eBook Here Vn 12 Ly Thuyet Hat Nhan Nguyen Tu 140 Cautn 7756

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<p>Phn Ht nhn nguyn tBin son Nguyn Thanh H - 0972 64 17 64 - 1 - ChngHT NHN NGUYN T I.TNH CHT V CU TO HT NHN 1. Cu to ht nhn - Ht nhn tch in dngbng +Ze (Z l s th t ca nguyn t trong bng tun hon), kch thc ht nhn rt nh, nh hn kch thc nguyn t khong 104 105 ln - Ht nhn c to thnh bi hai loi ht l prtn v ntrn; hai loi ht ny gi chung l nucln. oPrtn, k hiu p, mang mt in tch nguyn t dng +e, khi lng 1,67262.10-27kg. oNtrn, k hiu n, khng mang in, khi lng 1,67493.10-27kg. oHt nhn nguyn tcha Z prtn v N ntrn. Tng s nucln trong ht nhn A = Z + N, A gi l s khi. - K hiu ht nhn: Ngi ta dng k hiu ha hc X ca nguyn t t tn cho ht nhn:XAZ hoc AX hoc XA. V d: Ht nhn Na c th k hiu bng cc cch sau: , hay,23 2311Na Na hoc Na23. - ng v oCc ht nhn ng v l nhng ht nhn c cng s prtn Z nhng c s ntrn N khc nhau, do c s khi A = Z + N khc nhau (c cng mt v tr trong bng h thng tun hon). V d:H11D H2121hayT H3131hayo Hyr c ba ng v l: + Hyr thngH11 chim 99,9% hyr thin nhin. +Hyr nng hay triD H2121hay chim 0,015% hyr thin nhin. +Hyr siu nng hay tritiT H3131hayht nhn ny khng bn, thi gian sng ca n khong 10 nm. oCacbon c nhiu ng v, trong ch c hai ng v bn lC126 vC136. Trong mt khi cacbon t nhin bn vng,C126 chim khong 98,89% vC136 chim khong 1,11%. - ng v phng x l ng v m cc ht nhn ca n c th phng ra cc tia phng x v bin i ht nhn ca nguyn t khc. V d: ng vTh He U234904223892+ 2. Khi lng ht nhn - Cc ht nhn c khi lng rt ln so vi khi lng ca electron; v vy khi lng nguyn t tp trung gn nh ton b ht nhn. tin cho tnh ton khi lng ht nhn, ngi ta nh ngha mt n v mi khi lng c khi lngcc ht nhn. n v ny gi l n v khi lng nguyn t, k hiu l u. - n v khi lng nguyn t u c gi tr bng 1/12 khi lng nguyn t ca ng vC126, v vy cn gi l n v cacbon. kg u272310 . 66055 , 110 . 023 , 6012 , 0.1211= =- Khi lng v nng lng oTheo h thc Anh-xtanh v mi quan h gia nng lng E v khi lng m ca cng mt vt c dng: E = mc2 oNng lng tnh ra n v eV tng ng vi khi lng 1u l:E = uc2 ~ 931,5 MeV=&gt;1u ~ 931,5 MeV/c2 (MeV/c2 cng c coi l n v o khi lng ht nhn) oCh : L thuyt Anh-xtanh, mt vt c khi lng ngh m0 (khi lng ca vt trng thi ngh), khi chuyn ng vi tc v, khi lng s tng ln thnh m (khi lng ng) vi2201cvmm=Khi nng lng ca vt (nng lng ton phn) lE = mc2 = 22201cvc m Nng lng E0 = m0c2 c gi l nng lng ngh v hiu s E E0 = (m - m0)c2 chnh l ng nng ca vt. II.NNG LNG LIN KT CA HT NHN. PHN NG HT NHN 1. Lc ht nhn - Cc nucln trong ht nhn ht nhau bng cc lc rt mnh to nn ht nhn bn vng. Cc