modul f t 5 keradioaktifan 5 radioactivity · based on the graph above, determine the half-life of...
TRANSCRIPT
© Nilam Publication Sdn. Bhd. 188
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
KeradioaktifanRadioactivity5
• Menghuraikankomposisinukleusatomdalamsebutanprotondanneutron.Describe the composition of the nucleus of an atom in terms of protons and neutrons.
• Mendefinisikannomborproton(Z)dannombornukleon(A)./Define proton number (Z) and nucleon number (A).• Menerangkanistilahnuklid./Explain the term nuclide.• Menggunakannotasinuklid
A
ZX/Use the nuclide notation
A
ZX
• Mendefinisikanistilahisotop./Define the term isotope.
5.1 Memahami nukleus atom / Understanding the nucleus of an atom
• Menyatakanmaknaradioaktif./State what radioactivity is.• Menamakanpengesansinaranradioaktif./Name common detectors for radioactive emissions.• Membeza-bandingkan3jenissinaranradioaktifdariaspekkesemulajadiannya.
Compare the three kinds of radioactive emissions in terms of their nature.• Menerangkanreputanradioaktif./Explain what radioactive decay is.• Menggunakanpersamaanuntukmenggambarkanperubahankomposisinukluesapabilazarahdipancarkan.
Use equations to represent changes in the composition of the nucleus when particles are emitted.• Menerangkansetengahhayat./Explain half-life.• Menentukansetengahhayatdarisuatugrafreputan./Determine half-life from a decay curve.• Menyelesaikanmasalahberkaitansetengahhayat./Solve problems involving half-life.
5.2 Menganalisis reputan radioaktif / Analysing radioactive decay
• Mendefinisikanradioisotop./Define radioisotopes.• Menamakancontohradioisotop./Name examples of radioisotopes.• Menghuraikanaplikasiradioisotop./Describe applications of radioisotopes.
5.3 Memahami kegunaan radioisotop / Understanding the uses of radioisotopes
• Mendefinisikanunitjisimatom(u.j.a.)./Define atomic mass unit (a.m.u.).• Menghuraikanpelakurannuklear./Describe nuclear fission.• Memberikancontohpelakurannuklear./Give examples of nuclear fission.• Menghuraikantindakbalasberantai./Describe chain reactions.• Menghuraikanpelakurannuklear./Describe nuclear fusion.• Memberikancontohpelakurannuklear./Give examples of nuclear fusion.• Menghubungkaitkanpelepasantenagatindakbalasnukleardenganperubahanjisimberdasarkanpersamaan• E=mc2./Relate the release of energy in a nuclear reaction with change of mass according to the equation E = mc2.• Menghuraikanpenjanaanelektrikdaripelakurannuklear./Describe the generation of electricity from nuclear fission.• Memberialasankuatuntukpenggunaanpelakurannukleardalampenjanaanelektrik.
Justify the use of nuclear fission in the generation of electricity.• Menyelesaikanmasalahberkaitantenaganuklear./Solve problems involving nuclear energy.
5.4 Memahami tenaga nuklear / Understanding nuclear energy
05-Physic F5 2015 (FSY5p).indd 188 10/15/15 3:14 PM
© Nilam Publication Sdn. Bhd.189
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
1 Jirimterdiridaripadazarahkecilyangdinamakan atom .
Matter is made up of very small particles called atoms .
2 Setiapatommempunyaiterasyangsangatkecildansangattumpatyangdinamakan nukleus dan
elektron mengelilinginya.
Each atom has a very small and very dense core called nucleus and electrons move in orbits around the nucleus.
3 Kebanyakan jisim atomterdapatdidalamnukleus.
Most of the mass of atom is contained in the nucleus.
4 Nukleusterdiridaripada proton danneutron.
A nucleus consists of a number of protons and neutrons.
5 Protondanneutronjugadikenalisebagai nukleon .
Protons and neutrons also known as nucleons .
6 Protonbercas positif .
A proton has a positive charge.
7 Neutronialahzarahyang tidakbercas yangmempunyai jisimyangsama sepertiproton.
A neutron is an uncharged particle of the same mass as the proton.
TerminologiTerminology
PeneranganExplanation
Nomborproton,ZProton number, Z
Didefinisikansebagai bilanganprotondalamnukleus .
Is defined as the number of protons in a nucleus .
Nombornukleon,ANucleon number, A
Jumlahbilanganprotondanneutrondalamnukleus .
Is the total number of protons and neutrons in a nucleus .
NuklidNuclide
Nuklid ialah struktur atom tertentu yang mempunyai nombor nukleon dan nombor protontersendiri.A nuclide is an atom of a particular structure, having its own particular nucleon number and proton number.A
ZX
IsotopIsotope
Isotopialahstrukturatomyangmempunyainombor protonyangsama tetapi
nombor nukleon yangberbeza.
Isotopes are atoms which have the same proton number but different nucleon numbers.
• Menghuraikankesanburukbahanradioaktif./Describe the negative effects of radioactive substances.• Menghuraikanlangkah-langkahkeselamatanyangdiperlukandalampengendalianbahanradioaktif.
Describe safety precautions needed in the handling of radioactive substances.• Menghuraikanpengurusanbuanganradioaktif./Describe the management of radioactive waste.
5.5 Kesedaran kepentingan pengurusan baik terhadap bahan radioaktifRealising the importance of proper management of radioactive substances
Memahami Nukleus Bagi Atom Understanding the Nucleus of An Atom
5.1
05-Physic F5 2015 (FSY5p).indd 189 10/15/15 3:14 PM
© Nilam Publication Sdn. Bhd. 190
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
1 ContohbaginuklidX/Example of nuclide X.(a) 40
10X(i) NomborprotonbagiXialah 10 .
The proton number of X is 10 .
(ii) NombornukleonbagiXialah 40 .
The nucleon number of X is 40 .
(iii) BilanganneutrondalamnukleusXialah 40–10=30 .
The number of neutrons in X nucleus is 40 – 10 = 30 .
(b) 12
6C(i) NomborprotonbagiatomCialah 6 .
The proton number of C is 6 .
(ii) NombornukleonbagiatomCialah 12 .
The nucleon number of C is 12 .
(iii) BilanganneutrondalamatomCialah 6 .
The number of neutrons in C nucleus is 6 .
(c) 84
36Kr(i) Berapakahbilanganneutrondalamnukleusatomkripton?
What is the number of neutrons in the nucleus of krypton?
84–36=48
(ii) Nukleusbagikripton lainmempunyaiduaneutronyangberlebihan.TuliskansimboldalambentukA
ZXbagiatomkriptonini. Another nuclide of krypton has two extra neutrons. Write the nuclide notation for this nuclide.
Bilanganneutron=48+2=50
Nomborprotonkekalsamadengan36memandangkanianyaelemenyangsama
Nombornukleon=36+50=86
Simbolbagiisotopkriptoniniialah86
36Kr Number of neutrons = 48 + 2 = 50
The proton number remains at 36 since it is the same element
Nucleon number = 36 + 50 = 86
Symbol for this isotope of krypton is
86
36Kr
2 Isotopsuatuunsurmempunyaibilangan proton danbilangan elektron yangsama.
Isotopes of an element contain the same number of protons and the same number of electrons .
3 Kripton-84 dan Kripton-86 dikenali sebagai isotop bagi kripton. Jadi, isotop mempunyai ciri-ciri
kimiayangsama keranatindakbalaskimiamelibatkanelektrondalamatomtersebut.
Krypton-84 and Krypton-86 are known as isotopes of krypton. So, isotopes have the same chemical properties because chemical reactions involve the electrons in an atom.
