ACT Past Papers with Answers

Paper 81 · ACT December 2003 · Form 61E · Science Test

5m 吾 昏 .0 J O ss, 且 县 m 2 I Im bottom of 中乒心t > CaCO, No仁：0芯＄令而叩isoot切scaJc. Figure 2 Flow> 1 and Fi心”o2eda西d fn,m J．儿叩wsetaI.，An/ntroduc 如幻已,vironm,n田O诏,mstry. 01996 by Bia改WellScience.Ltd.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Based on Fig叩l, which_.of the following best 上scribes the evoln比ooary rel丑口心!rip b又weeri bony 丘hes, amphibians,血dre芦ilcs? amphibi立s evolved氐mreptil心． evolved如m amphibians. i扛比evolved仓om bonyfi妇． D, Reptile, evolved丘om bony五shes, and bony fishes evol>Cd如m amphibians.

Paper 81 · ACT December 2003 · Form 61E · Science Test

According·to Table I印d Figure I, from山. be护血ng of the Silurian period to the end of the Devo,i扭 period, the abandance忒比•jawle,s vertebral.cs, 兄 让creased only. G, decreased only. 丑increas吐妇dee～压ed.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Floweringpl辽ts酝ta 平 aredbefore the血t bumaus appeared釭dafter山e江st bi呻appeared. B压ed叩 th辽泣formatiou红d Table 1, floweriug pl扛ts most likely f°,.rst appe如d during which of the following 严ods7 `cr..,E 39 GO ON TO THE NEXT PAGE. 40 0 0 0 0 Passage IJ Eaaporites are m立raLs that precipitate (crystalli，e) during thepa.rtwor Iotal ev叩心oa ofseaw”“ 节icaJ cvapmICS are haIUe (NaCl)，盯P产m (�SO, • 2_H,O), ca!citt (CaC03),..d the "2ineral皿立叩比own as b让em 呻S, which COD吐＄potauium (K)...d magn玉um (Mg） compounds. Figure I shows the order of evaporite pre­ cipitation as a colwun·ofseaw如1丘deep evapora_tes 印d the迳血ity of the re亚血垃g seawa立as evaporation progress心．Figure 2 shows the cross section_of a巧 ． aJ evapontedepo豆1formedfroma1丘勹了血。尽－ W亚r. Table.I shows lbe solobilities釭d itie. ofsome evaporites. 0 0 0 0 4 oosssectiontlrrough 叩回tN飞°血北poSll fom,od fromthe evap,立on ofalkm吟colu皿of父awa丘 topof - d叩osit

Paper 81 · ACT December 2003 · Form 61E · Science Test

Accor如g to F屯are I, the seaw量比r's salinlry at the poi.ct when 25% of tbe se,watcr colamn bad evapo­ ntcd would most likely be: J, greater th旺80 g/L. 40 GO ON TOTHE NEXT PAGE. 40 0 0 0 0 0 0 0 04

Paper 81 · ACT December 2003 · Form 61E · Science Test

If Figure 2 is ·typical of e邓porite deposits. thegrcatcs1 加吐nc5s of皿yevapo土e deposit willbe composed of wltich 2 cvaporites7