lc ht gi l lc ht nhn. - Lc ht nhn khng phi l lc tnh in v lc ht nhn lun l lc ht gia hai prtn, gia hai ntron v gia mt ntron vi mt prtn. Lc ht nhn khng ph thuc vo in tch. - Lc ht nhn khng cngbn cht vi lc tnh in hay lc hp dn; n l mt loi lc truyn tng tc gia cc nucln trong ht nhn. Lc ny cng c gi l lc tng tc mnh, nhng ch tc dng khi khong cch gia hai nucln bng hoc nh hn kch thc ca ht nhn. 2. Nng lng lin kt ca ht nhn - Khi lng ca mt ht nhn lun nh hn tng khi lng ca cc nucln to thnh ht nhn . - chnh lch gia hai khi lng c gi l ht khi ca ht nhn, k hiu Am:Am = Zmp + (A - Z)mn - mx Trong :Am l ht khiZmp l khi lng ca Z prtn (A Z)mn l khi lng ca (A - Z) ntronmx l khi lng ca ht nhn X Phn Ht nhn nguyn tBin son Nguyn Thanh H - 0972 64 17 64 - 2 - - Nng lng lin kt ca mt ht nhn c tnh bng tch ca ht khi ca ht nhn vi tha s c2. Wlk = [Zmp + (A Z)mn mx]c2 Hay Wlk = Amc2 - Nng lng lin kt ring (k hiu AWlk) l nng lng lin kt tnh cho mt nucln. Ht nhn c nng lng lin kt ring cng ln, th cng bn vng. 3. Phn ng ht nhn - Phn loi: Phn ng ht nhn thng chia lm hai loi: + Phn ng t pht l qu trnh phn r ca mt ht nhn khng bn vng thnh cc ht nhn khc. + Phn ng ht nhn kch thch l qu trnh cc ht nhn tng tc vi nhau to thnh cc ht nhn khc. - c tnh ca phn ng ht nhn: + Bin i cc ht nhn. + Bin i cc nguyn t.+ Khng bo ton khi lng ngh. - Cc nh lut bo ton trong phn ng ht nhn oBo ton in tch: Tng in tch ca cc ht tham gia phn ng bng tng in tch ca cc ht to thnh sau phn ng.(A B C DZ Z Z Z + = + ) oBo ton s nucln (bo ton s A): Prtn c th bin thnh ntrn v ngc li nhng s nucln l khng i. (A B C DA A A A + = + ) oBo ton nng lng ton phn: Tng nng lng ca mt h kn c bo ton.( ) ( ) ( ) ( )A A B B C C D DE E E E E E E E + + + = + + +oBo ton ng lng: ng lng ca mt h kn c bo ton. A B C Dp p p p + = + - Nng lng phn ng ht nhn:Gi tng khi lng cc ht nhn trc phn ng l mtrc, tng khi lng cc ht nhn sau phn ng l msau + Phn ng ta nng lng khi mtrc &gt; msau, nng lng ta ra c tnh bng cng thc:Wta = W = (mtrc msau)c2 + Phn ng thu nng lng khi mtrc &lt; msau, nng lng thu c tnh bng cng thc:Wthu = |W| = -W III.PHNG X 1. Hin tng phng x - N: Phng x l qu trnh phn hy t pht ca mt ht nhn khng bn vng (t nhin hay nhn to). Qu trnh phn hy ny km theos to ra cc ht v c th km theo s pht ra cc bc x in t. Ht nhn t phn hy gi l ht nhn m, ht nhn c to thnh sau phn hy gi l ht nhn con. - Cc dng phng x+ Phng x o Ht nhn m X phn r to thnh ht nhn con Y, ng thi pht ra tia phng x o theo phn ng sau: He Y XAZAZ4242+ hay c th vit He XAZAZ42 o *Bn cht l chm ht nhn hli He42 gi l ht o. * Tnh cht: mang in