Unit - 18 Atom and Nucleus

Transcription

1 Ui - 8 Aom ad Nucleus 85

2 SUMMARY The disace of he closes approach of a - paricle is give by Ze γo= 4π E E where E k = o. K. The Impac parameer is give by m 9 Z = Aomic umber b = 4π.E o θ Ze Co 3 No - of Scaerig of - paricle reaered a agle is give by N = N o s m si 4 θ/ Ζe m where, No = umber of icide - paricles = o. of Aoms per ui Volume i he foil s = hickess of foil v = speed of - paricle,m = mass of paricle z = Aomic umber of (he eleme of foil) e = charge of elecro. 4 Agular momeum of elecro i Bohr orbi mvr h, whre is a ieger 5 r = radius of h bohr orbi = h o Ze m Z r 6 Eergy of elecro i h orbi is 4 me z z E 3. 6 ev 8h o E Z 7. differe speral Series Formula for ad heir gegiols (i) Lyma series, R where,,3... (ulra viole regio.) 86

3 ii) Balmer series,, R where, 3, 4,... (Visible regio.) (iii) Pasche series,, R where, 4,5 3,... (Ifrared regio.) Brake series, R where, 5, 6 4,... (Ifrared regio.) Pfud series, R where, 6, 7 5,... (Ifrared regio.) 8 For, hydroge aom eergy of elecro i h orbi 9 E 3.6 ev For hydroge like aom A Z X or Z X A 3.6 E =- z ev Z = Aomic umber = Number of Proos A = mass umber = Number of eucleos A - Z = N = Number of euros (i) For Isoope uclei Z equal ad A uequal e.g. 6 c 6 c 3 6 c4 (ii) For, Isooe uclei Z uequal, A uqual A-Z = N = equal No - of euros are equal e.g. kr ,37 Rb (iii) For, Isobar uclei z uequal, A equal (A-Z) are uequal e-g 5 B, 6 C 87

4 (iv) For Isomers ucler Z equal, A equal Bu heir radio acive properies are differe e.g. 80 Br pair 35 0 Radius of ucleus R = Ro 3 Where R o = Cosa =. fm o. fm A = mass umber Mass defec m ( zm pnm) M B.E E ( m)c Zmp Nm) M c b 3 Ui of eergy i uclear Physics or aomic Physics is ev 9 ev.60 J 4 ui of mass i uclear physics or aomic Physics is amu or u 7 amu u.670 Kg 6 u 93.48MeV ev 5 B.E Per ucleo is b E Eb A 6 - Paricle = Nucleus of Helium aom 4 Symbol of - Paricle He - Paricle = elecro emied From ucleus i eo γ - radiaio = phoo. Symbol γ - paricle or Paricle or p + e e e or elecro e or posiro. Where Ai eurio eurio (7) ui of Radio aciviy Bq = disieglaio/s curie = disieglaio/s 88

5 (8) Aciviy d I N d umber of Aoms or ucler i a Radio acive sample afer ime is give by Where is radio acive decay Cosa N No e Aciviy I = Io e Mass (9) Half life T Mea life T m mo e T 0.693T Or T.44 T (0) I - deccay Z decreasc by ad mass umber A decrease by 4 I β - deccay Z icrease by ad mass umber does o chage I deccay Z decrease by ad mass umber does o chage I emissio of r - ray or phoo, Z ad A does o chage. () Nuclear Fissio. The spiliig of a heavy ucleus io wo or more fragmes or moderae ad comparable sizes is called uclear Fissio e.g U Ba Kr 3 eergy q O () Nuclear fusio. The Process of uclear fusio cosiss i he combiaio of wo ligh uclei o form seble ucleus of mass less ha he oal iial mass. H H H e H H He 3 He He He H H If ay Q > 0 Exoergic Q < 0 Edoergic I ay uclear reacios cosveraio of momeum, charge ad eergy is mus. (3) Nucler reacio A (a,b) B or A+a B + b + Q A = Targe Nucleus a = Projeced Paricle B = resulig (produc) ucleus b = emied Paricle Q = eergy equal muss defec 89