4 Seterusnya,isotopmempunyaiciri-ciri fizikalyangberbeza kerana jisimnya berbeza.
Therefore, isotopes have different physical properties because their mass is different.
05-Physic F5 2015 (FSY5p).indd 190 10/15/15 3:14 PM
© Nilam Publication Sdn. Bhd.191
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
TerminologiTerminology
PeneranganExplanation
KeradioaktifanRadioactivity
Keradioaktifanadalah penyusutansecaraspontan nukleusyang tidakstabil
menjadinukleusyanglebih stabil denganmemancarkan zarahbertenaga
(sinaranradioaktif)ataufoton.
Radioactivity is the spontaneous disintegration of an unstable nucleus into a
more stable nucleus accompanied by the emission of energetic particles (radioactive rays) or
photons.
Atau/Or
Adalahreputansecara spontan danrawaksatunukleusyangtidakstabilkepadanukleus
yangstabildenganmemancarkanzarah alfa , beta atausinar gama .
Is the spontaneous and random decay of an unstable nucleus into a more stable nucleus with emissions
of alpha , beta or gamma radiation.
ProsesspontanSpontaneous process
Merujukkepadaprosesyangtidakdipengaruhiolehfaktorluarseperti suhu ,
tekanan , medanelektrik dan medanmagnet .
Refers to a process that is not triggered by any external factors such as temperature ,
pressure , electric fields or magnetic fields .
SinaranelektromagnetElectromagnetic radiation
Ialahgelombangelektromagnetyangterdiridaripadakumpulantenagakecilyangdipanggil
foton .
Is electromagnetic waves that consist of small energy packets called photons .
PancaranradioaktifRadioactive emission
Jugadikenalisebagai zarahyangbertenaga atau foton ,sepertizarahalfa,
zarahbetadansinargama.
Also known as energetic particles or photons , such as alpha particle, beta particle and
gamma ray.
ReputanradioaktifataupenyusutanradioaktifRadioactive decay or radioactive disintegration
Prosesyangmananukleusyangtidakstabilberubahkepadanukleusyanglebihstabildenganmemancarkansinarradioaktif.Is the process in which an unstable nucleus changes into a more stable nucleus by emitting radiation.
Menganalisis Reputan Radioaktif Analysing Radioactive Decay
5.2
05-Physic F5 2015 (FSY5p).indd 191 10/15/15 3:14 PM
© Nilam Publication Sdn. Bhd. 192
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
BandingkansifatsemulajaditigajenissinaranradioaktifCompare the three kinds of radioactive emissions in terms of their nature
SinaranradioaktifRadioactive emissions
Zarahalfa,αAlpha particle, α
Zarahbeta,βBeta particle, β
Sinargama,Gamma ray, γ
SemulajadiNature
Nukleushelium/Helium nuclei
4
2He
Elektronberhalajutinggi Electrons with high velocity
0
–1e
GelombangelektromagnetElectromagnetic Wave
JisimMass
Jisimnyajauhlebihbesar daripadajisim
zarahbeta
Its mass is much bigger than that of a beta particle
Jisimnyajauhlebih kecil daripadajisimzarahalfa
Its mass is much smaller than that of an alpha particle
0(zero)
CasCharge
Cas positif
Positive charge
Cas negatif
Negative charge Neutral
KuasapengionanIonising power
Tinggi/High Sederhana/Medium Rendah/Low
KuasapenembusanPenetrating power
Rendah/Low SederhanaMedium
Sangattinggi/Very high
DiberhentikanolehStopped by
sehelaikertas
A sheet of paper
Beberapa mmaluminium
A few mm of aluminium
Beberapa cmplumbum
A few cm of lead
LajuSpeed
Lajunya lebihrendah
daripadalajuzarahbetaLower than the speed of a
beta particle
Lajuyang sangat
tinggi yangmencapai90%lajucahaya
Very high speed which is up to 90% of the speed of light
Bergerakdengan laju cahaya dalamvakum
Move at the speed of light in a vacuum
Ciri-ciriSinaranRadioaktifCharacteristics of Radioactive Emissions
KesanpengionanIonising effect
KuasapenembusanPenetration power
Interaksidenganmedanelektrikdanmedanmagnet
Interaction with electrical field and magnetic field
Pengionanatommenghasilkanion-ion
positif danion-ion negatifThe ionisation of an atom produces
positive ion and negative ionsAlfa/Alpha
(a) Tumpat/Dense
(b) Runutyang lurus
Straight tracks
(a) Sinarradioaktifyangmempunyaikuasapengionanyangpalingtinggiakanmempunyaikesanpenembusanyang
palingrendah .Radiation which has the strongest
ionising power will have the
lowest penetration effect.
(a) Pesonganzarahbeta lebih
besar darizarahalfa
keranajisimbeta lebihkecil darijisimalfa.The deflection of beta particles is
larger than alpha particles
becuase beta particles have a
smaller mass than that of alpha particles.
05-Physic F5 2015 (FSY5p).indd 192 10/15/15 3:14 PM
© Nilam Publication Sdn. Bhd.193
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
(c) Zarahalfayangmempunyaijisimdanmomentumyangbesarmaka
ia tidakmudahterpesong Alpha particle has a large mass and momentum so it is
not easily deflected
(d) Zarahalfamenghasilkanbanyakpasanganiondalammedium.Alpha particles produce the most ion pairs in a medium.
ZarahalfaAlpha particle
Beta
(a) Zarahbetayangsangatlajumempunyairunutyang
nipisdanlurus The faster beta particle has
thin straight tracks
(b) Zarahbetayanglebihperlahanmempunyairunutyang
pendek dan tebal melengkungkearahrawak.The slower beta particles have
short and thick tracks which curve in random directions.
ZarahbetaBeta particle
Gama/GammaSinarangamatidakmenghasilkanrunutyangtebal,jelasdan
berterusan keranakuasapengionanyangpalingrendah.The gamma rays do not produce thick, clear
and continuous tracks due to
their low ionising power.
SinarangamaGamma ray
(b) Sinaranradioaktifakankehilangansebahagian
tenaganya setiapkalipasanganiondihasilkan.The radioactive emission loses some of
its energy each time an ion pair is produced.
(c) Zarahalfakehilangan tenaga sangatcepatsemasabergerakmelaluimedium.
Alpha particles lose energy very quickly as they move through a medium.
(d) Olehitu, zarahalfa mempunyaikuasapenembusan
yang palingrendah .
So alpha particles have the
lowest penetrating power.
zarahαα-particles
zarahββ-particles
sinarγγ-rays
SehelaikertasA sheet of paper
Aluminium(beberapa
mm)Aluminium(A few mm)
Plumbum(beberapa
cm)Lead
(A few cm)
(b) Sinarangama tidak
terpesong keranaiatidakmembawacas.
Gamma rays are not deflected
because they do not carry any charge.
MedanelektrikElectric field
zarah-ββ-particles
zarah-αα-particlessinar-γγ-raysRadioactive source
Sumberradioaktif
MedanmagnetMagnetic field
Zarahalfa dan zarahbeta
akan terpesong apabilamereka
melepasimedanmagnettetapi
sinarangama tidakdipesongkan .
Alpha particles and beta
particles are deflected when they
pass through a magnetic field while gamma
rays are not deflected .
MedanmagnetkedalamkertasMagnetic field into the paper
Petunjuk/Key:
α,β,γα,β,γ
αα
ββ
γγ
05-Physic F5 2015 (FSY5p).indd 193 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 194
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
Reputanradioaktif:Radioactive decay:
1 Apabila nukleus radioaktif mereput, nukleus akan pecah dan memancarkan zarahalfa atauzarahbeta dan tenaga .Iamenghasilkan atombaru bagiunsuryangberbeza.