tch (+2e) nn tia o lch v bn cc m ca t in. Ht o phng ra vi vn tc v ~ 107m/s, lm ion ha mi trng v mt dn nng lng, vvy n ch i c ti a trong khng kh 8cmv kh nng mxuyn yu. + Phng x |- Phng x |- l qu trnh pht ra tia |-. Tia |- l cc dng electron ( e01 ). Dng tng qut ca qu trnh phng x:Y XAZAZ 1 + | + Phng x |+ l qu trnh pht ratia |+.Tia|- l cc dng pzitron ( e01). Pzitron ( e01)c in tch +evc khi lng bng khi lng electron, n l phn ht ca electron. Dng tng qut ca qu trnh phng x:Y XAZAZ 1 +| + Tnh cht: Cc ht | phng ra vi vn tc v ~ c = 3.108m/s, cng lm ion ha mi trng nhng yu hn tia onn tia | c th i xa hng trm mt trong khng kh v kh nng m xuyn mnh hn tia o. + Phng x * Bn cht: l sng in t c bc sng ngn ( &lt; 0,01nm), ng thi l chm phtn c nng lng cao. *Tnhcht: tiackh nngmxuynrtln,cthiqualpchdyhngchccmvgy nguyhimchocon ngi, v khng mang in nn n khng b lch trong in trng v t trng. 2. nh lut phng x - c tnh ca qu trnh phng x + C bn cht l qu trnh bin i ht nhn+ C tnh t pht v khng iu khin c+ L mt qu trnh ngu nhin - nh lut phng x + Xt mt mu p.x c N h.nhn ti thi im t. Ti thi im (t + dt) s h.nhn gim i v tr thnh (N +dN) vi dN &lt; 0. + S ht nhn phn hy trong khong thi gian dt l (-dN)-dN = Ndt Trong l mt hng s dng gi l hng s phng xdtNdN =+ Gi N0 l s ht nhn ca mu phng x tn ti lc t = 0, s ht nhn N vo thi im t &gt; 0 l:N = N0te Phn Ht nhn nguyn tBin son Nguyn Thanh H - 0972 64 17 64 - 3 - - Chu k bn r: Mi chtphng x c c trng bi mt thi gian T gi l chu k bn r, c sau mi chu kny th s nguyn t ca cht y bin i thnh cht khc. 693 , 0 2 ln= = T3. ng v phng x nhn to - Ngoi cc ng v p.x c sn trong t nhin, ngi ta ch to c nhiu ng v p.x gi l ng v p.x nhn to. - Phng x nhn to v phng php nguyn t nh du + Bng phng php to ra phng x nhn to, ngi ta to ra cc ht nhn phng x ca cc nguyn t X bnh thng, khng phi l to ra cht phng x theo s tng qut sau:X n XAZAZ1 10+ ++ XAZ1 +lccngvphngxcaX.Khitrnlncchtnhnbnhthngkhngphngx,cchtnhnphngx XAZ1 +cgilccnguyntnhdu,chophptakhoststnti,sphnb,schuynvncanguyntX. Phng php nguyn t nh du c nhiu ng dng trong sinh hc, ha hc, y hc ... - ng v 14C, ng h Tri t + tng cao kh quyn, trong thnh phn ca tia v tr c cc ntron chm (tc vo c vi tram mt trn giy). Mt ntron chm khi gp ht nhnN147(c trong kh quyn) to nn phn ng: p C N n1114714710+ +C146 l mt ng v phng x |-, chu k bn r 5 730 nm. + Trong kh quyn c ccbon ioxit: Trong cc hnhn cacbon y c ln cC126 vC146(t l khng i:C146chim 10-6 %) + Cc loi thcvt hpth CO2trongkhngkh, trong cacbon thng v cacbon phng x vi tl 10-6%. Khi loi thc vtycht, khngcn s hp th CO2 trong khngkhvC146khngcn