1 'tl'{ セ@ I fcnBT cfR:R P3 CfiT P 3fu: P セ@ @ セ @ セ 1 )fC f)R "{@ 'l'1m 2 fcn セ@ "tJTfuf-31a:r P 1 セ@ "4'Tftf-31a:r セ@ 60° q:;r CfiTur セ@ I P 1' P 3fu: P セ@ セ@ 2 3 セ」イ[@ I Sh ow , giv ing a su ita ble dia gr am , ho w un po lar ize d lig ht ca n be po lar ise d by ref lec tio n. TQjャVセウ@ (a) (b) t t 3 Two po lar oid s P an d P 2 are pla ce d wi th the 1 ir pa ss ax es pe rp en dic ula r to ea ch oth er. Un po lar ise d lig ht of int en sit y 1 is inc ide nt on P . A th ird po 0 lar oid P is ke pt in be tw 1 ee n P an d P 3 su ch th at its pa ss ax is 1 2 ma ke s an an gle of 60° wi th th at of p 1" De ter mi ne th e int en sit y of lig ht tra ns mi tte d thr ou gh P 1' P an d 2 P3 . セ@ 27 . セ@ セMア@ セ@ LC R ByヲオZjセ@ セ@ 'tl'{ セ@ セicB」ッ、ャ@ V 。⦅wイョセ@ セ@ -q m<rr, (ii) ByヲオZjセ@ = V0 sin cot セェsiQGヲゥ@ t cr;r セ@ I セ@ I (i) セ@ MアヲオZjセ@ -q セ@ = V0 -q セ@ ュMセ@ mu m<rr t m '4T セM@ SICIIf%d セwiエ@ ? セ@ 3 A vo lta ge V sin cot is ap pli ed to a se rie s LC R cir cu it. De riv e ex pre ssi on for the av era ge the po we r dis sip ate d ov er a cy cle. Un de r wh at co nd iti on is (i) no po we r dis sip ate d ev en tho ug h the cu rre nt flows thr ou gh the cir cu it, (ii) ma xim um po we r dis sip ate d in the cir cu it? 28 . W1 セ@ @セ :qq4))ct) (a) セBsith@ <rr セ@ (b) セ@ セ@ セ@ 3fu: セ@ m m c(;T セTQ@ -q, セ@ mft<:rT HセI@ -q CfOT;r セ@ セ@ セ@ セ@ "5liH cr;r セ@ セ@ I -q PtrAGO 3fu: セ@ q:;r 31jtfRf "ffiO セ@ SQセ@ 55 /3 セ@ c(;T cfurnr311 Cf)T セ@ I セ@ セ@ セ@ I セ@ セ@ セ@ 'tl'{ セ@ 9 : 2s セ@ 1 5 12 www.examrace.com (a) -q quf;r セ@ fWT セ@ セ@ セ@ セ@ セ@ )l'Tt(f セ@ セ@ セcヲIアo{@ 11\ 3fu: セ@ fuc«R ヲセ\IHA・ー@ セ@ セ@ セ@ セ@ セ@ セ@ >rrn M )ICf)R Ptfi:it56 セ@ セ@ セ@ セ@ \jffifT セ@ セ@ セ@ I セ@ セi@ V 2 x QPM (b) セ@ セ、ャ\oAcヲ@ )J(fi"R fenm セ@ fWT セ@ ュセ@ セMゥヲ@ ヲエャセ\oia@ M >rrn m-eR セ@ cnT セ@ セ@ セ@ I fWT T[(f[ -q セ@ 3fu: セ@ セ@ セ@ セ@ セ@ 3Gi:lt56 セ@ セ@ セ@ nm セ@ 3fu: 596 590 run セ@ cnT 3l'l::<l<R セ@ セ@ 1·5 m セ@ Q_セ@ セ@ セ@ Q 、サ I セ@ セ@ セ@ QセGui@ -q セ@ セ@ qft6flred セi@ (a) 5 (b) In Young's double slit experiment, describe briefly how bright and dark fringes are obtained on the screen kept in front of a double slit. Hence obtain the expression for the fringe width. The ratio of the intensities at minima to the maxima in the Young's double slit experiment is 9 : 25. Find the ratio of the widths of the two slits. ( ) \..\ OR 29. (a) Describe briefly how a diffraction pattern is obtained on a screen due to a single narrow slit illuminated by a monochromatic source of light. Hence obtain the conditions for the angular width of secondary maxima and secondary minima. (b) Two wavelengths of sodium light of 590 nm and 596 nm are used in turn to study the diffraction taking place at a single slit of aperture 2 x 10- 6 m. The distance between the slit and the screen is 1·5 m. Calculate the separation between the positions of first maxima of the diffraction pattern