When a radioactive nucleus decays, its nucleus break up and emits an alpha or beta particle and energy . It forms a new atom of a different element.
2 Selepasreputanradioaktif,bilangan proton dan neutron dalamnukleusakanberubah.
After radioactive decay, the number of protons and neutrons in the nuclei will change.
(a) Reputanalfa/Alpha decay Persamaanbagireputanalfa:/The general equation of alpha decay is:
A
ZX A – 4
Z – 2Y + 4
2 He + EnergyA
ZX A–4
Z–2Y+4
2He+TenagaParentnuclide
NukleusInduk
Daughternuclide
Nukleusanak
Alphaparticle
Zarahalfa
• Dalamreputanalfa,nukleusyangtidakstabilmemancarkan zarahalfa .
In alpha decay, the unstable parent nuclide emits an alpha particle.
• Nombor proton Zakandikurangkansebanyak2dannombor neutron ,Adikurangkansebanyak4padanukleousanak.
The daughter nuclide, its proton Z reduced by 2 and the neutron nombor, A its reduced by 4.
Contoh / Example
Isikantempatkosongdenganjawapanyangbetul.Fill in the blanks with the correct answers.
(a)238
92U Th+4
2He (b)210
84Po 206
82Pb+Penyelesaian/ Solution
(a)234
90Th (b)4
2He
(b) ReputanBeta/Beta Decay Persamaanbagireputanbeta:/The general equation of beta decay is:
A
ZX A
Z+1Y+0
–1e+Tenaga
Nukleusinduk
Nukleusanak
Zarahbeta
A
ZX A
Z + 1Y + 0
–1e + EnergyParentnuclide
Daughternuclide
Betaparticle
Apabila nukleusmereput denganmemancarkan zarah beta , maka nombor proton Z
ditambahsebanyak1tetapinombor neutron ,A,tidakberubah.
When a nuclide decays by emitting a beta particle, its proton number Z increases by 1 and its neutron number, A does not change.
Contoh / Example
Isikantempatkosongdenganjawapanyangbetul.Fill in the blanks with the correct answers.
(a)90
38Sr Y+0
–1e
05-Physic F5 2015 (FSY5p).indd 194 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.195
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
(b)40
19K 40
20Ca+Penyelesaian/Solution
(a)90
39Y (b)
0
–1e
(c) ReputanGama/Gamma Decay (i) Sinaranelektromagnetyangberfrekuensitinggidibebaskandaripadanukleusyangtelahmereput
dipanggilsinar gama .
High frequency electromagnetic radiation coming from a decaying nucleus is called gamma radiation. Persamaanreputangama: The general equation of gamma decay is:
A
ZX AZX+γTenagatinggi
Tenagarendah
A
ZX A
ZX + γHigher energy
Lower energy
(ii) Dalamreputangama,nukleusdalamkeadaanteruja(parastenagayanglebihtinggi)memancarkansinarγuntukmenukarkepadaparastenagayanglebihrendah.
In gamma decay, a nucleus in an excited state (higher energy state) emits a γ-ray to change to a lower energy state. (iii) Sinar gama dipancarkan sama ada bersama dengan zarah alfa atau beta dalam masa yang
sama. Gamma rays are emitted at the same time together with either alpha or beta particles.
(iv) Tiadaperubahandalamnombor nukleon dannombor proton .
There is no change in the nucleon number and proton number.
Contoh / Example
Isikantempatkosongdenganjawapanyangbetul.Fill in the blanks with the correct answers.
(a)60
27Co Co+γ
(b)83Bi
214
84Po+0 e+γ
(c) 232
90Th 208
82Pb+4
2He+0
–1e+γ Berapakahzarahalfadanzarahbetayangdipancarkanapabila
232
90Thmereputmenjadi208
82Pb? How many alpha particles and beta particles are emitted when
232
90 Th decays into 208
82 Pb ?
Penyelesaian/ Solution
(a) A=60 Z=27
(b)214
83Bi,0
–1e
(c)232
90Th→208
82Pb+64
2He+40
–1e+γ
05-Physic F5 2015 (FSY5p).indd 195 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 196
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
SiriReputanA decay seriesKadangkalanukleusanak(nukleusbaru)bagiunsurradioaktif,masihlagitidakstabil.Ianyaakanmereputkepada
nukleuslainyangjugatidakstabil.Prosesiniberterusandandikenalisebagai siripereputanradioaktif
sehinggamenghasilkan nukleusyangstabil .Sometimes the daughter nuclide of a radioactive nucleus is still unstable. It will eventually decay into another nuclide which is also
unstable. This process continues and it is called a radioactive decay series until a stable nuclide is produced.
238
92U 234
90Th 234
91Pa 226
88Ra 230
90U 234
92Uα ββ α α
Contoh / Example
238
92U 234
90Th 23491Pa 234
92U 226
88Ra
1 RajahdiatasmenunjukkansebahagiandarireputanradioaktifUranium-238.The diagram above shows part of an Uranium-238 radioactive decay series.(i) UraniumU-238mereputkepadathoriumTh-234.Tulissatupersamaanuntukmenunjukkanproses
reputan.Uranium-238 decays to Thorium-234. Write an equation to show the decaying process.
(ii) TerangkanperubahandalamnukleusUranium-238semasaprosesmereput.Explain the changes in the nucleus of Uranium-238 during the decaying process.
(iii) Tentukanbilanganzarahalfadanzarahbetayangdihasilkanolehsiripereputanradioaktif.Determine the number of alpha particles and beta particles produced by the radioactive decay series.
Penyelesaian/ Solution
(i)238
92 U 234
90 Th+4
2He (ii) Semasareputanalfa,nomborprotonakanberkurangsebanyak2dannomborneutronjugaakan berkurangsebanyak2ataunombornukleonberkurangsebanyak4. During the alpha decay, the number of protons decreases by 2 and the number of neutrons also decreases by 2, that is, the nucleon number decreases by 4. (iii) 3zarahalfadan2zarahbeta. 3 alpha particles and 2 beta particles.
2 Rajahmenunjukkansirireputanradioaktif.The diagram shows part of a radioactive decay series.
Nombornukleon,ANucleon number (A)
Nomborproton,ZProton number (Z)
22287 88 89 90 91 92
226
230
234
238
III
II
I
NamakanzarahatausinaranradioaktifyangdipancarkandalambahagianI,IIdanIII.Name the particles or radiations emitted at parts I, II and III.
05-Physic F5 2015 (FSY5p).indd 196 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.197
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
Penyelesaian/ Solution I :Zarahalfa/Alpha particle II :Zarahbeta/Beta particle III :Zarahbeta/Beta particle
SetengahhayatHalf-life
Setengahhayatbagiunsurradioaktifialah masayangdiambil untukatomyangtidakstabilmereputmenjadi
setengahdaripadanilaiasalatausetengahhayat ialahmasayangdiambiluntuk keaktifannya
berkurangmenjadi setengah daripadanilaiasalnya.
The half-life of a radioactive element is the time taken for the unstable atoms to decay to half of its original value or,
half-life is the time taken for its activity to fall to half of its original value.
Contoh / Example
1 Setengahhayatunsurradioaktifyangberjisim40gialah2jam.Tentukanjisimunsurradioaktifyangsudahmereputselepas6jam.The half-life of a radioactive material of mass 40 g is 2 hours. Determine the mass of the radioactive material that has decayed after 6 hours.
PenyelesaianSolution
40g 20g 10g 5g
Selepas6jam,35gsudahmereputSo after 6 hours, 35 g has decayed
2 jam / hours 2 jam / hours 2 jam / hours
2 Setengah hayat untuk Natrium-24 ialah 16 jam. Berapakah masa yang diambil untuk Natrium-24 untukmenyusutdari0.64gkepada0.04g?The half-life of Sodium-24 is 16 hours. What is the time taken for Sodium-24 to shrink from 0.64 g to 0.04 g?