tisinhtrongthcvtna.VC146 phng x nn lngC146 gim dn trong thc vt . So snh cc t l cho php ta xc nh thi gian t lc loi thc vt cht n nay. Phng php ny cho php tnh cc khong thi gian t 5 n 55 th k. IV.PHN NG PHN HCH 1. C ch ca phn ng phn hch - Phn ng phn hch l g ? Phn hch l phn ng trong mt ht nhn nng v thnh hai mnh nh hn. - Phn ng phn hch kch thch. + Xt cc phn ng phn hch ca cc ht nhn:U23592,U23892,Pu23994 v l nhng nguyn liu c bn ca cng nghip nng lng ht nhn. + truyn nnglngkch hot cho ht nhn X l cho mt ntron bnvo X X bt ntron . Khibtntron, ht nhn X chuyn sang mt trng thi kch thch, k hiu X*. Trng thi ny khng bn vng v kt qu xy ra phn hch. n + X X* Y + Z + kn(k = 1, 2, 3) + Ht nhn X* v thnh hai mnh km theo mt vi ntron pht ra. + Qu trnh phn hch ca X khng trc tip m phi qua trng thi kch thch X*. 2. Nng lng phn hch - Xt cc phn ng phn hchU23592 sau y: n I Y U U n10138539539* 2369223592103 + + +n Sr Xe U U n10953813954* 2369223592102 + + +- Phn ng phn hch ta nng lng + Cc php tnh ton chng t phn ng phn hch trn l phn ng ta nng lng, nlng gi l nng lng phn hch + V d: S phn hch ca 1g 235U gii phng mt nng lngbng 8,5.1010J, tng ng vi nng lng va 8,5 tn than hoc 2 tn du ta ra khi chy ht. - Phn ng phn hch dy chuyn. + Saumi ln phn hch, c k ntron c giiphngn kch thch cc ht nhn 235Ukhc tonn nhng phnhch mi. Sau n ln phn hch lin tip, s ntron gii phng l kn v kch thch kn phn hch mi. + Khi k &lt; 1 phn ng phn hch dy chuyn tt nhanh. + Khi k = 1 phn ng phn hch dy chuyn t duy tr v nng lng pht ra khng i theo thi gian. + Khi k &gt; 1 phn ng phn hch dy chuyn t duy tr v nng lng pht ra tng nhanh v c th gy nn bng n. + Mun cho k &gt; 1, khi lngca cht phn hchphi ln s ntron b bt nh hn nhiu so nhiu so vi s ntron c gii phng. + Khi lng ti thiu ca cht phn hch phn ng phn hch dy chuyn duy tr c trong gi l khi lng ti hn. 3. Phn ng phn hch c iu khin - Phn ng phn hch ny c thc hin trong cc l phn ng ht nhn, tng ng vi trng hp k = 1. - m bo cho k = 1, ngi ta dng nhng thanh iu khin c cha bo hoc caimi. - V bo hoc caimi c tc dng hp th ntron nn khi s ntron tng qu nhiu ngi ta cho cc thanh iu khin ngp su vo trong l hp th ntron tha. Nhin liu phn hch trong cc l phn ng thng l 235U hay 239Pu. - Nng lng ta ra trong l phn ng khng i theo thi gian. V.PHN NG NHIT HCH. 1. C ch ca phn ng nhit hch - Phn ng nhit hch l phn ng trong hai hay nhiu ht nhn nh tng hp li thnh mt ht nhn nng hn. - iu kin thc hin Phn Ht nhn nguyn tBin son Nguyn Thanh H - 0972 64 17 64 - 4 - + Nhit cao (50 100 triu ) chuyn hn hp nhin liu sang trng thi plasma. + Mt ht nhn