Paper 81 · ACT December 2003 · Form 61E · Science Test

lo the deseriptioo of the Shell Model, a oueloos with 20 frotons and 19 ncntro压is discu.ssed. Whi!e the ouclcus is'"'2:ic面th respect to protoos, it ii not magicwithre吓cctto neotron斗比c...＄c: neutrons. ma.ximom oumberofneutrons. J, ooly ooe of还shells COD也IDS thc ma.ximum numb”°oeOlrons. • Accordiog to the Shell Model, a nocle心would most lli:cly be sp比ri叫it山e tota.l n皿1bcrs of pro10n, 1.ttd oeutrons in its first.2虹lls equaled w压ch of中e fol­ lowiog values? (Notc: Assume th吐S证Us 3 and higherare empty.) B, 6 proto心， 6neo丘心 心．A supporter of theLiquid Drop Model favors the view thatoncleons in a oncleus iD比mwith ..ch other血 如molecules m • drop.of water. A snpporter of the 翋扭odel了ould~futetb.is dew11Sing咖ch ofthe follo吐g obsetvatio正？ nnclei can cause the nnclcito no妇o fission. mmyelementsunimpe士d. ENOOFTEST4 STOP! DO NOT RETURN TO ANY OTHER TEST. Sf Englis h Mathematics Readling Science 1 D 36 F 1 D 36 J 1 D 1 B 2 H 37 B 2 K 37 D 2 G 2 F 3 B 38 H 3 D 38 J 3 D 3 C 4 F 39 D 4 K 39 B 4 G 4 H 5 D 40 J 5 A 40 J 5 A 5 B 6 F 41 C 6 K 41 A 6 H 6 G 7 D 42 J 7 B 42 G 7 B 7 A 8 H 43 A 8 G 43 C 8 J 8 H 9 B 44 F 9 C 44 K 9 C 9 D 10 H 45 B 10 H 45 E 10 H 10 G 11 D 46 J 11 D 46 H 11 C 11 H 12 F 47 A 12 H 47 B 12 G 12 H 13 B 48 F 13 A 48 J 13 A 13 D 14 G 49 C 14 G 49 A 14 J 14 J 15 A 50 H 15 C 50 H 15 D 15 D 16 J 51 D 16 G 51 E 16 F 16 F 17 A 52 J 17 A 52 H 17 C 17 A 18 J 53 D 18 G 53 A 18 F 18 J 19 C 54 G 19 D 54 G 19 B 19 C 20 J 55 A 20 J 55 E 20 J 20 H 21 D 56 H 21 E 56 F 21 A 21 B 22 F 57 D 22 G 57 E 22 G 22 H 23 A 58 H 23 A 58 F 23 C 23 C 24 G 59 B 24 H 59 B 24 G 24 G 25 C 60 G 25 A 60 G 25 C 25 A 26 G 61 A 26 K 26 J 26 F 27 B 62 H 27 D 27 B 27 A 28 F 63 B 28 H 28 G 28 F 29 A 64 J 29 C 29 A 29 D 30 H 65 B 30 H 30 F 30 G 31 B 66 G 31 E 31 C 31 B 32 G 67 C 32 F 32 J 32 J 33 B 68 H 33 D 33 B 33 B 34 F 69 D 34 H 34 F 34 H 35 D 70 H 35 B 35 A 35 B 71 A 36 G 36 F 72 F 37 C 37 C 73 D 38 F 38 H 74 H 39 B 39 D 75 A 40 J 40 G Explanation of Procedures Used to Obtain Scale Scores from Raw Scores On each of the four tests on whl中仰marked any responses, the total numb忒4corTect啦ponses ytelds a raw score, Use th. lablebe如to.convert your raw scores沁scale scores. For ea中也s� IOGalo and circle your raw sec『eo『the range of raw scores !hat比如des It In the址le below. Then, read across to either outs心• column of !he lable and ci心e the scale score that corrospondS to that raw沁ore. As ycu detar· mine your seals scores, enter them In归bfenks pmvfded on 妇nghL The highest possible scale score for each test is 36. The lowest po述ble scale score for any test on的ich问 mar如any龙Spons..1s1: Next, compute the Composita scoreby叩raging the four scaJe实叩s:To do this, add your fourscalescores and divide 如sum by4. II妇resulUngnumber ends In • fractlon, round ft off沁加nea,ostwhole n叩如.(Rounddown anyfraction耘s 们an one-half, round叩叩fractlon 1hat比one-half or mora.) En酝加s l'IJlllbar In the blank. This is)'0Uf'Composite score. The high够I poss回e Composite s09re is 38. The lowest poss!- • ble Composilo sccre is1. ACT Test 61E Engflsh Malhema丘cs Reading 实ence Sum of $CO芯 Composll8比ONI (sum今4) Your Scale Score 阰延Ifyou left a.testcompletely blank and ma位dnoltems, 心not lb>t a scalescore for眨t巳st. ff any testwas completely blenk, do not oak:认忒• a Composite score. R叩S已汀妇 和．佑 Test1 Test2 scon, 氐gllsh Malhematics 36 75 妇 35 元74 58 34 72 56-57 33 71 55 32 70 54 31 69 52芯 30 68 51 29 ' 66芍 49-50 28 氐 47-48 27 63-64 4牛46 26 61笠 42-43 25 6g七0 40-41 24 57-58 37.39 23 55呻56 3士 34 36 百 巳 50-52 3砬 20 47-49 30-31 19 11 -16 27-29 18 41心 25-26 .17 `}如 21-24 16 35-37 18-20 15 324 1牛17 14 29-31 11·13 13 忠28 09-10 12 24-25 07逑 11 22·23 06 10 20-21 05 g 18-19 04 8 15-17 03 7 12-14 6 10,11 02 5 妇9 4 妇7 01 3 妇5 2 位心3 1 00-01 00 52 Tesl3 Reading