PenyelesaianSolution
0.64g 0.32g 0.16g 0.08g 0.04g
Masayangdiambil=16jam×4=64jamTime taken = 16 hours × 4 = 64 hours
16 jam / hours 16 jam / hours 16 jam / hours 16 jam / hours
05-Physic F5 2015 (FSY5p).indd 197 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 198
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
3 SetengahhayatuntukBa-143ialah12saat.BerapakahmasayangdiambiluntukaktivitiBa-143berkurang
kepada1
16daripadanilaiasalnya?/The half-life of Ba-143 is 12 seconds. How long will it take for the activity of a Ba-
143 sample to be reduced to 116 of its original value?
[Perhatian:"Unit"disinimewakiliunitaktiviti./Note : "Unit" here is used to represent the unit of activity.]
Penyelesaian/ Solution
1unit 12
unit 14
unit 18
unit 116
unit
Masauntukberkurangkepada116
unit=12s×4=48s
The time taken to be reduced to 116 unit = 12 s × 4 = 48 s
12 s 12 s 12 s 12 s
4 Rajahmenunjukkangrafaktivitilawanmasauntuksuatubahanradioaktif.The diagram shows the graph of activity against time for a radioactive material.
Aktiviti/bilanganminit–1
Activity / counts minute–1
120
60
0 20 70Masa/minitTime / minutes
Berdasarkangrafdiatas,tentukansetengahhayatbagiunsurradioaktiftersebut.Based on the graph above, determine the half-life of the radioactive material.
Penyelesaian/ Solution
Masayangdiambilolehbahanradioaktifuntukmenjadisetengahdariaktiviti120bilanganperminitkepada60 bilanganperminit =70minit–20minit=50minit The time taken for the radioactive material to become half of its activity from 120 counts per minute to 60 counts per minute = 70 minutes – 20 minutes = 50 minutes
Olehitu,setengahhayat,T12=50minit
Therefore the half-life, T12 = 50 minutes
5 Pelajarmenjalankansatueksperimenuntukmengetahuihubunganantarakadarreputandanmasa. Keputusaneksperimenmenunjukkangrafaktivitilawanmasadalamrajahdibawah.
A student carries out an experiment to find out the relationship between decay rate and time. The result of the experiment is shown in the graph of activity against time at the diagram below.
100
200
300
400
500
10
Aktiviti/bilanganperminitActivity / counts per minute
Masa/jamTime/hour3 42 5
KBAT
05-Physic F5 2015 (FSY5p).indd 198 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.199
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
(a) AktivitiNobolehdidapatkandaripintasanaktiviti.Tunjukkanpadagraf,bagaimanauntukmenentukanN
o
dannyatakannilaitersebutdidalamruangdibawah.Activity N
o can be obtained from activity intercept. Show on the graph how you would determine N
o and state the value
at the space given below.
No=
(b) Nyatakanhubunganantaraaktivitidanmasa./State the relationship between activity and time.(c) Darigraf,/From the graph,
(i) tentukan setengah hayat, T12 bagi unsur radioaktif. Tunjukkan di dalam graf bagaimana untuk
menentukanT12.
determine the half-life, T12 , of the radioactive element. Show on the graph how you determine T1
2.
(ii) carinilaiaktivitiyangmasihtinggalselepas4jam. find the value of the activity left after 4 hours.
(d) Nyatakandualangkahberjaga-jagayangperludiambilsemasamengendalikanunsurradioaktif.State two precautions to be taken when handling radioactive elements.
Penyelesaian/ Solution
(a) Grafmenunjukkan/ As shown on the graph: N
0=500bilanganperminit/ N
0 = 500 counts per minute
(b) Aktivitiberkurangsecaraeksponendenganmasaataukeaktifanberkurangdenganmasa,t Activity decreases exponentially with time or the activity decreases with time, t
(c) (i) GrafmenunjukkanT12=1.5jam/ As shown on the graph, T1
2 = 1.5 hour
(ii) Grafmenunjukkan,/ As shown on the graph, Bakiaktiviti=90bilanganperminit The activity left = 90 counts per minute (d) 1. Sumberradioaktifharusdikendalikandengansistemkawalanrobotdisebalikbesi,konkrit,plumbumdan panelgelasplumbumyangtebal. Radioactive sources should be handled with robotic control systems behind steel, concrete, lead or thick lead glass
panels. 2. Lencanaradioaktifyangmengandungifilemfotografiperludipakaiuntukmemantaudossinaranyang
diterima. Radiation badges containing photographic film should be worn to monitor exposure to radiation.
TerminologiTerminology
PeneranganExplanation
RadioisotopRadioisotope
Radioisotopadalahisotopyang tidakstabil yangmananukleusyangtidakstabilnya
mereputdanmemancarkan sinarradioaktif sepertiα,β,γ.Radioisotopes are unstable isotopes with unstable nuclei which decay and emit radioactive emissions
like α, β, and γ.
Memahami Kegunaan Radioisotop Understanding the Uses of Radioisotopes
5.3
05-Physic F5 2015 (FSY5p).indd 199 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 200
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
Aplikasiradioisotop/Applications of Radioisotopes
BidangField
Jenisradioisotop
Type of radioisotope
PenggunaanradioisotopUses of the radioisotope
PerubatanMedicineRadioisotopdigunakandalamdiagnosispenyakittertentu,untukmendapatkanmaklumatbagitentangorganyangkhususbagipesakitataumerawatpenyakit.Radioisotopes are used in the diagnosis of certain diseases, provides information on the specific organs of a patient or treat diseases.
Natrium-24Sodium-24
• Iamempunyaisetengahhayatselama 15jam dandigunakan
untukmengesankedudukan darahbeku (thrombosis)dalam
salurdarah .
It has a half-life of 15 hours and is used to detect the positions of blood clots (thrombosis) in veins .
• Natrium-24disuntikkedalamsalurandarahdansinar gama dansinarbetayangdipancardikesanolehkamerasinardariluarbadan.
Sodium-24 is injected into the blood stream and gamma rays and beta rays emitted are detected by a ray camera outside the body.
Teknetium-99Technetium-99
• Iamempunyaisetengahhayatselama 6jam dandigunakan
untukmengkaji darahdalamjantung .
It has a half-life of 6 hours and is used to study the blood in the heart .
• Iahanyamemancarkansinaran gama dantidakmenghasilkanzarahalfaatauzarahbetayangberbahayadidalambadan.
It emits only gamma rays and produces no harmful alphas or betas inside the body.
Xenon-133Xenon-133
• Iamempunyaisetengahhayatselama 5hari dandigunakan
untukmengkajifungsi paru-paru .
It has a half-life of 5 days and is used in studying lung functions.
• Pesakitdimintauntukbernafasmenggunakanudarayangmengandungigasxenon-133.A patient is asked to breathe air containing the gas xenon-133.
• Sinaran gama yangdipancarkandikajimenggunakankameragamayangmenghasilkangambarparu-parupesakitdarisinarangamayangditerima.
The gamma rays emitted are studied using a gamma camera which produces a picture of patient’s lungs from the gamma radiation each one receives.
• Pesakitkemudiannyaakanmenghembuskeluarsemuaxenondanhanyamenerimasinarandaridosyangkecil.The patient soon breathes out all the xenon and receives only a tiny dose of radiation.
Iodin-131Iodine-131
• Iamempunyaisetengahhayatselama 8hari .Iamemancarkansinargamadandigunakanuntukmengesan
perubahandalamkelenjartiroid .
It has a half-life of 8 days . It emits gamma rays and is used for
detecting changes in the thyroid glands .
