Umphumela we-Photoelectric, Umphumela we-Compton, kanye ne-X-Rays
I-Pendahuluan
Ekuqaleni kwekhulu lama-20, izivivinyo eziningana ezibalulekile zashintsha ukuqonda kwethu uhlobo lokukhanya nezinto. Izenzakalo ezintathu ezibalulekile—umphumela we-photoelectric, umphumela we-Compton, kanye ne-X-ray—zidlale indima ebalulekile ekuthuthukisweni kwe-physics yanamuhla. Lesi sihloko sizoxoxa ngesinye salezi zenzakalo, indlela ezitholakale ngayo, kanye nemiphumela yazo kanye nokusetshenziswa kwazo kwisayensi nobuchwepheshe.
Umphumela we-Photoelectric
Ukutholwa Nokuqonda
Umphumela we-photoelectric wabonwa okokuqala nguHeinrich Hertz ngo-1887 lapho ethola ukuthi ukukhanya kwe-ultraviolet kungabangela izinhlansi zikagesi kuma-electrode. Kodwa-ke, incazelo eyanele yenkolelo ayizange ifike kwaze kwaba ngu-Albert Einstein ngo-1905. U-Einstein waphakamisa ukuthi ukukhanya kuqukethe i-quanta yamandla ebizwa ngokuthi ama-photon, angakhipha ama-electron ezindaweni zensimbi lapho emuncwa.
Ngokusho kwenkolelo-mbono ka-Einstein, amandla e-photon \(E\) anikezwa yi-equation:
\[ E = h\nu \]
lapho \( h \) kungukungaguquguquki kukaPlanck kanye \( \nu \) kungukuphindaphinda kokukhanya. Uma ama-photon anamandla anele eshaya indawo yensimbi, angakhipha ama-electron uma amandla e-photon makhulu kunomsebenzi wokusebenza \( \phi \) wensimbi:
\[ h\nu = \phi + KE \]
lapho \( KE \) kungamandla e-kinetic e-electron ekhishwe.
Ukuhlolwa Nokuqinisekiswa
URobert Millikan wenza uchungechunge lwezivivinyo phakathi kuka-1914 no-1916 ukuze ahlole umbono ka-Einstein. Imiphumela yakhe yayisekela ngokuphelele umbono ka-Einstein, okubonisa ukuthi amandla e-photon ahlobene ngqo nemvamisa yokukhanya futhi azimele ekuqineni kokukhanya.
Imiphumela kanye nezicelo
Umphumela we-photoelectric unikeza ubufakazi obuqondile bemvelo ye-quantum yokukhanya kanye nokuhlangana kwayo kwamagagasi nezinhlayiya. Lesi simo siyisisekelo ekuthuthukisweni kobuchwepheshe obufana namakhamera e-photovoltaic nama-CCD. Kubuchwepheshe be-photovoltaic, ama-photon avela elangeni asetshenziselwa ukukhipha ama-electron ngaphakathi kwento ye-semiconductor, okukhiqiza ugesi ongasetshenziswa njengomthombo wamandla.
Umphumela we-Compton
Ukutholwa Nokuqonda
Umphumela weCompton watholakala ngu-Arthur H. Compton ngo-1923. UCompton waphawula ukuthi lapho ama-X-ray eshayisana nama-electron akhululekile, ubude be-wavelength yama-X-ray ahlakazekile buba bude kunobude be-wavelength yokuqala. Lolu shintsho luncike ekhoneni lokusabalala futhi alunakuchazwa yi-classical wave theory yokukhanya.
UCompton uphakamise ukuthi ukungqubuzana phakathi kwe-photon ye-X-ray ne-electron kufanele kuphathwe njengokungqubuzana okunwebekayo phakathi kwezinhlayiya ezimbili. Amandla kanye nomfutho kuyalondolozwa kule nqubo. Isibalo sokushintsha kobude be-wavelength (esaziwa ngokuthi i-Compton shift) sinikezwa ngu:
\[ \Delta \lambda = \lambda' – \lambda = \frac{h}{m_ec} (1 – \cos \theta) \]
Kuphi:
– \( \lambda \) ubude besikhathi bokuqala be-X-ray.
– \( \lambda' \) ubude besikhathi be-X-rays ehlakazekile.
– \( h \) kuyinto engaguquki kaPlanck.
– \( m_e \) isisindo se-electron.
– \( c \) ijubane lokukhanya.
– \( \theta \) yi-engeli yokusabalalisa.
