PHYS 310 Final, Spring 1996

. Physics Depardinent Phys 3 _ ik ran Pays 310 Tune 29,1996 j : . Astrophysics Time: 3 hour | Rin yay Final Exam . 3 op 1 Name Tad NO se Remember tse nite words » Nature never deceives us, At ts alwa wt who dicave oursebves 4° J. Tada Bou eau -4- Please , Answer as many qutshons AS Yeu can wrthin tdg Givin time . (4) Virtal Theecem (2). Consiler tha “Behr modu 4f the hydeeyer adom, Shew that Be virial theorem as alsy satis Pad Aw thas Case. . (>) Consider a shar awn hydrashahe Aguilibrasiin . UU sing the qddahad¢ <daah on of Stale _ ¥ kk are constands P= kK g Ck, ¥ re OD : | shew that tha pelibial qravidehoml snbyy 52 : . J Hu shay AS . Jt = -3 CK DU, Whe Ube 6% urrdr as He dotel sudynad ANG} + Node that & wg ise snigy pr volume, Ve Fer P= 5/3 Your vesald sheuld be tu Aytmint abth Part (a). Explain why Hes agrumist, (2) Coletale He ackabuhe dew bara hare Grackint Vd for an Adtal nen degenyale FAs. Use te gentral A prassi in devived wy He Uchere . Ats Pressure As cominaded ky At raciahon Field ( P= a 7 *) . Show that the Auminosily ef the shay AS 9VbA by tha So called "Eddingdou Luminos; ty ; le = “res Hf ) Whivre FY is He toda mass vf th Stay, 2C 4's the — i _ ‘Opacihy 7 as the speed ef Leghtt , and Gy is dhs Mavitudhonal Cens haut . Hint : You nad As combine AAs £4uahon aT hydrostaArc Left Ui be ian wrth that e radiahon fanspotd . (4) Assamt simp Lintar meocdtl dor dhe deusity . Mn a slay, such as Str = % CA- Vey, > whtre 2 is He rads of tha star, and 8%. os He Conlval dusty . (a) Colcutale dhs mass funchon mC) Av dems al S. and R- (b) Use mer) dy oblan the Pressure R at Ae Gauker Xo the shay Lliwt : assume FAL sur fuce Pressure R=o. Use the equahon of hydveskikc “quilibyiut dd shew thet Te _ oS Gre . OR (C) Delvmine dha Contal pressuye an tka sun- Explain why das Gadad pressure’ durns cut Ab bo wiry high Compared und Earth's shaundards , i —3- . ; 2 (5) Cansjler tha Teacten ‘ C Cp, ge) Py and dssume the following data gives : X = 0-80 ( mass fractien ed hydregeu ) Twa 30 Cle Te = T/to’ k) S(o) = 4rho keV barn Caskophysical fachr) Saf = Sto) (A+ 7 $= 15 9/eu? (a) with these Anta , delermine the Kifedios of G agains + Fredon Caphare ; ib) Assume that tha 460 kev (Aab £HQy4) FLscnane AS thet dp laced dd 50 key C see Figure), Knowing. thet Be)» Compare 20 U>, urth CO Ee» as chtaintd undt- (a) . What is the duchy by which th Lifehine v4 al Ay veduced uf Such resonance Crld Lttst 2 onl Ep (Aub) — ye _ (6) Consicler the reachen Ie, (x, ¢) "Ne . Thr Level Scheme I dhe 24 e syskm As shown tu the figure, Assume 4A4 Lewaprrthay 2 Ash T= toe kK . E (meu) > (A) Caletale the mest effochve sktlar = AUN GY (E<) der this reachon » Which shale falls Au the Conley of the "Gamew — peak” 2 UF 3 Mey : (b) Zs this stake ad resonan@ 2, “toid | _ Tusk(4 Your answer, What ts te Signi freanee ef Your risul4 2 (Cc) What Lemprratare As niedacl #e- form 2 nile ths uciled shile ( 6.23, 07 ) 2 Could Hus shake serve as a véscvante ? _ (7) Tn dhe aA ppreximale ra badon dor +he tng y- Hervahou rake by te 30¢- preass : * _ . Al C3, CT) = Cy (Te) (£-) ) dheeming the value 4f 1. near Te =4, a IZ n dhe reachion ; 737 OE 3 | Ro 4 Pa N+ | dadermina the values ef the orb dal angular momentam ep that can Loom the be towing rasenente — shuks + os Ws OB - LDndicale which waves C 5,P,d,---) form tase resonanUs je dewn the congrgurahons dor the ProAms hrons Aa AN ° What ts the