Iodin-123Iodine-123
• Iamempunyaisetengahhayatselama 13jam .Iadigunakan
untukmengesan buahpinggangyangtersumbatdalampesakit .
It has a half-life of 13 hours . It is used to detect blockage in the
kidneys of patients.
05-Physic F5 2015 (FSY5p).indd 200 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.201
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
Iodine-125Iodine-125
• Iamempunyaisetengahhayatselama 60hari .Iadigunakan
untuk menganggarkanjumlahdarah denganmenyuntikserumalbumin(HSA)yangtelahditentukanisipadunya.
It has a half-life of 60 days . It is used to estimate the volume of blood by injecting a measured volume of human serum albumin (HSA).
Kobalt-60Cobalt-60
• Iamempunyaisetengahhayatselama 5tahun .Iadigunakansecarameluasuntukmengubatipenyakitdenganmemberikandossinar
gama yangbanyakuntuk mengubatikanserdalaman .
It has a half-life of 5 years . It is widely used to give patients a large dose
of gamma radiation for the treatment of internal cancers . • Alursinargamadipancarkantepatkepadakanserdaripadasumberkobaltdiluar.A restricted beam of gamma radiation is carefully directed at the cancer site from an external cobalt source.
PerindustrianIndustry
Strontium-90Strontium-90
• Iamempunyaisetengahhayatselama 29tahun .Iadigunakan
untukmengukur ketebalankertas dalamperindustriankertas.
It has a half-life of 29 years . It is used to measure the thickness
of paper in paper industry.
• Iamemancarkanzarah beta .
It emits beta radiation.
Natrium-24Sodium-24
• Iamempunyaisetengahhayatselama 15jam yangdigunakan
untukmenguji kebocoranpaipdibawahtanah .Natrium-24ditambahkandalamairdalamtangkipenyimpanan.
It has a half-life of 15 hours and is used to test for leakage of
underground pipes . Sodium-24 is added into the water in storage tank. • TiubG-Mdigerakkandiataspaipbawahtanah,kebocorandapatdikesan.A G-M tube is moved above the underground pipe, a leakage can be detected.
Polonium-210Polonium-210
• Iamempunyaisetengahhayatselama 140hari .Iamemancarkan
zarahalfa.Iadigunakanuntuk meneutralkancasstatikplatfotografi ataucaspadapakaian.
It has a half-life of 140 days . It emits alpha radiation. It is used to
neutralise static charges in photographic plates or charges on clothes.
• Zarahalfa mengionkanzarah-zarahudarakepadaionpositifdanionnegatifyangmanaiameneutralkanplatfotografiataupakaian.
The alpha particles ionise the air particles into positive and negative ions which neutralise the photographic plates or the clothes.
Kobalt-60Cobalt-60
• Iamempunyaisetengahhayatselama 5tahun .Iadigunakan
untukmengesankimpalandalam strukturkeluli dansaluranpaip.
It has a half-life of 5 years . It is used to check welds in steel structures and pipelines.
• Sinaran gama darisumberkobalt-60yangbesardiletakkandisisistrukturkeluliyangterdedahdanplatfotografidiletakkandisisiyangbertentangan.
Gamma radiation from a large cobalt-60 source placed on one side of a steel structure exposes a photographic plate at the other side.
05-Physic F5 2015 (FSY5p).indd 201 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 202
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
Americium-241Americium-241
• Iamempunyaisetengahhayat 430tahun .Iadigunakandalam
pengesanasap .
It has a half-life of 430 years . It is used in a smoke alarm
.
• Americium-241memancarkanzarah beta yangmengionkanudara.
Americium-241 emits beta particles which ionise air. • Udarayangtelahdiionkankemudiannyaakanmengkonduksikanelektrikyangmembenarkanarusyangkecilmengalirmelaluinya.The air ions will then conduct electricity allowing a small current to flow through.
• Apabilaasapmemasukipenggera,zarahasapmasukmelaluizarah
beta, mengurangkan pengionandan arus melaluipenggera.When smoke enters the alarm, the smoke particles get in the way of the beta
radiation, thus reducing the ionisation and the current across the alarm.
PertanianAgriculture
Fosforus-32Phosphorus-32
• Iamempunyaisetengahhayatselama 14hari .Fosforus-32
digunakansebagaipenyurihuntukmengkaji keberkesananbaja .
It has a half-life of 14 days . Phosphorus-32 is used as a tracer in the
study of the effectiveness of fertilizers . • Tumbuh-tumbuhandisiramdengancecairyangmengandungifosforus-32.The plants are watered with a solution containing phosphorus-32.
Kobalt-60Cobalt-60
• Iamempunyaisetengahhayatselama 5tahun .Sinar
gama memancarkankobalt-60yangbolehdigunakandalam
pengawetanmakanan .
It has a half-life 5 years . The gamma radiation emits from
cobalt-60 can be used for food preservation .
• Sesetengahtempatsimpananmakanansepertibijirindankacangkering,selalunyadiserangolehseranggasemasadisimpan.Some foodstuffs, like grain and dried beans, are often attacked by pests while in storage.
• Rawatanpemancaranmembunuhseranggaperosakinidanmengurangkankerugian.Radiation treatment kill these pests and reduces the losses.
• Sinar gama jugadigunakanuntuk mengawalserangga
perosakyangmemusnahkantanaman .
The gamma radiation is also used to control insect pests
which damage crops .
ArkeologiArchaeology
Karbon-14Carbon-14
• Iamempunyaisetengahhayat 5700tahun .Iadigunakanuntuk
mengukurusiaspesimenarkeologi denganmenggunakankaedahpentarikhankarbon.
It has a half-life of 5 700 years . It is used to measure the age of archaeological specimens by carbon-dating method.
Uranium-238Uranium-238
• Iamempunyaisetengahhayatselama 5000jutatahun .
Iadigunakanuntukmengukur masageologi .
It has a half-life of 5 000 million years . It is used to measure the
geological time .
05-Physic F5 2015 (FSY5p).indd 202 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.203
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
Unitjisimatom(u.j.a.)Atomic mass unit (a.m.u.)
• Satu unitjisimatom (u.j.a.)ialahjisimbagisatuperduabelas
daripadajisimsatuatomkarbon-12,12
6C.
One atomic mass unit (a.m.u.) is 112
of the mass of the carbon-12 atom, 12
6C.
PembelahannukleusNuclear Fission
92143
• Pembelahannukleusadalah pemecahan satu nukleusyang
berat kepada duanukleusyanglebihringan ,sertamenghasilkanduaatautiganeutronbebasdanmembebaskan
tenaga yangsangatbesar.
Nuclear fission is the splitting of a heavy nucleus into two lighter nuclei , which emits either two or three neutrons and releases large
amounts of energy .
• Pembelahanberlakuapabilasatunukleus dihentam olehsatu
neutron .
Fission occurs when the nucleus of an atom is bombarded with a neutron .
TindakbalasberantaiChain reactions
NeutronNeutrons
U-235nukleusnucleus U-235
PembelahanspontanSpontaneous fission Lebihbanyak
pembelahanterhasildaripadahentamanbeberapaneutronMore fission triggered by neutrons
• Tindakbalasberantaiialah prosestindakbalaspengekalan yangmana
hasiltindakbalasinibolehmemulakantindakbalasseterusnya
yangserupa . (prosespembelahannukleusyangberterusan)
A chain reaction is a self-sustaining reaction in which the
products of a reaction can initiate another similar reaction .• Dalamtindakbalasberantai,pembelahanyangseterusnyabergantung
kepadapenghasilan nukleusbaru dan hentamanneutron .
In nuclear chain reactions the succession depends on the production and capture of neutrons .
