A2 Unit5 Nuclear 09 More About Decay Modes-4
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Transcript of A2 Unit5 Nuclear 09 More About Decay Modes-4
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More About Decay
Modes
Nuclear Physics Lesson 9
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HomeworkHomework
Revise for the skills test.Revise for the skills test.
HWK days:HWK days:
Tues Wk 1 Period 4Tues Wk 1 Period 4
on Wk ! Period !on Wk ! Period !
Thurs Wk ! Period 4Thurs Wk ! Period 4
Nuclear Physics Test " so#e ti#e $efore halfNuclear Physics Test " so#e ti#e $efore half
ter#.ter#.
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Learning ObjectivesLearning Objectives
To inter%ret the N"& chart for radioactiveTo inter%ret the N"& chart for radioactive
isoto%es.isoto%es.
To kno' ho'To kno' ho' (()) **""andand **++ decay aredecay arere%resented on the N"& chart.re%resented on the N"& chart.
To a%%ly this to a radioactivity series.To a%%ly this to a radioactivity series.
To kno' ho' to re%resent nuclear ener,yTo kno' ho' to re%resent nuclear ener,y
levels.levels.
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The N-Z ra!hThe N-Z ra!h
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N-Z "#otN-Z "#ot
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Notes on the N-Z "#otNotes on the N-Z "#ot
-or li,ht ele#ents & / !0) N is rou,hly-or li,ht ele#ents & / !0) N is rou,hly
e2ual to & for sta$le %rotons) i.e. e2uale2ual to & for sta$le %rotons) i.e. e2ual
nu#$ers of %rotons and neutrons.nu#$ers of %rotons and neutrons.
3s the ele#ents ,et heavier) #ore3s the ele#ents ,et heavier) #ore
neutrons are needed for the stron, forceneutrons are needed for the stron, force
to overco#e the oulo#$ re%ulsion 506to overco#e the oulo#$ re%ulsion 506#ore N than & for the heaviest ele#ents.#ore N than & for the heaviest ele#ents.
so the line of sta$ility $ends u%'ards.so the line of sta$ility $ends u%'ards.
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Notes on the N-Z "#otNotes on the N-Z "#ot
((e#itters & 7 80e#itters & 7 80
**""
e#itters a$ove the sta$ility linee#itters a$ove the sta$ility line
**++e#itters $elo' the sta$ility linee#itters $elo' the sta$ility line
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Decays $e!resented onDecays $e!resented on
N-Z "#otN-Z "#otou need to kno' ho' to sho'ou need to kno' ho' to sho' (()) **""andand **++..
TH; N< W3TH; N< W3R>?N@AR>?N@A
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%&ercise%&ercise
@ra' the N"& ,ra%h for kno'n isoto%es.@ra' the N"& ,ra%h for kno'n isoto%es.
ndicate the line of sta$ility and descri$endicate the line of sta$ility and descri$e
ho' and 'hy it chan,es as & is increased.ho' and 'hy it chan,es as & is increased.
ndicate 'here thendicate 'here the (()) **""andand **++ e#itterse#itters
'ill a%%ear on the ,ra%h.'ill a%%ear on the ,ra%h. =B%lain 'hy they a%%ear in these re,ions=B%lain 'hy they a%%ear in these re,ions
of the ,ra%h.of the ,ra%h.
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Nuc#ear %nergy Leve#sNuc#ear %nergy Leve#s
3fter a nucleus has e#itted an al%ha or a3fter a nucleus has e#itted an al%ha or a
$eta %article) the dau,hter nucleus #ay$eta %article) the dau,hter nucleus #ay
$e in an eBcited state.$e in an eBcited state.
This 'ill cause it to e#it a %hoton as itThis 'ill cause it to e#it a %hoton as it
de"eBcites.de"eBcites.
t 'orks Cust like electrons #akin,t 'orks Cust like electrons #akin,transitions $et'een ato#ic ener,y levelstransitions $et'een ato#ic ener,y levels
DD but it takes !#ace in the nuc#eusbut it takes !#ace in the nuc#eus
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'a#cu#ate the !hoton'a#cu#ate the !hoton
wave#ength(wave#ength(
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%&ercise%&ercise
@escri$e the t'o 'ays@escri$e the t'o 'ays
that a 0.EF eG %hotonthat a 0.EF eG %hoton
can $e e#ittedcan $e e#itted
=B%lain ho' the $eta=B%lain ho' the $eta
decay of ,"!I candecay of ,"!I can
result in either 1 or !result in either 1 or !
%hotons $ein, e#itted.%hotons $ein, e#itted.
alculate the F %hotonalculate the F %hoton
fre2uencies %ossi$le.fre2uencies %ossi$le.
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A )igger "ictureA )igger "icture
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*ummary*ummary
3 ,ra%h of neutron nu#$er a,ainst %roton3 ,ra%h of neutron nu#$er a,ainst %roton
nu#$er sho's that there are #ore neutronsnu#$er sho's that there are #ore neutrons
in lar,er nuclei.in lar,er nuclei.
This is needed to ensure sta$ility of theThis is needed to ensure sta$ility of the
nuclei.nuclei.
=Bcited nuclei ,ive oJ ,a##a rays after=Bcited nuclei ,ive oJ ,a##a rays after
e#ittin, an al%ha %article or a $eta %article.e#ittin, an al%ha %article or a $eta %article.
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$eca!$eca!
Ho' are ,a##a rays e#itted $y theHo' are ,a##a rays e#itted $y the
nucleusnucleus