6 MCQ For he aswer of he followig quesios choose he correc aleraive from amog he give oes. () I each of he followig quesio mach colum -I ad colum -II selec correc Aswer. Bohr aom model (P) fixed for he aom (B) Ioisaio poeial (q) Nucleus (C) Ruherford aom modal (r) saioary orbis (D) Thomso aom modal (s) I aom posiive ad Nagaive charge are disried uiformely. a s, b r, c q, d p (B) a r, b p, c q, d s (C) a p, b r, c s, d q (D) b p, c q, b r, d s () Read he followig quesio ad choose correc Aswer form give below. Boh asserio ad reaso are rue. Reaso is he correc explaaio of he Asserio (B) BOh asserio ad reaso are rue. Reaso is o correc explaaio of he asserio (C) Asserio is rue bu reaso is false. (D) Boh Asserio ad Reaso are false (i) Asserio :- I a radio-acive disiegraio, a elecio is emied by ucleus. Reaso :- elecco are always Prese i-side he ucleus. (ii) Asserio :- A elecio ad Posio ca aibilae each oher creaig Phoo Reaso:- Eleco ad Posio form a Paricle ad ai Paricle. (iii) Asseio:- A isolaed radioacive aom may o decay a all wha ever be is half ime Reaso:- Readioacive decay is a saisical Pheomea. (iv) Asserio :- Fragme Produced i he fissio of u 35 are acive Reaso:- The fragmes have abormally high Proo o euro raio (3) Each of he followig quesio coai wo salemes.choose correc aswer form he give below. (i) saeme-i:- Large agle scaerig of al-pha Paricle led o discovery of aomic ucleus. 90

7 sae me-ii :- Eire Posiive charge of aom is coceraed i he ceral core. saeme -I ad II are rue. ad saeme II is correc explaaio of saeme-i (B) saeme -I ad II are rue, bu saeme-ii is o correc explaaio of saeme I (C) saeme I is rue, bu sae me II is false. (D) saeme I is false bu saeme II is rue (ii) saeme-i amu=93.48 MeV saeme-ii I follows form E=mc (iii) saeme -I:-half life ime of riium is.5 years saeme-ii :- The fracio of riium ha remais afer 50 years is 6.5% (iv) saeme-i:- Nuclei of differe aoms have same size sae m e-i I :- R=Ro /3 (4) Mach colum I ad II ad chose correc Aswer form he give below. (a) Nuclear fusio (p) covers some maer io eergy (b) Nuclear fissio (q) geerally Possible for muelei low aomic umber (c) decay (r) geerally Possible for dcler high aomic umber (d) Exohermic uclear (s) Eesseially Proceeds by weak uclear for(c) reacio a p, b r, c d, d q (B) a d, b r, c p, d a (C) a q, b r, c d, d p (D) a r, b a, c p, d a (5) A radioaive sample has o acive aom a =o, a he rae of dissegraio a ay R ime is R ad he umber of aom is N, he raio. varies wih ime () as. N R N (B) R N (C) (D) R N R N 9

8 (6) The rasiio he sae =4 o = i a hydroge like aom resuls i ulraviole radiaio. Ifrared radiio will be obaied i he rasiio form 3 (B) 5 4 (C)4 (D) (7) I Bohr model he hydoge aom, he lowes orbil correspods o Iiie eergy (B) zero eergy (C) The miimum eergy (D) The maximum eergy (8) Eergy levels A, B, C of a cerai aom correspodig values of eergy i.e E A E B E c If,, 3 are wave leghs of radiio correspodig o he rasiio C B, B A ad C A. which of he followig is correc (C) 3 (B) 3 3 (D) 3 o (9) Accordig o Bohr's heory he radius of eleco i a orbi described by Pricipal quaum umber ad aomic umber Z, is Proporioal o. Z (B) Z (C) Z (0) The eergy of elecro i he h orbi of hydoge aom is expressed as E 3.6 ev The shores ad loges wave legh of lyma series will be. o o 90A, 3A (B) 35A,530 A (C) 5463A,7858A (D) Noe of hese () Number of specral lies i hydroge aom is. 6 (B) 8 (C) 5 (D) (D) 7 () I he uclear reacio X (, ) Li he aom X will be 4 He (B) B (C) B 0 (D) B (3) The ucleus which has radius oe hird of he radius of 89 Cs is 9 Be (B) 9 F (C) C (D) 7 Li 3 (4) A ucleus of 0 Po origially a res emis -paricle wih speed v wha will be 84 he recoil speed of he daugher ucleus 4 (B) 4 4 (C) 4 06 z (D) 06 9