• Satu neutron menghentam nukleusuranium maka2atau
3neutrondihasilkan.
A neutron bombards a uranium nucleus and 2 or 3 neutrons are produced.
• Neutronyangdihasilkaniniakanberlanggardengan nukleusuranium yanglain.
These neutrons produced will bombard another uranium nucleus .• Untuksetiaptindakbalas,lebihbanyakneutronterhasildan
menyebabkanberlakunya tindakbalasberantai ,sehinggajisim
nukleusuraniummencapai jisimgenting .
For each reaction, more neutrons are produced causing a chain reaction
until the mass of the uranium nucleus reaches a critical mass .
• Apabilaatomuraniummembelahsecaraberterusan,jumlahtenaga yangbesardibebaskanuntuksetiaptindakbalas.
As uranium atoms continue to split, a significant amount of energy is released during each reaction.
• Haba yangdibebaskanbolehdimanfaatkandandigunakan
untukmenjana tenagaelektrik .
The heat released is used to generate electrical energy .
Memahami Tenaga Nuklear Understanding Nuclear Energy
5.4
05-Physic F5 2015 (FSY5p).indd 203 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 204
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
• Tindakbalasberantaiyangterkawaldigunakandalamstesenkuasanuklear.A controlled chain reaction is used in nuclear power stations.
• Tindakbalasberantaiyangtidakterkawaldigunakandalam
bomnuklear .
An uncontrolled chain reaction is used in nuclear bombs .
JisimgentingCritical mass
• Jisimminimum bagi pembelahan nukleusyangakanmengekalkantindakbalasberantai.
The minimum mass of nuclear fission that will sustain a nuclear chain reaction.
PelakurannukleusNuclear fusion
NukleusDeuteriumDeuterium nucleus
DeuteriumDeuterium
NukleusHeliumHelium nucleus
2
1H+
2
1H
3
2H+
1
0n+Tenaga
Energy
+Tenaga Energy
• Pelakurannukleusadalah percantumanduanukleusyangringan
menjadinukleusyang lebihberat denganmembebaskan
tenaga yangsangatbesar.
Nuclear fusion is the combining of two lighter nuclei to form a heavier
nucleus with the release of large amount of energy .• Mataharimendapattenaganyadaripelakurannukleushidrogen.
The Sun get its energy from the fusion of hydrogen nuclei.
• Apabiladuaisotophidrogen-2nukleus berlanggardenganhalaju
yangtinggi ,iabolehbercantumdanmenghasilkannukleusyanglebihberat.Tenagayangbesardibebaskan.
When two hydrogen-2 nuclei moving at high speed collide , they combine together to produce a heavier nucleus. A large amount of energy is released.
• Suhu gasmesti tinggi supayanukleus-nukleus
yangringanmempunyai tenagakinetikpurata yangtinggi.
Disebabkankeperluansuhuyangtinggi,pelakurannukleusjugadikenali
sebagai tindakbalastermonuklear .
The temperature of a gas must be high , giving a high average kinetic energy . Due to the requirement of high temperature, nuclear
fusion is also known as a thermonuclear reaction .
TenaganuklearNuclear Energy
1 Kedua-duapembelahannukleusdanpelakurannukleusmembebaskan tenaga yangsangatbesar.
Both nuclear fission and nuclear fusion release a large amount of energy .
2 Sumbertenagainiadalahdaripada jisimyanghilang dalamtindakbalasnuklear.
The source of this energy is from the loss of mass in nuclear reactions.
3 Jumlah jisim zarahsebelumtindakbalasadalah lebihdaripada jumlahjisimzarahselepastindakbalas.
Cacatjisim(jisimyanghilang)=jumlahjisimsebelumtindakbalas–jumlahjisimselepastindakbalas
The sum of the masses of the particles before the reaction is more than the sum of the masses of the particles after the reaction.
Mass defect = sum of the masses before the reaction – sum of the masses after the reaction
4 Jisimyanghilang(cacatjisim)dalamtindakbalasberantaibermaksudbahawajisimtersebuttelahberubah
menjadi tenaga .
A loss of mass (or mass defect) in a nuclear reaction means that the mass has been changed to energy .
05-Physic F5 2015 (FSY5p).indd 204 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.205
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
5 MenurutAlbertEinstein,hubunganantarajisimdantenagadiberikanolehpersamaan:According to Albert Einstein, the relationship between the mass and the energy is given by the equation:
E = mc2
DimanaE=tenagadibebaskan/Where E = energy released m=jisimyanghilangataucacatjisim/m = loss of mass or mass defect c=halajucahaya=3×108ms–1/c = speed of light = 3 × 108 m s–1
Latihan / Exercise
1 Polonium-210mengalamireputanalfauntukmenjadiplumbum-206.PersamaanreputanialahPolonium-210 undergoes alpha decay to become plumbum-206. The equation for the decay is:
210
82Po
206
84Pb
4
2He Energy+ +
Maklumattambahan:/Additional information:
JisimPo/Mass Po =209.982a.m.u.
JisimPb/Mass Pb =205.969a.m.u.
JisimHe/Mass He =4.004a.m.u. 1a.m.u.=1.66×10–27kg c=3×108ms–1
210
82
206
84
4
2
210
82
206
84
4
2
Menggunakanpersamaandanmaklumatdiatas,kirakanUsing the equation and the information above, calculate (a) cacatjisim/the mass defect(b) tenagadibebaskan/the energy released
Penyelesaian/ Solution
(a) Cacatjisim/Mass defect=Jisim/MassPo–(Jisim/MassPb+Jisim/MassHe) =209.982a.m.u.–(205.969a.m.u.+4.004a.m.u.) =0.009a.m.u. (b) E=mc2
=(0.009×1.66×10–27)kg×(3×108ms-1)2
=0.1345×10–11J =1.345×10–12J
2 Dalamujian letupannuklear,0.5guraniumtelahditukarkepada tenagadalammasa0.05µs.Berapakahkuasadalamletupannuklear?
[Halajucahaya=3.0×108ms–1]In a test of nuclear explosion, 0.5 g of uranium has been converted to energy in 0.05 µs. What is the power of the nuclear explosion?[Velocity of light = 3.0 × 108 m s–1]
Penyelesaian/ Solution
Kuasa/Power,P= Et
= mc2
t
=(0.5×10–3)kg× (3.0×108ms-1)2
(0.05×10–6)s =9×1020W
210
82
206
84
4
2
05-Physic F5 2015 (FSY5p).indd 205 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 206
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
KelebihandankekuranganpenggunaanpembelahannuklearAdvantages and disadvantages of using nuclear fission
KelebihanAdvantages
KekuranganDisadvantages
• Kosmenggunakankuasanuklearsamasepertiarang,
jadiianya tidakmahal .
Nuclear power costs about the same as coal, so it isnot expensive .
• Iamenghasilkan tenaga yangsangat
besar denganhanyamenggunakanbahanapiyangsedikit.
It produces huge amounts of energy from small amounts of fuel.
• Terdapatbanyaksimpananbahanapinukleardidunia.Vast reserves of nuclear fuel in the world.
• Iatidakmenghasilkan asap atau
karbondioksida .
It does not produce smoke or carbon dioxide .
• Iatidakmenyumbangkepada kesanrumahhijau .
Iamenyebabkanpembaziranyang kurang berbandingdenganpembakaranbahanapi.
It does not contribute to the greenhouse effect . It
produces less waste than fossil fuels.
• Pusatkuasanuklear memerlukanbahanapiyangkurangberbandingdenganstesenyangmenggunakanbahanapifosil.
Nuclear power stations need less fuel than stations which use fossil fuels.
• Menghasilkan radioisotopyangberguna yangbolehdigunakandalamperindustrian,perubatan,pertaniandankajian.