Paper 81 · ACT December 2003 · Form 61E · Science Test

Which of山c following statements about山e onset of signific扭t evapo由e pre”pit.ation江扣ppo血by出e dat.a io Fi即re·1 ? Significant evaporitcp志pitation be血s: evapora比d. evaporated.

Paper 81 · ACT December 2003 · Form 61E · Science Test

W压ch_o;中e fallowing虹匕皿血s about the precipi也－ tion of evapori氐is巳pported by the d吐ainFigurc 1 亚dT吐le I ?Tbc丘文ovaporite to precipi比比omof scawate<江the evaporile with如： 叫 官 3 忑 巨 s o a p 江 仙 令 3 P ) 兰 m o p 工 ,er.“巴 41 GO ON TO THE NEXT PAGE. 4o Passage Ill Ep叩r"如areused邸吐hesiv"皿d eoa血gs. They are fonn吐wbeo molecul心C叩tainiug two epo巧肛叩p, 江e reacted, or cured, with molec让～～ntaining two ami心 贮0叩s（比e Fi砰元1) 。 。 。 。 。 。 。 100 。 \1\/ /C- 气JCX)'gonp ／女 amiDegrwp Fi严l The% C盯• le a mea.sure of止e cample血"c ofthe renc­ tion that forms ao epoxyresin. All cpo灯resin比dens心it cares. 尽 ： 上 一·.－- － 尸 ， 一 一：一一一一： 一：一 一；－ －尸 ;：40 正200 Fi炉工e 3 Figures 2 and 3 show bow the'll叩元cb功ges timcw归叩al血ouats ofEl ·orE2 (compol1!lds oo, 叩two叩oxy groups)釭C屯,d with Al,心，A3., (compo口uds cootaioiog two amine groaps) at 2 Figure 4 shows bow temperature affects the'I, cu 诅entical ；2041) 0 0 / ／ 加0 ；；三0200 E严e4 Figure 2

Paper 81 · ACT December 2003 · Form 61E · Science Test

Based on the d吐• in Figwe 3. as time increased from 0 min ro 180 min. the% ci= ofE2 cnred with Al: ^41g 42" GO ON TO THE NEXT PAGE. 40 0 0 0 0 0 0 0 04 立B釭ed on the da伍in Figure 2, the % cure ofthccpoxy i=in made up of El and A2 at IIO min江closest to wltich of the following values? 兄70

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 12. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

B旺cd on the中丘;. Fi严2. which of the following correctly Ii心Al-A4 from lowest to出gh玉无cure when nactcd withEl for 50 m丘？ 43

Paper 81 · ACT December 2003 · Form 61E · Science Test

Ba,erl on the由口扫万gure 4,正a further trial with E2 血d A4 had been done at 40° C, the epoxy比劝,would m函likely havo比100% curod d吐g which of the fallowing timeintervals?