Ukuhlolwa Nokuqinisekiswa
UCompton wenza izivivinyo ngokukhanyisa ithagethi ye-graphite nge-X-rays nokulinganisa ubude bamaza e-X-rays ahlakazekile. Imiphumela yavumelana nezibikezelo zakhe zemfundiso, inikeza ubufakazi obuqinile bemodeli yama-photon njengezinhlayiya ezinamandla kanye nomfutho.
Imiphumela kanye nezicelo
Umphumela we-Compton uqinisekisa ubunjalo bezinhlayiya zama-photon futhi uqinisa inkolelo-mbono ye-quantum yemisebe ye-electromagnetic. Lesi simo sinezisetshenziswa ezibalulekile kwezokwelapha kanye nezinkanyezi. Ekuthathweni kwezithombe zezokwelapha, umphumela we-Compton usetshenziswa ku-computed tomography (CT) ukukhiqiza izithombe ezinesinqumo esiphezulu zomzimba wangaphakathi. Ku-astronomy, umphumela we-Compton usiza ukuqonda imisebe ye-cosmic kanye nesakhiwo sezinkanyezi.
I-X-ray
Ukutholwa Nokuqonda
Ama-X-ray atholwe nguWilhelm Conrad Röntgen ngo-1895. URöntgen wathola ukuthi imisebe engabonakali ingangena ezintweni eziqinile futhi ikhiqize izithunzi emapuletini ezithombe. Wabiza le misebe ngokuthi “ama-X-ray” ngenxa yemvelo yayo engaziwa.
Imisebe ye-X iwuhlobo lwemisebe kagesi enama-wavelength amafushane kakhulu (ama-nanometer angu-0,01 kuya kwangu-10) kanye namandla aphezulu kakhulu. Ikhiqizwa lapho ama-electron anamandla aphezulu eshayisana nethagethi yensimbi, ngokuzumayo anciphisa ijubane lawo futhi akhulule amandla ngesimo sama-photon e-X-ray.
Izici kanye Nezinhlobo
Kunezinhlobo ezimbili eziyinhloko ze-X-ray ezikhiqizwayo:
– Ama-X-ray ahlukile: Akhiqizwa lapho ama-electron egcwalisa ama-electron angekho emagobolondweni angaphakathi ama-athomu aqondiwe, akhiqize ama-photon anama-wavelength athile.
– Ama-X-ray e-Bremsstrahlung: Akhiqizwa lapho ama-electron encishiswa ijubane yinsimu kagesi ye-nucleus ye-athomu, okukhiqiza ububanzi obuqhubekayo bamaza e-X-ray.
Imiphumela kanye nezicelo
Ukutholakala kwe-X-ray kube nomthelela omkhulu emikhakheni eyahlukene, ikakhulukazi isayensi yezokwelapha kanye nezinto zokwakha. Kwezokwelapha, i-X-ray isetshenziselwa kokubili ukuxilonga kanye nokwelapha. I-X-ray radiography ivumela ukuthwebula izithombe zezakhiwo zangaphakathi zomzimba, kusiza odokotela ukuxilonga ukwaphuka kwamathambo, izimila, kanye nezinye izimo zezokwelapha ezahlukahlukene. Ukwelashwa ngemisebe kusebenzisa i-X-ray enamandla amakhulu ukubhubhisa amangqamuzana omdlavuza.
Kwisayensi yezinto ezibonakalayo, ama-X-ray asetshenziswa ku-X-ray crystallography ukuthola isakhiwo se-athomu kanye nesamangqamuzana samakristalu. Le ndlela iyithuluzi elibalulekile kumakhemikhali, i-biology, kanye nesayensi yezinto ezibonakalayo, okwenza kube lula ukuthola isakhiwo se-DNA nguRosalind Franklin, uJames Watson, noFrancis Crick.
Isiphetho
Umphumela we-photoelectric, umphumela we-Compton, kanye ne-X-rays kuyizinto ezijulile eziye zandisa ukuqonda kwethu uhlobo lokukhanya nezinto. Umphumela we-photoelectric ubonise uhlobo lwe-quantum lokukhanya, umphumela we-Compton uqinisekisile umfutho wama-photon, kanti ama-X-ray avule imihlaba emisha ekuthathweni kwezithombe nasekuhlaziyweni kwesakhiwo.
Ukutholakala nokuqonda lezi zimo kuholele ebuchwephesheni obungenakubalwa obushintshe imikhakha ehlukahlukene yesayensi nobunjiniyela. Kusukela ekusetshenzisweni kwezokwelapha kuya ocwaningweni lwesayensi, umphumela we-photoelectric, umphumela we-Compton, kanye ne-X-ray kuyaqhubeka nokudlala indima ebalulekile ekuthuthukisweni kobuchwepheshe nolwazi lwabantu.