Produces useful radioisotopes as by products that can be used in industry, medicine, agriculture and research.
• Langkah-langkahkeselamatandalampengurusanreaktornuklearadalahmajudanselamat.Safety procedures in the administration of nuclear reactors are very advanced and safe.
• Kospermulaanuntukmembentukdanmembinastesen
kuasanuklearadalah sangattinggi .
The initial cost to design and build a nuclear power station is very high .
• Berisikotinggiuntukberlakukemalanganjika
tindakbalasberantai hilangkawalan,meletupataukebocoranbahanradioaktifyangbesarbolehberlaku.Always a risk for accidents to occur if a
chain reaction goes out of control. Explosion or leakage of large amounts of radioactive substance may happen.
• Rodbahanapi yangdigunakansangatpanasdanmempunyaisetengahhayatyanglama.
Fuel rods used are very hot and highly radioactive with very long half-lives.
• Proseduryangmahaldiperlukanuntukmenyejukkanroddanmenyimpannya.
Expensive procedures are required to cool down the rods and store them.
• Airpanasyangdilepaskandaristesenkuasanuklear
bolehmenyebabkan pencemaranterma .
The hot water discharged from the nuclear power stations can
cause thermal pollution .
• Pekerjayangbekerjadipusatkuasanukleardanyang
tinggalberdekatanboleh terdedahkepada
pemancaranyangberlebihan .
People who work in the nuclear power station and those living
nearby may be exposed to excessive radiation
.
Kesedaran kepentingan pengurusan baik terhadap bahan radioaktifRealising the importance of proper management of radioactive substances
5.5
05-Physic F5 2015 (FSY5p).indd 206 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.207
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
CadangandanpeneranganSuggestions and explanation
CadanganSuggestions
PeneranganExplanation
Peralatanyangdigunakandalammenguruskansumberradioaktif.The equipment to be used in handling a radioactive source.
• Gunakanforsepataurobotkawalanjauh.Jarakantarasumberdanbadanmestilahjauh.Use forceps or remote control robot. Maintain a safe distance from the source.
• Pakaipenutupmukauntukmelindungimatadaripadaterdedahkepadapemancaran.Wear a mask to protect the eyes from radiation exposure.
• Pakaikotyangkalispemancaransupayapemancarantidakakanmenembusibadan.Wear a radiation-proof coat so that the radiation cannot penetrate the body.
• Pakailencanafilemuntukmengesankadarradiasiyangterdedah.Wear a film badge to detect amount of radiation exposed.
Pengubahsuaiandariaspekkaedahpenyimpananuntukmemastikanpenyimpanansumberradioaktifyangselamat.Modifications for storage method to ensure safe keeping of the radioactive source.
• Gunakankotakplumbumataukonkrityangtebal.Inibolehmenghalangradiasidaripadakebocorankekeadaansekeliling.Use a lead box or thick concrete. This can prevent radiation from leaking to the surrounding.
• Letakkansimbolpemancaranpadakotaksimpan.Iabolehmemberiamarankepadapenggunalainterhadapbahayadaripadasumberpemancaran.Put a radiation symbol on the storage box. It can warn other users about the danger of the radiation source.
Langkahberjaga-jagayangdiperlukanapabilamengendalikansumberradioaktif.Other precautions that need to be taken when handling a radioactive source.
• Pastikanmasapendedahanadalahdalamjangkamasayangsingkat.Keep exposure time as short as possible.
1 Rajah1menunjukkansinaran-sinaranradioaktifdidalammedanelektrik.Diagram 1 shows radioactive rays in electric field.
Sumberradioaktif
Radioactive source T
S
R
Rajah1/Diagram 1
Sinaryangmanakahmewakilizarahalfa?Which of the radioactive ray is alpha particles?
A RB SC T
atihan Pengukuhan / Enrichment ExerciseL2 Satu tengkorak manusia yang dijumpai
menunjukkankeradioaktifan30bilanganpersaat.Tengkorakbarumenunjukkankeradioaktifan120bilanganpersaat.Jikaseparuhhayatkarbon-14adalah5600tahun,berapausiatengkorakitu?An old human skull that has been found, produces radioactive rays with radioactivity of 30 counts per second. A new skull produces radioactivity of 120 counts per second. If the half life of Carbon-14 is 5 600 years, how old is the skull?
A 11200tahun/yearsB 22400tahun/yearsC 168000tahun/yearsD 672000tahun/years
05-Physic F5 2015 (FSY5p).indd 207 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 208
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
Jadual4menunjukkankeputusanpenyiasatan.Table 4 shows her results.
SinarlatarbelakangBackground count
25bilanganperminit25 counts per minute
BilangandengansumbersahajaCount with source only
630bilanganperminit630 counts per minute
BilangandengansumberdankertaspenghadangCount with source and paper absorber
630bilanganperminit630 counts per minute
Bilangandengansumberdanpenghadangaluminiumketebalan3mmCount with source and aluminium absorber 3 mm thick
180bilanganperminit180 counts per minute
Jadual4/Table 4
Sumberitumemancarkan/The source emitsA zarah-zarahalfadanbeta. alpha and beta particles.B zarahbetadansinargama. beta particles and gamma rays.C zarahbetasahaja beta particles only.D sinargamasahaja. gamma rays only.
5 Persamaan menunjukkan penyusutan jisimnukleusX.The equation shows the decay of the nuclide X.
226
88X P
QY+4
2He ApakahnilaiPdanQ?
What are the values of P and Q?
P Q
A 230 90
B 230 86
C 222 90
D 222 86
6 Tindakbalasnuklearbagisatunukleusradium-226mengalamicacatjisimsebanyak4.3409g.Hitungtenaga yang dibebaskan dalam tindak balasnuklearini.The nuclear reaction of one nucleus of radium-226 experiences a mass defect of 4.3409 g. Calculate the energy released in this nuclear reaction.
[c=3.0×108ms–1]A 1.954×10–13JB 3.907×10–13JC 7.814×10–13JD 1.293×10–14J
3 Seorangpelajaringinmengkajijenissinarradioaktifyangdipancarkanolehsumberradioaktif.Rajah3menunjukkansusunanradasyangdigunakan.A student wishes to study the type of radioactive radiation emitted by a radioactive source. The arrangement of the apparatus used is as shown in Diagram 3.
SumberradioaktifRadioactive source
TiubGeigerMuller
Geiger Muller Tube
PenyerapAbsorber Meterkadar
Rate meter
Rajah3/Diagram 3
Jadual 3 menunjukkan keputusan kajian yangdilakukan.Table 3 shows the result of the study.
PenyerapAbsorber
BacaanmeterkadarRate meter reading
Udara/Air 120
Kertas/Paper 119
Aluminium3mmAluminium 3 mm
50
Plumbum10cmLead 10 cm
50
Jadual3/Table 3
Apakahjenissinaryangdipancarkanolehsumberradioaktifitu?/What type of radiation is emitted by the radioactive source?A Zarahalfa/Alpha particleB Zarahbeta/Beta particleC Sinargama/Gamma rayD Zarahalfadanbeta/Alpha and beta particles
4 Seorang pelajar menyiasat tentang kuasapenembusansesuaturadiasidaripadasumbernyasepertiRajah4.A pupil investigates the penetrating power of radiation from a radioactive source as in Diagram 4.
1cm
TiubGeigerMullerGeiger Muller tube
PenyerapAbsorber
KepembilangTo counter
RadioaktifRadioactive
Rajah4/Diagram 4
05-Physic F5 2015 (FSY5p).indd 208 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.209
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
7 Persamaanberikutmewakilipelakurannukleus.The following equation represents a nuclear fusion.
2
1H+3
1H 4
2He+1
0n+TenagaEnergy Jikatenagayangdibebaskansemasatindakbalas
tersebutituialah5.64x10–12J,hitungcacatjisimdaripadatindakbalasitu.If the energy released in the above reaction is 5.64 × 10–12 J, calculate the mass defect from the reaction.