Paper 81 · ACT December 2003 · Form 61E · Science Test

A chemist h开0thes也,d that A4 will c立npletely cure 磁El Olld E2 if enough time is allowed. Do如da丘 inFigures 2 扛d 3 snpport his conclusion? 止ows中王E2 will cventliallybe 100% c=d. 土ows thatEl will eventually be 100无cmed. 如ws出a.tE2 will neverbe I00% cwed. shows山atEl will neverbe 100% cured. GO ON TO THE NEXT PAGE. 40 0 0 0 0 0 0 0 04 Passage IV A student smdied illominatioo us让g the followillg cquipmmE ． 如dcntical light bulbs(Bulbs A-F) • Fixture 1, ligh顷XI虹e for Bulbs A-E • Fixture 2,light丘tore for Bulb F • 2 identical paraffin blo吐s • A sb..t ofal皿血um foil having出C S血e length and Width asap玉ill block • A mctcrstick Light could pa,s throogh each paraffin bl吐and..ch block glowed°when light passed throogh_iL The al血血nm foil was pl比cd betw..o ·the 2 blocks. Toe li吐tfi江tures. light bulbs, blocks, foil, and the皿北rstick were arr扭ged 邸sbown边氏gurc 1. 吐四W 芒 top”ew Figure-I ln the following experiments, the bue of F江tur. 2 was always 0.200 m fromthealumin皿foil,立dLwu_thc distance from the base of F江血e 1 to the alumin山n foil. 砰eriment1 The student turned th巳 room lights off, lit Bulb A．旺d varied L until the 2 block, looked_cqually bright. This process was repeated us扛g Bulbs B-E. The results are shown in Table I. Table 1 Bulb lit (in addition to Bulb FJ Lloo(mk) ed w eq 比 u n all th y eblocks bright A 0.198 B 0.203 C 0.205 D 0.195 E 0.199 砰eriment 2 Toe procedure from Expcrimc_nt I was rcpc辽edming vario心combin,tions ofBulbs A-E. Toe n:soJts工c shown in Table 2. Table 2 Bulb,lit I L (m) when thcbloc匕 (ill ad山tionwBulbF) / _lo吐必勺ua!Jybright AandB A,B,C.andD A, B, C. D, and E

Paper 81 · ACT December 2003 · Form 61E · Science Test

Accor血g to区periment 2, as the number of lit b斗bs increased, L: The d过Unce bet吹en adjacent bulb, in万xrurc l w已the F. in已C缸cdonly. same for all of the bulbs.- G,· dccreas必only. Bulb F was always lit. J. 中缸ged,but with no general trend. ^．．1, 44 GO ON TO THE NEXT PAGE. �0 0 0 0 0 0 0 0 04 邓cb of_the foDo吐g best 坏plains why the立汕皿 urned offthe room lights? " To ensure that onfy the lightfrom Bulbs A-Filln· minated如2 paraffin bl心 • To ens匹C that Ji心t from outside the room il!III吐 natcd the 2paraffin bloc比unequally • To比ep the 2尽 araffinbloc比from castiug - ows, because,ha,Jows would m吐c the me立rscick harder to read To keep the 2 li乒t fixtures from ca.stiug sh述ows, because shadows would m吐e the meterstick harderto read oring Experiment 2, &oppose the srudeot rep!缸ed :ture I with a new fi江ure. The new fixture held ight bulbs, each bulb identical to Bulb F. W比mall •ulbs in the new fiatnrc were lit血d the paraffm 吐s loo比d匀Dlllly hrigh� Lwould probably have n closest to:

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 17. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 18. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 19. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Suppose that all of the light bulbs in F'lXtllre l were rep扛ed with a single bulb. B心ed on Experim,nt, I and 2,_if the 2 paraffin_b_locla loo比d equally bright wheo Fixture 2 -was 0.200 m from the alum.inum foil and L; 0.446 m, the brightness of the new light bulb W邸most lib:ly: l E －中e brightness ofoneofthe立如al bulbs. 6 I G. ¾ the brightness of叩e ofthe origmal bulbs. 5 IL 5 limesthe brightn立ofone ofthe ori臣nal bulbs. J, 6 times中e brighme.s, ofo皿oftbe ori臣叫bulbs.