9 (5) I he radius of a ucleus of mass umber 3 is R. he he radius of a ucieus of mass mumber 8 is 7 R (B) 9 R (C) 3 R (D) 7 R (6) The ucler of which of followig Pairs of uclei are isooes Se, Ca (B) Mo, Zr (C) Sr, Sr (D) Cd, S 0 6 (7) A elecro chage is Posiio from orbi =4 o he orbi = of a aom he wave legh of emied radiio i he form of R (where R is Redburg cosas) 6 7R (B) 6 R (C) 6 3R (8) The corol rod i a uclear reacor is made of (D) 6 5R uraium (B) Cadmium (C) pluomium (D) grabhie (9) which of he followig isoopes ormally fissoable 33 U (B) U 38 (C) U 35 (D) Np (0) which of he followig saeme is rue 9 Th Pa He P has 78 euros (B) (C) 9 U 90Th He 4 0 (D) 84 Po Pb () A Free euro decays io a Proo, a elecro ad (B) (C) (D) () The disace of he closes abbroach of a alpha paricle fired a a uclous wih kicic eergy K is ro. The disemce of he closes approach whe hw - paricle is fired a he same ucleus wih kieic eergy k will be. r o (B) 4r o (C) r o 4 8 (D) r o (3) which of he followig series i he specrum of hydroge alo lies i he visible legio of he elecro mageic specrum? Pasche (B) Lyma (C) Brake (D) Balmer (4) If 3.6 ev eergy is required o ioige he hydroge ao he eergy required o remove he elecro form = sae is Zero (B) 0. ev (C) 6.8 ev (D) 3.4 ev 93

10 (5) I N o is he origial mass of he subsace of hal lif 5 years, he amou of subsace lef afer 5 years is N o 6 (B) N o 8 (C) N o 4 (6) whe u-38 ucleus origialluy a les decay by emiig a -paricle havig a speed u he recoil speed of he resi-dual ucleus is. 4u 38 (B) 4u 38 (C) 4u 34 (7) A a cerai isa, a radioacive sample has a decay rae of 5000 dis-ieraio Per miue. Afer 5 miuer he decay rae is 50 dis-ieraios Per miue. The he decay cosa is (Per-mi ) 0. l 4 (B) 0.4 l 4 (C) 0.4 l (D) 0.8 l (8) A ucleus wih Z=9 emis he followig sequece,,,,,,,,,,,,, The Z of he resulig ucleus is 76 (B) 78 (C)74 (D) 8 (9) which of he followig ca o be emied i radioacive decay of he subsace? Helium-ucleus (B) Elecros (C) Neurios (D) Proo. (30) I he radius of 7 5 Al ucleus is 3.6 fm he radius of Te ucleus is early equal o 3 94 (D) (D) N o 4u 34 8 fm (B) 6 fm (C) 4 fm (D) 5 fm (3) which of he followig aom has he lowes ioizaio poeical? N (B) Ar (C) cs (D) 8 (3) If he bidig eergy of elecro i a hydroge aom is 3.6 ev, he eergy required o remove he elecro form he firs sae of Li + is. 3.6 ev (B) 30.6 ev (C).4 ev (D) 3.4 ev (33) The ioigaio Poeial of hydroge aom is 3.6 ev. A elecro i he groud sae absords Phoo of eergy.75 ev. How may dirrere specral lies ca oe expec whe elecro make a dow ward rasiio (B) (C) 6 (D) 4 (34) A radio-acive ucleus A Z X emis 3 -paricles ad Posirios. he raio of umber of euleuos o ha of Proos i he fial ucleus will be A Z 8 Z 4 (C) A Z 4 Z (B) A Z Z 4 (D) A Z 4 Z 8 O

11 (35) A -paricle of eergy mv bombards by a heavy uclear arge of charge ze.the he disace of close approach for he alpha ucleus will be Probprioal o 3 Z (B) 4 (C) m (D) (36) whe 7 Li ucler are bombarded by Proo ad he resula uclei are 8 Be, he 3 4 emied paricle will be euro (B) gamma (C) alpha (D) Bea (37) sarig wih a samble of Puer cu-66, 7 of i decays io Z, 5 miules he lef 8 of he samble is 5 mi (B) 7.5 mi (C) 0 mi (D) 5 mi (38) A -paricle of eergy 5 MeV is scaered hough 80 by a fixed uraium ucleus. The disace of he closes approach ucleus The disace of he closes approach is of he order of 8 0 cm 0 cm 0 cm 0 cm (B) (C) 0 (D) 5 4 (39) The bidig eergy Per ucleo of deuro H ad Lielium ucleus H e is. MeV ad 7.0 MeV.resbecively. If wo beuro ucler reac o form a sigle helium ucleus, he eergy released is 3.6 MeV (B) 6.9 MeV (C) 3.9 MeV (D) 9. MeV (40) The ucleus a res disiegrae io wo uclear pars which have heir velociies i he raio : The raio of heir uclar sizes will be 3 : (B) :3 (C) 3 : (D) : 3 (4) A radiaio of eergy E falls ormally o a Perec reflecig surface. The momeum raserred o he surace is. E (B) E E (C) (D) Ec c c c (4) I he followig uclear fusio reacio H H He 3 4 o he repalsive poeial eergy bewee he wo fusig ucler is J The Temperaure o which he gas mus be heaed is early (Bolzma cosm 3 K=.38 0 JK ) 3 0 K (B) 5 0 K (C) 7 0 K (D) 9 0 K 95