[1u=1.66×10–27kg;c=3.0×108ms–1]
A 0.009432uB 0.018863uC 0.037726uD 0.075452u
8 Jadual 8 menunjukkan maklumat bagi empatsampelradioaktif.
Table 8 shows the information of four different radioactive samples.
Sampelradioaktif
Radioactive sample
Setengahhayat
Half-life
Sinaranradioaktif
Radioactive emission
Kobalt-60Cobalt-60
5tahun5 years
GamaGamma
Strontium-90Strontium-90
28tahun28 years
BetaBeta
Iodin-131Iodine-131
8hari8 days
GamaGamma
Polonium-210Polonium-210
140hari140 days
AlfaAlpha
Jadual8 Table 8
Sampel manakah yang paling sesuai untukpemeriksaanginjal?
Which sample is most suitable to be used for examining the kidney?A Kobalt-60 Cobalt-60B Strontium-90 Strontium-90C Iodin-131 Iodine-131D Polonium-210 Polonium-210
9 Jadual9menunjukkanempatnuklidradioaktif. Table 9 shows the half-life of four radioactive nuclides.
NuklidradioaktifRadioactive nuclides
SetengahhayatHalf-life
Ga 4063s
Rn 50s
Bi 128s
Pb 1600s
Jadual9/Table 9
Reputan radioaktif salah satu daripada nuklidraddioaktif tersebut adalah ditunjukkan padaRajah9.
The radioactive decay for one of these radioactive nuclides is shown in Diagram 9.
10
20
30
40
50
60
200
Kadarbilang/bilangsesaatCount rate / counts per second
60 8040 100 120Masa/saatTime/seconds
Rajah9 Diagram 9
Yangmanakahmerupakannuklidradioaktifdalamgrafitu?Which is the decaying radioactive nuclide in the graph?
A GaB RnC BiD Pb
10 Pernyataan yang manakah benar tentangkegunaanbahanradioaktif?Which statement is true about the use of radioactive substance?
A Mengenalpastiwangkertaspalsu. To identify counterfeit bank notes.B Menentukan kandungan bagasi penumpang
kapalterbang. To determine the contents in the baggage of airplane
passengers.C Menentukanjantinajanindalamrahim. To determine the sex of a foetus.D Sebagaikawalanperosakdalampertanian. As pest control in agriculture.
05-Physic F5 2015 (FSY5p).indd 209 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 210
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
1 Rajah1.1adalahsebahagianlengkungpereputansatusampelisotopradioaktifyangmemancarkansinaralfa(α).Diagram 1.1 is part of the decay curve for a sample of an α-emitting radioactive isotope.
25
50
75
100
50
%aktiviti% activity
15 2010
Masa/hariTime/days
Rajah1.1 Diagram 1.1
(a) Apakahmaksudisotop? What is meant by isotope?
Atomunsuryangmempunyainomborprotonyangsamatetapinombornukleonyangberbeza.
Atoms of elements which have same proton number, but different nucleon number.
(b) BerdasarkanRajah1.1, Based on Diagram 1.1,
(i) tentukanseparuhhayatisotop. determine the half-life of the isotope.
Daripadagraf,separuhhayatisotop=3.5hari.
From the graph, the half-life of the isotope = 3.5 days.
(ii) LengkapkanlengkungandalamRajah1.1sehinggamasa=20hari.Plotsecaratepathubungannilaiperatusaktivitidenganmasa.
Complete the curve in Diagram 1.1 as far as time = 20 days. Plot the exact corresponding values of the percentage activity and time.
(c) RadasditunjukkandalamRajah1.2bagieksperimenuntukmencarijulatzarahαdidalamudara. In an experiment to find the range of α-particles in air, the apparatus in Diagram 1.2 is set-up.
Sumberzarahαα-particle source
PengesanDetector
PembarisRuler
Rajah1.2 Diagram 1.2
oalan Struktur / Structure QuestionsS
05-Physic F5 2015 (FSY5p).indd 210 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd.211
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
KeputusaneksperimenditunjukkandalamJadual1. The results of this experiment are shown in Table 1.
Jarakantarasumberdanpengesan/cmDistance from source to detector / cm 1 2 3 4 5 6 7 8 9
Kadarpembilang(bilang/minit)Count rate (counts / minute) 681 562 441 382 317 20 19 21 19
Jadual1 Table 1
(i) Namakansatupengesanyangsesuaiuntukmengesanzarahαdalamudara. Name one suitable detector to detect α-particles in air.
TiubG-M
Geiger Muller tube
(ii) Nyatakansebabmengapaterdapatkadarbilanganpadajarak9cmdaripadasumber. State the cause of the count rate at a distance of 9 cm from the source.
BacaanLatarBelakang.
Background reading.
(iii) Anggarkankadarbilanganyanghanyadipengaruhiolehjarak2cmdaripadasumber. Estimate the count rate that is only due to the source at a distance of 2 cm.
562–20//19//21=542//543//541bilang/minit.
562 – 20//19//21 = 542// 543// 541 counts/min.
(iv) BerdasarkanJadual1,apakahjarakmaksimumzarahαbolehbergerakdalamudara. Using Table 1, what is the maximum distance α-particles can travel in air?
5cm
(v) Jastifikasijawapanandabagi(c)(iv). Justify your answer to (c)(iv).
1 Pada5cm,bacaandaripadapengesanmeningkatdengancepat.
At 5 cm, the reading form detector increase rapidly.
2 Dalamskala/bilanganyangbesar,menunjukkankewujudanzarahα.
In large scale/ number, shows the existing of α-particles.
2 Polonium-210adalahsatu radioisotopbagipolonium.Suatusampel radioisotopyangmengandungi400gPolonium-210mengalamiprosesreputan.Setengah-hayatPolonium-210adalah140hari.Polonium-210 is a radioisotope of polonium. A radioisotope sample that contains 400 g of Polonium-210 undergoes a decay process. The half-life of Polonium-210 is 140 days.(a) Apakahmaksudsetengah-hayat? What is the meaning of half-life?
Setengahhayatialahmasayangdiambiluntukjisim/aktivitiradioisotopmenjadiseparuhdaripadanilai
jisim/aktivitiasalnya.
Half-life is the time taken for the mass/activity of radioisotope to become half of its mass/activity.
(b) BerisatusebabmengapaPolonium-210mengalamiprosesreputan. State one reason why Polonium-210 undergoes a decay process.
Untukmenjadilebihstabil.
To become more stable.
05-Physic F5 2015 (FSY5p).indd 211 10/15/15 3:15 PM
© Nilam Publication Sdn. Bhd. 212
MODUL • Fizik TINGKATAN 5
UN
IT 5
UN
IT 5
(c) (i) HitungjisimPolonium-210selepas420hari. Calculate the mass of Polonium-210 after 420 days.
(ii) PadaRajah2,lakargrafuntukmenunjukkanprosesreputanPolonium-210. On Diagram 2, sketch a graph to show the decay process of Polonium-210.
400
200
300
100 300200 400
100
0
Jisim(g)Mass (g)
Masa/hariTime/days
Rajah2/Diagram 2
400g 100g140
200g140140
T1—2
T1—2
T1—2
50g
Selepas420hari,jisimPolonium-210yangmasihaktif=50g.After 420 days, the mass of Polonium-210 that is still active = 50 g.
05-Physic F5 2015 (FSY5p).indd 212 10/15/15 3:15 PM