Paper 81 · ACT December 2003 · Form 61E · Science Test

In氐pcrimcnt 2,环pposc the srudent had replaced Bulb F with am比h brighter light bnlb, Bulb G;Co匹 p红to L when Bulb Fw缸 us吐L wbcnBulb Gw压 nscd wooJdhave been: aod贮巳at巴when other comb血•tions oflightbulbs wcrc lit. 叩dy lit皿d rm认l口"hen otb口comb江丑沁n, of li吐t bulbs were lit. GO ON TO THE NEXT PAGE. 40 0 0 0 0 00 0 04 Passage V Student> studied how 4 met止一silv江(Ag), coppc, (Cu)，如o (Fc), and血c (Z沪eactwith止已元spective n;tra比salts: AgNO,. Cu(NO,J,. Fe(NO必and Zn(NO,)千 叩en a oitr也salt is di立Ived io w社立its中红血s into metalioa5 a:od正江ateioos: 。(NO,}z 一Cu让 ＋2NO, 乓erim,nt 1 A strip ofAg wasp虹ed in 1 molar(aunit ofcoocen­ tr迈叩） A纱IO, solu如it at zs•c,nd co皿比ted to a volt­ meter. A rtandard-hydrog,n electrode (a hydtogeo gu electrode)!'.:旺p缸"in acidsolutioo皿d co皿CC比dto如 voltmeter. The沁l皿ons WCrc coDllCC比d with a salt bridge (w氐ch allows io立to flow比tween solutio压）to comple,e 如ci,cuit（文C万gme l)． 万gure I Tbe meas立ed voltage（正volts, V) is the st血血记”duc­ tion paten血I, E0 . The比的口山c value of E0 , the more •"'ilY tbe metal io玉undergo md”“u,n (the g血of elec­ trans) ta fann a met,!. The prac吐urc w还repe&ted far each of tbe other me吐立d tb血respe立ive nitra比S斗t ,olutio立（S心Table!), Ecriment2 AstripofAgw...placed ill each of4血i:.rcot nitrate salt solution,. The studcuts observed whether metal p如ed (fotmed) on the s叮ace of the strip. The·procedure was repeated for血other 3 m己主(seeT止lc2). Table 2 Mc叫saip Solutioo I Ag Cu Fe Za AgNO, NR Agp!a四 Agph仁d Agpl社ed Cu(NO3)2 NR NR Cuplated Cnplated Fe(NO,>, NR NR NR Fcpla匕d z(NO山 邓 NR NR NR [Note:NR如otesthatno roa,:tion...., obscrv过． Eerimem3 Expcrim吐l 2 was repealed, b口l ins匕ad of using mtrate salt solutiollS, me巳l,trip, were placed u, eont..t with the士y （四血solved) salts江·d.丁立iviro立血立aod 。比orved for7中y..No reactioIJS occn六ed. Table l Me叫． E° 0 Ag 8 Fe Zn 80 34 “ 76 O ! T 3 立．Which ofthefoUowinristhe most n:asonab!e explana­ lion for why there were oo reactions observed in Experiment 3 ? me心10血vc rcac立d wi中my of如m叫salts 氐tcd. metals to have reacted wi中aoy of the metal salis 比仁d. 丑The salts werenot山s的Jved, so there were no free ion.s available tofon卫metals. J, The metal strips we,;,: uot coODectcd to a staod叫 hydrogen electrode, so no pla中g occum:d.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 22. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Based on the让formation in the p釭sage, which of the following most likely happens when Zo(NO山d氐 solves江water? ACT-"1E 46 GO ON TO THE NEXT PAGE. 40 0 0 0 0 0 0 0 04 丸When tin坛me"血d osing a心ndard hydrogcu elcc­ trade fellowing the s叩c procedure as w心used in Expenment1..VO虹gc is me...urcd thatj，比庐er than those me...ured for Fe and Zn, but lower tlian those measured forAg..dCu. W出中ofthe following is a plausib比valueforthe E" nf tin7 氐A stodent claimed that w比a metal strip is placed臼 the same metal's nitrate salt solution, no metal will formoathe m云工eofthemetal,trip. Do the resul压of Experiment 2 supportherclaim? whoo they wereplaced in the same工etal's ni比血 salt solution. when they were placed江the same meUl's ni丘记 salt soln丘on. when th匀were placed in归same metal's血rate salt sol血on. who• they were placed in the,皿1c metal's nitra比 ,alt,olution. .61E 47