12 (43) 9 If he bidig eergy Per ucleo i 7 3Li ad 4 He ucler is 5.6 NeV ad 7.06 MeV respecively, he i he reacio eery of Prop mus be 4 P 3Li He (P here rere Proo).46 MeV (B) 39. MeV (C) 7.8 MeV (D) 39. MeV (44) 9 f mo is he mass of a isoope 7 8 0, mp ad m are he masses of a Proo ad euro respecively, he bidig eergy of he isoebe is (m 8m )c (B) (m 8m 9m )C o p (C) (m 7m )c (D) m c o (45) I gamma ray emissio form a ucleus o o p here is o chage i he proo-umber ad euro umber (B) Boh he umber are chages (C) oly Proo umber chage (D) oly euro umber chage (46) The half life ime of a radidacive elemes of x is he same as he mea life of aoher radioacive eleme Y. Iiially hey have same umber of aoms, he y will decay faser hea x (B) x will decay faser he y (C) x ad y will decay a he same rae a all ime (D) x ad y will decay a he same rae iially. (47) which of he followig rasiio i hydroge aoms emis Phoo of highes frequegy? = o =6 (B) = o = (C) = o = (D) =6 o = (48) A elecro Passig hrough a Poeial diffece of 4.9 v colides wih a mercury aom ad rasfer i o he firs excied sae wha is rasfer i o he firs excied sae. wha is he wave legh of Phoo correspodig o he fraiio of mercury aom o is ormal sae. 050 A (B) 935A (C) 55A (D) 40 A 96

13 (49) The bidig eergy Per ucleo for he Pare ucleus is Ead ha for he daugher uclei is E he E E (B) E E (C) E E (D) E E (50) The speed of daugher uclei is mc M m (B) C m m (C) C ( m) M (D) C m M m (5) Ligh form he discharge ube coaiig hydroge aom falls o he surface of a Piece of sodium. The kieic eergy of he fases phoo elecros emied form sodium is 0.73 ev. The work fucio for sodium is.8 ev. Ioigaio Poeial 7 of hydroge is 3.6 v ad he mass of hydroge aom is.670 kg. (i) The eergy of Phoo causig he Phoo eleceic emissio is 9 (B) J.9 0 J (C) J (D) 9 (ii).68 0 J The quaum umber of he wo levels i he emissio of he Phoos are (A ) =, =3 (B) =, =4 (C) =, =4 (D) =3, =4 (iv) I his rasiio chage i he agular momeum of elecro is (where h is Plak cosas ) h (B) h (C) h (D) 3h (v) The recoil speed of emiig aom caussig ha is a les before he rasiio is of he order of cms (B) 0 ms (C) 4 0 ms (D) ms (5) A ad B are wo radioacive subsae whose half lives are ad years respecively. Iiially 0 g of A ad g of B is ake. The ime afer which hey will have same quaiy remaiig is 3.6 years (B) 7 years (C) 6.6 years (D) 5 years (53) which of hese is a fusio reucio 3 4 H H He 0 (B) (C) U Pb 8 He 6 e C C g (D) Noe of hese 97