trong plasma (n) phi ln. + Thi gian duy tr trng thi plasma (t) nhit cao 100 triu phi ln. Vy, 316 14) 10 10 (cmsn &gt; tl iu kin c bn xy ra phn ng ht nhn. 2. Nng lng nhit hch Nng lng ta ra bi cc phn ng nhit hch c gi l nng lng nhit hch. 3. Phn ng nhit hch trn Tri t - Trn Tri t, loi ngi to ra phn ng nhit hch khi th bom H v ang nghin cu phn ng nhit hch c iu khin. - Phn ng nhit hch c iu khin MeV n He H H 6 , 1710423121+ + +- Mun tin hnh c phn ng nhit hch cho cc ht nhnH21 vH31 th phi tin hnh theo ba cch: + a nhit ln cao. + Dng cc my gia tc. + Dng chm laze cc mnh. Phn Ht nhn nguyn tBin son Nguyn Thanh H - 0972 64 17 64 - 5 - HT NHN NGUYN T I. HT NHN NGUYN T 1. Cu to ht nhn: == + = = = 2719271, 67262.10 proto n 1, 6.10 c ta o ne n t 1, 67493.10( - ) ntron 0 :khong mang ien ppAZnpm kgZq CXm kgN A Zq 2. n v khi lng nguyn t ( u ):= = =271, 0072761 1, 66055.101, 008665pnm uu kgm u 3. Cc cng thc lin h: a. S mol:23A;A: khoi lng mol(g/mol) hay so khoi (u):khoi lng N: so hat nhan nguyen t;N 6, 023.10nguyen t/molAAAmNAnmANNmNnNNA== = = = 4. Bn knh ht nhn:11531, 2.10 ( ) R A m=II. NNG LNG HT NHN 1. ht khi:00( ) :khoi lng ca c nuclon rieng lep nm Zm A Zmm m m= + A = 2. H thc Einstein: 2E mc = ; 21 931, 5 uc MeV = ; 131 1, 6.10 MeV J=3. Nng lng lin kt, nng lng lin kt ring: a. Nng lng lin kt:2E mc A = Ab. Nng lng lin kt ring::tnh cho mot nuclonEAoA=Ch : H.nhn c s khi trong khong t 50 n 70, n.lng lin kt ring ca chng c gi tr ln nht vo khong 8,8 MeV/nu III. PHNG X 1. nh lut phng x:= === =0000 ln22 ;vi:hang so phan ra( ) 2ttTttTNN N em Tsm m e 2. phng x:00100 0ln2;vi:hang so phan ra ( ) 2; ( );1 3, 7.10 Bq ttTHH H eTsH N H NBq Ci = = == = = 3. Th tch ca dung dch cha cht phng x: 002tTHV VH=Trong : la the tch dung dch chaV HChu k bn r ca mt s cht Cht phng x 126Cacbon C 168Oxi O 23592Urani U 21084Poloni Po 22688Rai Ra 21986Radon Ra13153Iot I Chu k bn r5730 na m T= 122 s T= 87, 13.10nam T=138 ngay T= 1620 nam T= 4 s T= 8 ngay T=3. Cht phng x b phn r: a. S ht nhn nguyn t b phn r: 0 0(1 )tN N N N e A = = b. Khi lng ht nhn nguyn t b phn r: 0 0(1 )tm m m m e A = = Ch : S ht nhn nguyn t to thnh bng s ht nhn nguyn t phng x b phn r Phn Ht nhn nguyn tBin son Nguyn Thanh H - 0972 64 17 64 - 6 - B:NC AA B C N N + = = A ; khng c nh lut bo ton khi lng. 4. Cc tia phng x:a. Tiao : 4 42 2la hatHe o b. Tia| : 0 01 10 01 1 ( ) ( )la pozitron eco hai loaila electron e||+ c. Tia : C bc sng ngn 1110 m &lt; , c nng lng rt ln IV. PHN NG HT NHN1. Phn ng ht nhn: C A B DA B C DA A A AZ Z Z ZA B C D + +2. Cc nh lut bo