Lipotso tsa Mehlala mabapi le Puisano ea Fisiks ea Nyutlelie le Radioactivity
Fisiks ea nyutlelie le radioactivity ke makala a fisiks a sebetsanang le thuto ea li-nuclei tsa athomo le liketsahalo tsa ho bola ha mahlaseli a kotsi tse etsahalang li-nuclei tsena. Ho tseba likhopolo tsena tsa motheo ho bohlokoa mafapheng a fapaneng, ho kenyeletsoa bongaka, matla a nyutlelie le saense ea thepa. Sehloohong sena, re tla buisana ka mathata a 'maloa a mehlala a amanang le fisiks ea nyutlelie le radioactivity, hammoho le litlhaloso tsa ona, ho thusa kutloisiso ea hau.
Selelekela sa Motheo ho Fisiks ea Nyutlelie le Radioactivity
Pele re kena lipotsong tsa mohlala, ke mohopolo o motle ho hlahloba likhopolo tse ling tsa motheo:
– Atomic nucleus: E entsoe ka liprothone le li-neutron. Liprothone li na le charge e ntle, ha li-neutron li sa tjhaje.
– Radioactivity: Ts'ebetso ea ho bola ha li-nuclei tse sa tsitsang ho ba li-nuclei tse tsitsitseng haholoanyane ka ho ntšoa ha likaroloana kapa mahlaseli.
– Mefuta ea ho bola ha mahlaseli a kotsi: ho bola ha Alpha (\(\alpha\)), beta (\(\beta\)), le gamma (\(\gamma\)).
– Molao oa ho Bola ha Mahlaseli a Leseli: O hlalosa kamoo palo ea li-nuclei tsa mahlaseli a leseli e fokotsehang kateng ha nako e ntse e ea.
Mohlala oa Potso ea 1: Matla a Boima le ho Bola
Potso:
Ntlheng ea uranium-238 e bola ho ba thorium-234 ka ho ntšoa ha karoloana ea alpha. Haeba boima ba uranium-238 e le 238.0508 u, boima ba thorium-234 ke 234.0436 u, 'me boima ba karoloana ea alpha e le 4.0026 u, bala matla a lokolloang ho bola hona.
Puisano:
Matla a lokollotsoeng ts'ebetsong ea ho bola a ka baloa ho sebelisoa kamano pakeng tsa boima le matla a fanoeng ke equation ea Einstein \(E=mc^2\).
1. Bala boima bo sieo:
\( \Delta m = (boima_{U-238}) – (boima_{Th-234} + boima_{\alpha}) \)
\( = 238.0508 – (234.0436 + 4.0026) \)
\( = 238.0508 – 238.0462 \)
\( = 0.0046\, u \)
2. Fetolela boima bo lahlehileng ho ba matla u sebelisa \( c^2 \):
\( E = \Delta m \times 931.5\, MeV/u \)
\( = 0.0046 \makgetlo a 931.5 \)
\( \hoo e ka bang 4.29\, MeV \)
Kahoo, matla a ntshitsweng ho bola hona ke a ka bang 4.29 MeV.
Mohlala oa Potso ea 2: Halofo ea Bophelo le Mosebetsi
Potso:
Sampole ea mahlaseli a kotsi qalong e na le ts'ebetso ea 1000 Bq. Kamora lihora tse 10, ts'ebetso ea eona e fokotseha ho 125 Bq. Fumana halofo ea bophelo ba ntho e nang le mahlaseli a kotsi.