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 24. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 25. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

A studeat claimed that Zn fons will more easily g皿 elec叩ns to form a metal than w山aay of the-other me吐tested.. Do the比sul比of丘pcrim..t I support bis claim? tested. than工y of the oth立 metals tes比d. th凸a.ny of如othcr mc叫5氐ted. m付可］C 仁,ted. 27, The E'oflead(Pb)丘-O.I3V.B己cd on the re过Its忒 E平criments I and 2.江one血p ofPb were pl止ed in an A心O, solution, andone strip ofPb were placed比 aZn(NO,h 』 pl solntion, wh吐wouldmost监己ly 0cc11r? GO ON TOTHE NEXT PAGE. 40 0 0 0 0 0 0 0 04 Passage VI 比 corn江止cs, pigmentation Is deter立iDcd by Genes O and B. These gcccs江con scp红也心romosomcs. All corns卫kcs have 2 copies ofeach gene. Ac叩叩丘s coloration depends on the a!J,l,s (forms of a gcnc) it car: ncs at thcsc genes. Corn sn立.. .. '立•PP="1°.or压胪己 black. all black. all orange, or albinotii:(1ackiog ic pi&• mcnt). GeDC Odetcrmincs wheth"orangepigmcnt.is pr<>­ duced. 00江d 0o com sa妇 ir od-“ange plgmem; oo c0!11 snake., do not Gene B 匕nniocs whether black pi严cnt is produ迅．BB and Bb core soak.es produce b吐 pigm血；bb CO!ll so吐sdo沁L A匕a吐立showed her srode皿s the rc,ults of3 studica to dcmonstr立e the rclatio正比p bctwccn ge心如 ( gc工tic m心叩）andp比notyp< (appeanncc) iD c叩sn止吐 St,.,lyl The归中ctp记senr.cd山ci:esult., of3 er”还in wbich both严血W"己BB atGeneB (••• Table I). Table I 三卢三：l1C •F =female; M =male. S也2 Toeteacbcr严~血dtheres业s of3 crosses in w血 both p叮ents were 00 at Gene O (soc Table 2). T心[c2 0:0:C 吓＝female; M = male. 4ri Sn,今3 The tC.1Cber produced Table 3 sho叶ng如results of 6 crosses. Some cells wue left b血so也c srudcu!Scould 严edict the omitted i血心平iou. Tablc3 ｀眢尸 •F= female; M =male.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 27. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

The infonnatioo pro vi七d iodicatcs山已albiootic coro 勾II.ave which ot山ctollo吐g gcootype,7

Paper 81 · ACT December 2003 · Form 61E · Science Test

With respect 10 Genes O md B. w压ch of the lollowini: a-asses wa.s identical to Cross 8 ? II. Cross 3 GO ON TO THE NEXT PAGE. 40 0 0 0 0 0 0 0 04 lO. W五cb of the follow正g crosses coald have been u沁d to produce the male p江entsioCross I ? l, What is the gouotypo althe忒扭ge匹db伍ckoff,pring 扫Cross 111 B, OoBb D, OOBb 49 3:z.Which of th乞followiog crosses woa!d molt in 50% offspring that were allorange and 50% offspring血t worealbinotic? IL oobb x OOBB