14 (54) The aciviy of a sample of a radio- acive maerial is a ime ad A a ime (where > ) if T is mea life is he A A (B) A A e ( )T (C) A A (D) (55) I he followig disieglaio series A T Ae 38 A 9 U x Z y The value of Z ad A respecively will be 90, 34 (B) 9, 36 (C) 88, 34 (D) 9, (56) gf 9 U udergoes sucesively 8 decays ad 6 decays he resulig ucleus is 06 Pb (B) 08 Pb (C) 4 Pb (D) Noe of hes (57) The eergy released by he fissio of oe uaium aom is 00 MeV. The umber of fissio Per secod required o Produce 3. w of Power is 0 0 (B) 7 0 (C) 0 (D) 7 0 (58) Radio carbo daig is doe by esimaig i he specime he amou of oridiary carbo sill prese (B) he radio of he amous of C C (C) he amou of radio carbo sill Prese (D) Noe of hese (59) The eery differece bewee he firs wo levels of hydroge aom is 0. ev. wha is he correspodig eergy differece for a sigly ioiged helium aom? 0. ev (B) 8.6 ev (C) 0.4 ev (D) 40.8 ev (60) The oal eergy of he elco i he firs excied sae of hydroge is -3.4 ev. wha is he kiaic eergy of he elecro i his sae? 6.8 ev (B) 3.4 ev (C) -3.4 ev (D) -6.8 ev (6) The wave legh of secod lie of Balmer series is m. wha is he wave legh of he firs lie of lyma saries? m (B) 79.6 m (C).6 m (D) Noe of hese (6) The iermos orbi of he hydroge aom has a radius 0.53 A. wha is radius of d orbi is?.a (B).06A (C).A (D) 0.6A 98

15 (63) If a hydroge aom emis a Phoo of wave legh, he recoil speed of he aom of mass m is give by m h (B) mh (C) mhλ (D) m h (64) A freshly PrePared radio acive source of half ime h emis radiaio of ieisiy which is 64 imes he Permissible safe level. The miimum ime afer which is would be possible o work safely wih his source is. 6 h (B) 4 h (C) h (D) 36 h (65) I R uherord experim e, he um er of Paricles sccered a 90 o agle are 8 Per mi. he he umber of Paricles a he agle 00 i Per mi will be 5 (B).0 (C) 50 (D) (66) The Ruherford revoluio Per secod made by a elecro i he firs Bohr orbi of hychoge aom is of he order of 5 0 (B) 0 0 (C) 0 0 (D) 9 0 (67) The half ime of a radioafive subsace is 0 mi, differece bewee Pois of ime whe i is 33% disiegeaed ad 67% dissieaed is approximaely 0 mi (B) 0 mi (C) 40 mi (D) 30 mi (68) The size of he aom is of he order of 4 0 m 0 m (B) 0 (69) The size of he ucleus is of he order of 0 0 m 0 m 0 m (C) 8 (D) 6 0 m 0 m (B) 4 (C) 9 0 m (D) 3 (70) The raio of aomic volume of uclear volume is of he order of 5 0 (B) 0 0 (C) 5 0 (D) 0 0 (7) Nucleo is commo ame for elecro ad euro (C) euro ad Posiro 4 (7) The ucler N ad 3 7 6C ca be desribed as (B) Proo ad euro (D) eufrom ad eurio Isooes (B) Isobars (C) Isoope (D) Isomer (73) Pluoiumdecays wih half life ime 4000 yer. if Pluoium is sored afer 7000 yes, he fracio of i ha remai (B) 9 (C) (D) 8 99

16 (74) The radio of miimum o maximum wave legh i Balmer series is 4 (B) 5 36 (C) 3 4 (D) 5 9 (75) If he bidig eergy of elecro i a hydroge aom is 3.6 ev, he eergy required o rem ove he elecro from he secod excied sae of L i ++ is 3.6 ev (B) 3.4 ev (C) 30.6 ev (D).4 ev (76) A radioacive subsace decays o h of is iiial aciviy i 40 days. he half life 6 of he radioacive subsace expressed i day is 0 (B) 5 (C) 0 (D) 4 (77) Complee he reacio o 9 U 56 Ba 3 o 90 Kr (B) Kr 89 (C) Kr 9 (D) Kr (78) 6C absorbs a eergeic euro ad emis a β Parical. The resulig ucleus is 3 N (B) N 4 (C) C 3 (D) C (79) wo deuros each of mass m fuse o form helium resulig i release of eergy E he mass of helium formed is E c E mc m (B) E c E C (C) m (D) m (80) wha Perce of origial radio acive subsas is lef afer 5 half life ime 3 % (B) 5 % (C) 6% (D) % (8) I which regio of eleromageic specum does he Lyma series of hydroge aom like x-ray (B) Irared (C) visible (D) ulraviole (8) I erms of Rydergi cose R. The wave umber of firs Balmer lie is 5R 36 (B) 8R 9 (C) R (D) 8R 0 (83) The hydroge aom ca give specral lies i he series Lyma, Balmer ad Pasche. which of he followig saeme is correc Lyma series is i he irared regio (B) Balmer series is i he ulravioe regio (C) Balmer series is i he visible regio (D) Pasche series is i he visible regio. 300