obtained in the two cases. (a) 1At4i1<01 セ@ セ@ -q M SGQセ、@ 3fu: セ@ セ@ セ@ セ@ onur セ@ • qftSfiAOI セ@ q;ur セ@ セ@ Wr セ@ セ@ セ@ -en: ;w.rcn セ@ セ@ -Rm: セi@ セckQGャ_tB@ (b) セ@ CfiT セ@ セ@ セ@ セ@ セ@ セ@ "§:Q: 041&11 セ@ )ICf)R M f<n \jffifT I セ@ SGQセH@ 6I セ@ q;uft -Ch) cnT 3'11ct!i4i:.h セ@ rctitJ セ@ セ@ セ@ セ@ 5 Sエセ@ 55/3 " 13 P.T.O . ... www.examrace.com T.R1 セッZァhj@ (a) セ\B_pヲャ」x@ Cht<fst on cll CfiT CfiT •llliiRtla セ@ R&:;1R1fula セ@ (b) セ@ セ@ セ\BᄋエィZヲャ」@ (i) セ@ セ@ I セ@ 3fu: ru;&t'fl I セッZァ」ゥI@ セ@ QcャセTィ@ "Rtlm (ii) croR セ@ : -aa)-cr セ@ セ@ セ@ セ@ efRJ ;flf セ@ 9n1:s en) セhicィャH@ セ@ セ@ ? セBQT」ク@ cfiT mu セキr[。エ@ fcf; セ@ ql<"cdl セQEH@ セPTQ`@ -q セ@ セ@ セ・ョMg@ CfiT セ@ セrcャT、Z@ mセ@ セ@ セ@ セ@ I "Cf)RUT セ@ I 5 (a) Deduce an express ion for the frequency of revolut ion of a charged particle in a magnet ic field and show that it is indepen dent of velocity or energy of the particle . (b) Draw a schema tic sketch of a cyclotron. Explain, giving the essenti al details of its constru ction, how it is used to acceler ate the charged particle s. セ@ J.-1' OR (a) Draw a labelled diagram of a moving coil galvano meter. Describ e briefly its princip le and working. (b) Answer the following : (i) Why is it necessa ry to introdu ce a cylindr ical soft iron core inside the coil of a galvano meter ? (ii) Increas ing the current sensitiv ity of a galvano meter may not necessa rily increas e its voltage sensitiv ity. Explain, giving reason. セ@ 30. セ@ セ@ セ@ セ@ セ@ セ@ セ@ セ@ 'ChT "llliiFtla セ@ セ@ セャBGヲサ。@ セャ、@ セ@ セ@ I セ@ |ゥャセ@ セ@ セ@ t セ@ セ@ tヲャhセGcィッR@ セ@ セ@ セ@ セ@ セ@ セ@ fcfi, セ@ セ@ "tR セ@ "Rtlm 'SICfm: l1ffi -ij Cf1T Chi4Cfil{) m;&l'fl セ@ 1 セ@ 1 (a) セ@ QlheliH セMャDj@ E cfiT セ@ セ@ セ@ "tR セ・ョgM@ 55/3 セ@ セ@ 5 t crra セ@ セ@ I 14 ... www.examrace.com sl o2IT s2 セュMョZ@ ュMゥェセ@ (b) セ@ 2Q (l2IT 4Q セ@ 1Cii) セ@ 3WTif セ@ セ@ m: セ@ 'er' Cf)l セ@ セ@ ? ゥャ」エセT@S qf):c:nf"l セ@ mrn I (i) セ@ \fuRt セ@ s1 セ@ セ@ セ@ セZ@ s1 セ@ セL@ m セ@ セ@ セ@ セ@ セ@ -ij セ@ セ@ -B セ@ セ@ "CffiCm cnT tn: T\Qセ。ゥ@ @セ @セ qffi セ@ -q 5 I ·' / Draw a labelled diagram of Van de Graaff generator. State its working principle to show how by introducin g a small charged sphere into a larger sphere, a large amount of charge can be transferre d to the outer sphere. State the use of this machine and also point out its limitation s. OR (a) Deduce the expression for the torque acting on a dipole of dipole moment (b) 55/3 p in the presence of a uniform electric field "Ef . Consider two hollow concentric spheres, S1 and S2, enclosing charges 2Q and 4Q respectively as shown in the figure. (i) Find out the ratio of the electric flux through them. (ii) How will the electric flux through the sphere sl change if a medium of dielectric constant 'Er' is introduced in the space inside S1 in place of air ? Deduce the necessary expression. 4Q 15 www.examrace.com
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