spin, od : t . NJ Am tha ground stale ( 2 Valuss possible ) 27 Hl mt: shall modud (2) Consi dr dat reachon : 4 37% 8 Li +P—° be 7 Be +4%, Tt has a vesenan at (Ep), = uyt kev Answer des Following 4ueshons M (A) What 1S toe tweidahon MnXtG 4 AM 3 Be yf tha Proton has tha above bn 9 4 | TCHR) Hint: you need FAs atomic at eV Erp Y s itn atomic mass uned (x) Pr ab) MCtLi) = #016005 U M(p) = 1.007025 U, (Be) = 8.005305 u Au = 935-4 Mev] masse ‘ v7 ()) . Nhy > tha num ber of purg s- nace, or ws fure F- nucle, $e small 2, Exphain the . 1 n w 4 derm ' Pure 5 -nucker , or Pare re nacler > (c) Given tha Lifelime of a nucteus Against nou bron cupture T= dot fears, and a typical average Cress sechon LTS = foo mitti barns pand a thermal Veloo ty wf am = 3x (3 curls 5 What Is dha corresponding nluken elias, +y nN, ( tn cw? / (A) Repeat Part (OC) ASSuming T,, =A ms (16 °secaal) « (0) rf the ntutron capture Cross suchen Lf Paral red - —Pbudens Wares as OC) ot ivhad Ic uw 2 the Aver ade Cross Sechun <g> 2 Hind s Use dds AXES 01S Presén Jed on He Lieder Ly gba lar.” e C) [9) Explain briefly dhe " aching Points | tncoundygl during As Y— proass nuclaesynddesis - (A) why is net possible At form (Ucanium or Thorium by dg S--Proass nudtesyntasis 2 —~ 6 JZeview Queshons —'t [O24 \ What a> dA main physi cul yvasony that the sum Can sucvive About Ag? Yas om the mam Sept le 2 [oz] Adee Laving Ay mam Sequcull , thy wvslihon wf Du sun (and obhay Sow mass skis ) abing thr, yed grant branch OR QB) 4 relahvely Long » ¢low cen this facd be related AB the Amter nel sdructure at Ais stage 2 [Q3\ wheat Ma kes the more massive Slavs hvo lve fas ler than dhe sun Oo thi RGB @ 7 TO #\ Cons cler the Solay. nutrhe spectrin fam quabrtakvely why dha PP —ntudines &B _ neat rinus have contin tcus specha . (a) | € ‘t aye (>) How do Gou tiplain dha dunt Lines Associa Hel cath Ah tBe _ neutyings é (c) Whitt reatrine ” Le Jemparatace 2, whe naa trina * Jug the weakest Mp india on Lemperature £ | Q5} Why thye is an ou Fer cenvechve Zong cn tha sun 2, that is which Phy sicok quan tity J - ‘ As raspons: ble dor the dormahan of He convechve Zo » which Chservahun snclicudes dhe Bisdeate ce} this Bone 2 |Q6. why de massive stars C hike & 5 Mg S dar) Aivilep CH Convechve cere MW BE Main Segubuld 2 —T- . (oz. The Ai leva fel IMD fram hydregén burning. ( effecdvety : UP —-» 4+He As about 26 Mev, whi ke the Gberaled Ang Y fram the 30 ~ process AS $37 HRV, (A) tHew much eer gy cere/g) AS gamed . from hy dregen buening 2 o Flew mach ergy carg/ a) AS gadud from the Bob- Preeess ? (») using phe vasulds smelt (A), esdimate tht Aa fe- dre vf a stor cle sng helium burning C The) re HAR Life- hme having hydrogen bar ning CT pe) g Llin fs You niu Aye Upr7ss 4 hieVv in avg. lass of a pred = 4.6% & lo "a , 18) \ihen cl Massive Sder “ Id My forms 0 Cere consisting of (en —Jeosp raclee , act ves mately uncer Joes Cpravs datrencl collapse . Why as Met possible du stabil 2e the star ad this stage 2% [9] What are the Phy sical condihons that make +he Ve pProvluchen Possible cn Stars by dhe 3 of — precess 2, List af Least th ret condih ons * The driving machansim for the "hedium flash " and dor "Thermal Pulsatong |! A's tha ZBol—Pprouss (A) Deseribe why the helium flash ts so Vielent, but not the thurmnal pulsation . (b) Where ave the Stars whith suffi- the ha Liam fas hh AM the Herfespruny — Lusseb Madam 4 ° where ane thy Stars war whibt -~R-