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 30. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 31. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 32. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Which ofthe follo吨g corre,;Uy shows the genotype cfthef玉叫cp釭en比Used坛Cross2? C, OoBb GO ON TO THE NEXT PAGE. 40 0 0 0 0 0 0 0 04 Passage VII lntroduc丘on The心de心(core) of皿atom coJll吐,sprata心(posi­ tivcly charged particles) and n,urrons {nneh叩cd ·p江五－ cles). Protons心d neu如氐江e also called nucleons. Nncleons江e attracted to each other hy stronr nucl,ar fo元es. Two modelsofthenucleus are discussed below. 九Liq叫DmpM吐／ SoDlCnuclearpro严~~ r~emble山e.collective prop­ crtics ofthemolecules ln adrop ofpure water. • The stability of a nuclens ;, related to its shape. A nuclcu, is most stable (unr立ctivc) w比n spherical; drop-s垣pcd nuclei arc more出:ely to undergofis,ion (split apart) than spherical nuclei. • The m还and volume of a nucleus arc proportional to 如number of nucleons ii> the noel已IS, • The com如血g of 2 n皿压rcsemb比如com兰g of 2 dr0ps ofwat.or. • Co正sfons of bigh-ene屯y nucleons wi山山e nuclei of ccrtain d凹比卫”Cause中enuclei to undergo丘乌ion,j心t as projectile, di沁于t drop, ofwat立 The Slwl Model A nucleus contains dis血ct bands of enc屯y called energy shel比Its nucleons arc rcsrric仁d to these >hells. Each nucle立con区血many such shells, but not all血Es contain noclco芯．Each立ell ;, identified by a n立nber. Table 1 conta丘, the cap正ties ofthe丘文3土心． T吐,le 1 M叮imum number of: 了！了1 正 了1了 • When every止ell is either empty or con已江Sits ID勾j­ mum皿mber of protons orncntrons, annclcus is magic. For example, the nucleus with a total of 20 protons iJld 19 neutrons bas a magic心mber of protons. because the only shells吐con呻胚yprotons (Shells !, 2,正d 3) con _ t立itbc让maximum numbcrs of proto心．Magic noclei arc generally more s也blc中扭other noclei The nucleus with 20 protons and 20 Deutron, is doubly mag;c (ma乒C切both protons •od oeu江oos). Do吵ly ma臣c nuclei arc the most＄组ble nuclei正dares比pod 出sphe=. Acr..', 50 • Low七nern nenlrons willp3SS thronCh lhe nucld of IIWlyclcme心Wl出out比ing皿peded．妇节liesthat th· Ducleons insidc • Ducleu, wilI not in比”e wi中 c_ach o山cr印di. con中1cnt wi中nucleons being江 shells. 丸According to the LiquidDrop M必吐I皿如is恤ast 比ely to underiO fission under which ofthe following conditions? 江．Wbenthe nucleta丘sb.ped like aSphe~ 3S. According to the Shell Model, if a n匹ieus con压n$

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 34. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 35. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

比Ye可massive s江rs,..e屯y is produced when a helium nucleus and • be可Ilium nucleus combine to form a e的on nucleu,. According to the Liquid Drop Model, th• formation of a c扛bon nucleus can be UK心ed to the: 咒combinini of 2 liquid如ps. f· 五ssionof2liquid＆窊

Paper 81 · ACT December 2003 · Form 61E · Science Test

The 2 theories agree that the most stable nuclei江e those that GO ON TO THE NEXT PAGE. 40 0 0 0 0 0 0 0 04

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 38. Refer to the source image.

Paper 81 · ACT December 2003 · Form 61E · Science Test

..0 3B 37 36 35 34 33 31-32 30 29 2B 句 26 24-25 23 22 20-21 19 18 17 15-16 14 12·13 10一11 08-09 07 06 05 04 03 02 01 00 ST ei estl心4 e 39-40 蕊 3 箕 35 34 33 32 妇1 2 叮竺 26 24竺 22竺 20-'11 18-19 11 15-16 14 13 11-12 10 09 08 07 妇6 04 ＿ 03 02 01 00 勹－牛＇ 匕邑· Sc叫· score 36 35 34 33 32 31 30 29 28 27 26 五 24 23 22 21 2D 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 微信号：loviact

Paper 81 · ACT December 2003 · Form 61E · Science Test

Source question 40. Refer to the source image.