17 (84) The ioigaio eergy of hydroge aom is 3.6 ev. The ioigaio eergy of helium aom would be 7. ev (B) 3.6 ev (C) 54.4 ev (D) 6.8 ev (85) A gamma ray Phoo creaes a eleco- Posio Pair. If he res mass eergy of a elecro is 0.5 MeV. ad he oal kierc eergy 0.7 MeV, he he eergy of he gamma ray Phoo mus be 3.9 MeV (B).78 MeV (C) 0.78 MeV (D) 0.6 MeV (86) The masses of ero ad Proo are.0087 amu ad.0073 amu respecively. I he eufro ad Proos combis o form bidig eergy of he helium ucleus will be 4. MeV (B) 8.4 MeV (C) 7.3 MeV (D) 0.8 MeV (87) Large agle scaerig of - paricle could o be explaied by Thomso modal (B) Ruher Ruherford ad Thpmoso modal (C) Boh ruherford ad Thomoso modal (D) Neiher Ruhorford modal orthomso modal 3.6 (88) T he eergy of a elefor i h orbi of hychoge is exie he elecro form he firs orbi 4 h orbi is 3.6 (B)3.4 ev (C) 0.85 ev (D).5 ev ev. eergy required o (89) The aciviy of a radioacive sample is measured as o cous Per miue a =o ad No cous Per miue =5 mi The ime (i mi) a which aciviy reduces o half is valus is log e (B) 5log 5 0 (C) 5loge (D) 5 log 0 (90) A heavy uecleus a les breaks io wo frigmes which fly off wih velociies i he raio 8: The raio of radil of he frigmes is : (B) 4: (C):4 (D) : 6 (9) The bidig eergy Per ucleo of O is 7.97 MeV ad ha of 7 8 8O is 7.75 MeV The eergy (i-mev) required o remove a eurom from 7 8 O is 3.65 (B) 7.86 (C) 3.5 (D) 4.3 (9) The shape of he graph li is srigh Lie (C) Hyberbole curve (B) Parabolic curve (D) radom shabe curve 30

18 (93) The fig shows a eergy leves for he elecro i a cerai ao which rasiio i a represes he emissio of a Phoo wih mos eergy? I II IIIIV = 4 = 3 = = III (B) Iv (C)I (D) II (94) The Probabiliy of survival of a radioacive ucleus for oe mea life ime is s (B) e e (C) e (D) 3 e (95) A s he elecro i B ohr is orbi of hydroge aom Passes from sae = o =, he K.E. ad Poeial eergy chages as Two fold, also wo fold (B) four fold, wo fold (C) four fold, also four fold (D) wo fold, four fold A A A4 A4 (96) I he uclear decay below X Y B B Z Z Z Z,, (B),, (C),, (D),, (97) The wave legh of he firs lie of Lyma series for hydroge aom is equal o ha of hydroge aom is equal o ha of secod lie of Balmar series for a hydroge like io. The aomic umber Z of hydroge like io is (B) (C) 3 (D) 4 m (98) A ucleus x emis oe -Paricle ad wo Paricle. The resulig ucleus is m 4 Y m 6 (B) Y m 4 (C) Y m 6 (D) Y 4 (99) Af a cerai ime, a radio acive sample coais 0 0 aoms ad disiegraio rae is aom persec. whe 5 0 aoms are Lef o decay is disiegaio rae will be aom / s (B) 0 30 (C) aom / s (D) aom/s.0 0 aom / s 30

19 (00) excied hydroge aom emis a Phoo of wave legh i reurir o he groud sae The quaum umber of exiled sae is give by R R (B) R R (C) R(R ) (D) R(R ) (0) The radius of Ge uclide is measured o be wice he radius of 9 4 Be. The umber of ucleos i Ge are 7 (B) 78 (C)65 (D)80 (0)Mach colum I ad II colum I (a) sige of ucleus (P) Z colum II (b) umber of Proo i (q) 5 0 m a ucleus (r) (A-Z) (c) size of Aom (s) 0 0 m (d) Number of erous i a ucles a r, b s, c q, d p (B) a q, b p, c s, d r (C) a s, b r, c q, d p (D) b s, c p, c q, d r 303