ton: a. nh lut bo ton in tch: A B C DZ Z Z Z + = + b. nh lut bo ton s nuclon: A B C DA A A A + = + c. nh lut bo ton nng lng:( ) ( ) ( ) ( )A A B B C C D DE E E E E E E E + + + = + + +d. nh lut bo ton ng lng: A B C Dp p p p + = + 3. Cc cng thc lin h: a. ng nng: = = =2 27 131; ( );1 1, 66055.10 ;1 1, 6.102E mv m kg u kg MeV J b. ng lng: hay; p mv p mv p v = = || c. Lin h: 22 p mE =4. Nng lng trong phn ng ht nhn:Khi lng cc ht nhn trc phn ng: 0 A BM m m = +Khi lng cc ht nhn sau phn ng: C DM m m = + a. Phn ng ta nng lng: 0M M &gt;Nng lng ta ra l: 20( ) 0 E M M c A = &gt;b. Phn ng thu nng lng: 0M M &lt; Nng lng thu vo l: 20; ( )E E E E M M c = A + A = Edited by Foxit ReaderCopyright(C) by Foxit Software Company,2005-2008For Evaluation Only.Phn Ht nhn nguyn tBin son Nguyn Thanh H - 0972 64 17 64 - 7 - BI TP TRC NGHIM Cu 1.Pht biu no sau y l ng? A. Ht nhn nguyn tXAZ c cu to gmZ ntron v A prton. B. Ht nhn nguyn tXAZ c cu to gmZ prton v A ntron. C. Ht nhn nguyn tXAZ c cu to gm Z prton v (A - Z) ntron. D. Ht nhn nguyn tXAZ c cu to gm Z ntron v (A + Z) prton. Cu 2.Pht biu no sau y l ng? A. Ht nhn nguyn t c cu to t cc prton.B. Ht nhn nguyn t c cu to t cc ntron. C.Htnhnnguyntccutotccprtonvcc ntron. D. Ht nhn nguyn t c cu to t cc prton, ntronv electron. Cu 3.Pht biu no sau y l ng? A.ngvlccnguyntmhtnhncachngcs khi A bng nhau. B.ngvlccnguyntmhtnhncachngcs prton bng nhau, s ntron khc nhau. C.ngvlccnguyntmhtnhncachngcs ntron bng nhau, s prton khc nhau. D. ngv lcc nguyn tm ht nhnca chng ckhi lng bng nhau. Cu 4.nvnosauykhngphilnvkhilng nguyn t? A. Kg; B. MeV/c;C. MeV/c2;D. u. Cu 5.nhngha nosauyvnvkhi lngnguyn t u l ng? A. u bng khi lng ca mt nguyn t HyrH11. B.ubngkhilngcamthtnhnnguyntCacbon H11. C.ubng 121khilngcamthtnhnnguynt CacbonC126. D. u bng 121 khi lng ca mt nguyn t CacbonC126. Cu 6.Ht nhn HU23892 c cu to gm: A. 238p v 92n;C. 92p v 238n; B. 238p v 146n; D. 92p v 146n. Cu 7.Pht biu no sau y l ng? A. Nng lng linkt l tonb nng lngcanguyn t gm ng nng v nng lng ngh. B.Nnglnglinktlnnglngtarakhiccnuclon lin kt vi nhau to thnh ht nhn. C. Nng lnglinkt lnnglngtonphncanguyn t tnh trung bnh trn s nuclon. D. Nng lng lin kt l nng lng lin kt cc electronv ht nhn nguyn t. Cu 8.Ht nhn teriD21 c khi lng 2,0136u.Bitkhi lngcaprtonl1,0073uvkhilngcantronl 1,0087u. Nng lng lin kt ca ht nhnD21l: A. 0,67MeV;C.1,86MeV; B. 2,02MeV;D. 2,23MeV. Cu 9.Ht nhnCo6027 c cu to gm: A. 33 prton v 27 ntron;B. 27 prtonv 60 ntron. C. 27 prton v 33 ntron;D. 33 prton v 27 ntron. Cu 10.HtnhnCo6027ckhilngl55,940u.Bitkh...</p>