Threshold Frequency vs Work Function
Kev ua haujlwm thiab qhov pib zaus yog ob nqe lus cuam tshuam nrog cov nyhuv photoelectric. Cov nyhuv photoelectric yog ib qho kev sim dav siv los ua kom pom qhov xwm txheej ntawm nthwv dej. Hauv tsab xov xwm no, peb yuav tham txog dab tsi photoelectric effect yog dab tsi, kev ua haujlwm thiab qhov pib zaus yog dab tsi, lawv daim ntawv thov, qhov zoo sib xws thiab qhov sib txawv ntawm kev ua haujlwm thiab qhov pib zaus.
qhov pib zaus yog dab tsi?
Yuav kom nkag siab txog lub tswv yim ntawm qhov pib zaus, ib tus yuav tsum xub nkag siab txog cov nyhuv photoelectric. Cov nyhuv photoelectric yog txheej txheem ntawm ejection ntawm ib qho hluav taws xob los ntawm cov hlau nyob rau hauv cov ntaub ntawv ntawm qhov teeb meem electromagnetic hluav taws xob. Cov nyhuv photoelectric yog thawj zaug tau piav qhia los ntawm Albert Einstein. Lub yoj txoj kev xav ntawm lub teeb tsis tau piav qhia txog feem ntau ntawm cov kev soj ntsuam ntawm cov nyhuv photoelectric. Muaj qhov pib zaus rau qhov xwm txheej nthwv dej. Qhov no qhia tau hais tias txawm tias qhov kub npaum li cas ntawm electromagnetic tsis yog electrons yuav tsis raug tshem tawm tshwj tsis yog nws muaj qhov yuav tsum tau ua. Lub sij hawm ncua ntawm qhov tshwm sim ntawm lub teeb thiab ejection ntawm electrons yog hais txog ib txhiab ntawm tus nqi xam los ntawm yoj txoj kev xav. Thaum lub teeb tshaj qhov pib zaus raug tsim, tus naj npawb ntawm emitted electrons nyob ntawm qhov siv ntawm lub teeb. Qhov siab tshaj plaws kinetic zog ntawm ejected electrons nyob ntawm qhov zaus ntawm qhov teeb meem teeb. Qhov no coj mus rau qhov xaus ntawm photon txoj kev xav ntawm lub teeb. Qhov no txhais tau hais tias lub teeb coj li cov khoom thaum cuam tshuam nrog cov teeb meem. Lub teeb los ua cov pob ntawv me me ntawm lub zog hu ua photons. Lub zog ntawm photon tsuas yog nyob ntawm qhov zaus ntawm photon. Qhov no tuaj yeem tau txais los ntawm cov qauv E=h f, qhov twg E yog lub zog ntawm photon, h yog Plank tas li, thiab f yog qhov zaus ntawm nthwv dej. Txhua qhov system tuaj yeem nqus lossis tawm tsuas yog qee qhov tshwj xeeb ntawm lub zog. Cov kev soj ntsuam pom tau hais tias cov electron yuav nqus cov photon tsuas yog tias lub zog ntawm photon txaus coj cov electron mus rau lub xeev ruaj khov. Qhov chaw pib zaus yog txhais los ntawm lo lus ft
Kev Ua Haujlwm yog dab tsi?
Kev ua haujlwm ntawm cov hlau yog lub zog sib haum rau qhov pib zaus ntawm cov hlau. Txoj haujlwm ua haujlwm feem ntau yog txhais los ntawm Greek tsab ntawv φ. Albert Einstein siv cov haujlwm ua haujlwm ntawm cov hlau los piav txog cov nyhuv photoelectric. Qhov siab tshaj plaws kinetic zog ntawm ejected electrons nyob ntawm qhov zaus ntawm qhov teeb meem photon thiab kev ua haujlwm. K. E.max=hf – φ. Kev ua haujlwm ntawm cov hlau tuaj yeem txhais tau tias yog qhov tsawg kawg nkaus daim ntawv cog lus lub zog lossis lub zog ntawm cov khoom siv hluav taws xob. Yog tias lub zog ntawm qhov xwm txheej photons sib npaug rau kev ua haujlwm, lub zog kinetic ntawm cov hluav taws xob tso tawm yuav yog xoom.
Dab tsi yog qhov txawv ntawm Kev Ua Haujlwm Kev Ua Haujlwm thiab Kev Ua Haujlwm zaus?
• Kev ua haujlwm yog ntsuas hauv joules lossis electron volts, tab sis qhov pib zaus yog ntsuas hauv hertz.
• Kev ua haujlwm tuaj yeem siv ncaj qha rau Einstein kab zauv ntawm cov nyhuv photoelectric. Txhawm rau siv qhov zaus ntawm qhov pib, qhov zaus yuav tsum muab sib npaug los ntawm cov phiaj xwm tas li txhawm rau kom tau txais lub zog sib xws.