20 KEY NOTE (B) ar, bp, cq, ds 6 A 5 (i) A 73 D 98 C (i) c (ii) b (iii) a (iv) d 7 A (ii) B 74 D 99 A 3 (i) a (ii) b (iii) c (iv) d 8 B (iii) B 75 A 00 B 4 (C) aq, br, cs, dp 9 D (iv) D 76 C 0 A 5 A 3 C 5 C 77 B 0 B 6 B 30 B 53 A 78 A 7 C 3 B 54 B 79 C 8 C 33 C 55 D 80 A 9 B 34 C 56 A 8 D 0 A 35 C 57 D 8 A D 36 B 58 C 83 C D 37 A 59 D 84 C 3 D 38 B 60 B 85 B 4 C 39 A 6 C 86 B 5 C 40 B 6 A 87 A 6 A 4 B 63 A 88 C 7 C 4 D 64 B 89 C 8 B 43 C 65 B 90 A 9 C 44 B 66 A 9 D 0 C 45 A 67 B 9 A B 46 A 68 B 93 D A 47 C 69 B 94 B 3 D 48 C 70 C 95 C 4 D 49 A 7 B 96 A 5 B 50 C 7 A 97 B 304

21 His () Bohr aom model saioary Orbis Ioizaio Poeial Fixed for he aom Ruherford aom model Nucleus Thomso aom model I aom posiive ad Negaive charge are disaibued uiformly. (4) Nuclear fusio geerally Possible for uclei low aomic umber Nuclear fissio geerally Possible for uclei high aomic umber - decay Eesseially Prcoceeds by weak uclear forces. Exohermic uclear reacio Coves some maer io oergy. dn d (5) disiegraio rae N R N he graph of R R N Cosa N will be seaigh lie. (6) 5 4 rasiio series of pasche which is fall i ifrared regio (7) As (C) The miimum eergy Orbi eergy () E 3.6 ev (8) As (C) fig From hc hc hc 3 A A A3 3 3 (9) Bohr radius r = h o e m r Z 305

22 (0) For, shores wave legh i Lyma series R mi 9A mi For, loges wave regh i Lyma series () R max 5 A max 7 () X (, ) Li (3) 3 X Li He By equaig Z ad A we ge A 7 4 Z o 3 X A 0 Z 5 B R R o ( A ) (4) Accordig o coservaio of momeum m v m v o 4v 06 v o 06 v 4v v 4v 06 Recoil speed of daugher ucleus is 4v 06 3 (5) R R (3) o R R (8) 3 3 R 8 (7) 3 R 3 R 3R (6) Isooes ucler have same euros i.e. A-Z are equal From he give pairs 34 se, 3Ca has same eurus 306

23 (7) R m (8) (9) (0) U 90Th + He () p e P e () A a disace of closes approach kieic eergy of - paricle = Poeical cergy of he sysem Kq q mv K ro (3) Kq q ro K Whe kieic eergy 9 ha ro ro 3.6 (4) Iigaio poeier (For hydroge) E = ev N o (5) T (6) Accordig o coservaio of momeum (7) N N e I I e o o 50= e e e l

24 (8) Aomic umber of fial ucleus = 9 - (o.of - Paricle) + (No. of Paricle) - (No.of Paricle) = (9) = 78 (30) use formula R= Ro 3 (3) 33 55Cs a mucleus havig highes Z umber, he ouer mos elecro are less i bidig wih uclera. Tha meam lowes bidig eergy. (3) Bidig eergy 3.6z For Li + Z = 3, = firs exied sae (33) E E E E E E E A 3 A e A (34) X X Y Z Z6 Z8 Number of ewfros = (A ) (Z 8) A Z 8 =A - Z - 4 Number of proom Z 8 No.of euros A Z 4 No.of Pr oos Z 8 308

25 (35) a disace of closes approach K.E = P.E (ze)(ze) ze mv ro 4 ro mv (36) ro m N where (37) No T (38) 4 (39) H H He B. E of Helium = 4(7)-[(.)+(.)] = = 3.6 ev eergy relewed is 3.6 ev (40) Accordig o cosveraio momeum m v = m v m v m v 3 r 3 r r r 3 3 r : r = : 3 (4) Here, surface is perface reflecor momeum of icide radiaio is E/C momeum of refleced rediaio is - E/C chage i momeum = - c E E C E = c Momeum rasered o he surface = E C 309

26 (4) E 3 KT (43) Eergy of proo ( H ) = 4 (7.06) 7(5.6) = = = 7. 8 (44) As (B) (45) (46) T x y x B.E mc mo 8mp 9m C T Y T Ty y x dx y T X T y y.44 x x y Accordig (47) = o = 6 absorbs phoo = 9 o = absorbs phoo = 6 o = emissio of phoo = o = emissio of phoo N Noe E E E ev E E ev. 4 E hf ' hf (48) eergy of elecro = ve 9 E J hc hc E 30