Puisano:
Mosebetsi (A) oa ntho e ntšang mahlaseli a kotsi o lekana ka ho toba le palo ea li-nuclei tsa mahlaseli a kotsi (N). Molao oa ho bola ha mahlaseli a kotsi o re:
\[ A(t) = A_0 e^{-\lambda t} \]
Moo \( \lambda \) e leng kamehla ya ho bola:
1. Bala kamehla ea ho bola (\( \lambda \)):
\[ \frac{A(t)}{A_0} = e^{-\lambda t} \]
\[ \frac{125}{1000} = e^{-\lambda \times 10} \]
\[ 0.125 = e^{-\lambda \times 10} \]
\[ \ln(0.125) = -\lambda \makgetlo a 10 \]
\[ \lambda = -\frac{\ln(0.125)}{10} \]
2. Fumana halofo ea bophelo (\( T_{1/2} \)):
\[ T_{1/2} = \frac{\ln(2)}{\lambda} \]
\[ \lambda = \frac{\ln(8)}{10} = \frac{2.079}{10} = 0.2079 \, h^{-1} \]
\[ T_{1/2} = \frac{\ln(2)}{0.2079} \hoo e ka bang 3.3 \, dihora \]
Bophelo ba halofo ea ntho e ntšang mahlaseli a kotsi ke lihora tse ka bang 3.3.
Mohlala oa 3: Beta Decay le Antineutrinos
Potso:
Sekotwana sa Cobalt-60 se bola ka ho bola ha beta-minus ho etsa sekotwana sa Nickel-60. Ngola karabelo ea nyutlelie bakeng sa ho bola hona 'me u khetholle likaroloana tse amehang.
Puisano:
Ho bola ha Beta-minus (\(\beta^-\)) ho etsahala ha neutron e ka har'a khubu ea athomo e fetoha proton, ha e ntse e ntša elektrone (\(\beta^-\)) le antineutrino (\(\bar{\nu}_e\)).
Karabelo ea nyutlelie bakeng sa ho bola hona ke:
\[ _{27}^{60}Co \rightarrow _{28}^{60}Ni^ + e^- + \bar{\nu}_e \]
Di mana:
– \( _{27}^{60}Co \) ke Cobalt-60.
– \( _{28}^{60}Ni^ \) ke Nickel-60 e le boemong ba thabo.
– \( e^- \) ke elektrone (karoloana ea beta-minus).
– \( \bar{\nu}_e \) ke antineutrino.
Nickel-60 e bopiloeng hangata e boemong ba thabo 'me hangata e tla lokolla matla a mang ka mokhoa oa mahlaseli a gamma (\(\gamma\)) ho fihla boemong ba fatše. Karabelo e felletseng e ka ngoloa tjena:
\[ _{27}^{60}Co \rightarrow _{28}^{60}Ni + e^- + \bar{\nu}_e + \gamma \]
Mohlala oa Potso ea 4: Tekanyo ea Mahlaseli
Potso:
Haeba mohlodi wa mahlaseli a gamma o nang le tshebetso ya di-Curies tse 2 o bewa bohole ba mithara e le 1 ho tloha nthong mme mahlaseli a monywa ke ntho eo metsotso e 5, bala tekanyo ya mahlaseli a amohetsweng ke ntho eo ka di-rems. Nka hore bongata ba mahlaseli a kwahetsweng ke 0.5 rad ka Curie ka motsotso mme ntlha ya boleng ba mahlaseli a gamma ke 1.
Puisano:
1. Bala tekanyo ka rad:
\[ \text{Tekanyo (rad)} = \text{Bongata ba mahlaseli} \times \text{Activity} \times \text{Nako (metsotso)} \]
\[ = 0.5 \, rad/(Ci \cdot min) \ linako 2 \, Ci \ linako 5 \, min \]
\[ = 5 \, rad \]
2. Bala tekanyo ka li-brake:
\[ \text{Tekanyo (rem)} = \text{Tekanyo (rad)} \times \text{Ntlha ea Boleng} \]
\[ = 5 \, rad \makgetlo a 1 \, (bakeng sa gamma) \]
\[ = 5 \, rem \]
Tekanyo ea mahlaseli e amoheloang ke ntho ke 5 rem.
Ho koala
Ka ho ithuta mehlala ea mathata a kaholimo, re tšepa ho tebisa kutloisiso ea hau ea likhopolo tsa fisiks ea nyutlelie le radioactivity. Ho bohlokoa ho itloaetsa mathata a tšoanang khafetsa hore u be le boiphihlelo bo eketsehileng ba ho utloisisa le ho sebelisa likhopolo tsena tsa fisiks ea nyutlelie. Thuto e monate!