27 (49) (50) Mv mc m C V M V C ( m) m (5) (i) K max = hf - φ hf = K mux + φ (ii) Correspdig eergy level for.55 ev is =, = 4 As (B) (iii) Chage Agular momeum = 4h h h h h As (B) (iv) Accodig o coservaio of momeum momeum of phoo = momeum of lecoil alom. h mu v h hf E m mc mc (5) T m mb m m 0 m m 0 0 () log0 log year 6. 6 year 3

28 (53) As 3 4 H H He 0 (54) A A e 0 e o 0 A A A A e A 0 A e T A A e 0 T Now, A A e 0 T T T A e e A A e( ) / T 38 A (55) 9 U x ZY Th 34 9 U 90 9Y (56) 9 38 U d X 6 Y pb pb 8 or (57) Eergy released per uraium aom = 00 MeV (58) ev For -3 30x0 aom 3. 3 J λ =0 aoms -3 30x0 (59) The eergy level of hydroge aom correspodig o 0. ev is =, = correpodig egery for he's level for helium aom 3-6Z E= - E E E ( 3.6 4) E ev 4 3

29 (60) For ay sae Ze K.E 8E C ad Cagaomsl o Ze P.E=- 4πεo r (Toal eergy i he soe) E K.E P.E Ze E K. E 8 ru (6) For wave logh of secod lie of Balmer series 3R R R (B) 6 (B) 3R For wave legh of Firs lie of Luma series 3R R R 4 4 (L) 4 (L) 3R (B) 6 3R 4 (L) 3R 4 (B) (C).6 mm. (6) r For hydroge aom Z = z r r r 4 r 4r A. A 33

30 (63) Accordig comservaio of momeum momeum of phoo = momeum of rocil aom. h m (64) h m N No T log 64 log hrs (65) Number of scalerig - paricle a agle is N N s m si N N Ze o 4 si si 4 4 Q Q si Q 4 4 N si N 4 Q si si N N

31 (66) mr h For firs Bohr orbi = mr h h f 4 mr mr w h 5 f 0 mr (f ) h T (67) T 0 N N T o N N o T log.5 log (68) (69) (70) mi similary = =0mi mi. Volume of aom Volumeof uclear = 4 (0 ) 4 l (0 )

32 (7) (7) (73) T N 7000 No N No 8 (74) Use formula R Puiig = 4 5R 5 R R (75) For ay aom ay sae 3.6 E Z For Secod excied sae = 3 for Li, Z = 3 (76) E 3 6 (3) (3) 3.6ev N No 6 T 40 T 40 6 () T 40 log6 log T T T day.04 36

33 (77) A value & Z value kr o (78) 6C 0 7 N e (79) E ( m)c E (m M)C E C m M M m E C (80) a = o N = No T No N N No 6 T T 3 T 4 T 5 N No 4 N No 3 No N N0 N 3% 6 N0 N 3 (8) 5R (8) Wave umber = R R (83) 3.6Z (84) Ioigaio eergy of aom E ev For helum Z = 3.6 () =54.4 ev () (85) r e e The eergy of r - ray = Res mass eergy + K. E = ( ) = =.78 ev 37

34 (86) Mass degec m (mp m) MHe m ( ) m amu E m mev Mev (87) As Thomso model (88) As (c).75ev E E4 E ( ) ev 4 (89) I mea life (T) Res mass = No e T mi 5 N Noe No Noe 5 r 5 (90) e 5l 5 e 5 e 5 v V 8: 5log e Accodig o coservaro of momeum v 8 V m m m m 8 V r V r r r r r 3 38

35 (9) eergy reguired o remove a euro 7(7.75) 6(7.97) ev (9) (93) (95) k u k 4 k u 4 u k = 4k u = 4u K. E. four old P.E also four old. As (c) r (96) X Y B z B A A A4 A4 z z z As β,α,γ (97) RZ for ay aom 3RZ R() R (L) R 4 (L) (L) 4 3R 3RZ RZ R (B) (B) 3RZ (L) (B) 4 z 4 Z (98) X X Y m m 4 m4 39

36 (99) dn dn I dn df I N I N I N I N I f I 30 0 I N 30 N N N (00) R 5 R RR R R R R R R R R R (0) 3 3 o 0 R R (a) R R A 7 A 8 A (0) Size of ucleus 0-5 m No. of proo i a ucleus Z Size of aom 0-0 m No.of euri i ucleus (A-Z) As (B) a q, b P,c s,d r 30