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incident photons Physics Summarizing, we can say that two questions concerning this phenomenon troubled physicists: According to the classical electromagnetic theory, the kinetic energy of the ejected electrons depended on the light intensity, which was not observed. Furthermore, the electron ejection occurred immediately, regardless of the intensity of light; The effect should occur for any frequency, it would depend on the intensity of the electric field. Important consequences of the discovery The basic assumption of the classical theory is that light is an electromagnetic wave, its energy shouldbe distributed continuously in space. But that was not observed. The wave theory, at its peak,becomes impotent that phenomenon. So the physicist Einstein, in 1905, proposed an explanation for the photoelectric effect through the theory of quanta - a theory which conceived light as corpuscle and contradicted the idea of continuous power in space. According to Einstein, "the energy of the light wave is quantized into small packets, called photons. The energy of a photon is proportional to the frequency of the wave. What would be the consequences of Einstein's propositions? the light being a particle, the photon an increase in light intensity causes an increase in the potential and current is not cut; For an electron to be ejected it takes a photon collides with an electron and transfer all its energy to it. The transfer happens at the time of the collision the electron-photon (a single photon and electron), thus instantly. It is necessary that the photon has all the power needed. Increase the intensity does not good would therefore only increase the number of photons and not the number of ejected electrons. When trying to solve the problems raised by studies of the photoelectric effect, Einstein proposed the concept of quantization of light, inspired by the hypothesis of quantization of energy of Max Planck, which was formulated in the 1920s. The prediction of Einstein, who proposed that electromagnetic light propagated as though in "packages", the "light quanta" contradicted the predictions of classical physics. Not enough astonishment, the hypothesis was confirmed by the American physicist RA Millikan, in experiments conducted in 1914. electrons emitted Figure 9: The photoelectric effect This is the Einstein equation for the photoelectric effect: hf = K max + W Where: hf: is the photon energy (E = hf); max : is the maximum kinetic energy of the ejected electron, and, W represents the work required to pull an electron from the cathode surface. It's called work function. The nature of light and its properties
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incident fotoni Fizika Rezimirajući, možemo reći da su dva pitanja koja se odnose na ovaj fenomen uznemiri fizičara: Prema klasične elektromagnetske teorije, kinetička energija Izbačeni elektrona ovisi o intenzitetu svjetlosti, što nije bio primijećen. Nadalje, elektronska izbacivanje pojavio odmah, bez obzira na intenzitet svjetlosti; Učinak bi se trebalo dogoditi za bilo koju frekvenciju, to će ovisiti o intenzitetu električnog polja. Važno posljedice otkrića Osnovna pretpostavka od klasične teorije je da je svjetlost elektromagnetski val, njegova energija bi trebalabiti distribuirana kontinuirano u prostoru. Ali to nije primijetio. Valnoj teoriji, na svom vrhuncu,ona postaje nemoćna da je fenomen. Tako fizičar Einstein, 1905, predložio objašnjenje fotoelektričnog efektakvantna teorija - teorija koja je zamišljena svjetlost kao najsitniji i suprotstavljali ideju kontinuiranog vlast u prostoru. Prema Einsteinu, "energija svjetlosnog vala je kvantiziran u male pakete, nazvao fotoni. Energija fotona je proporcionalna frekvenciji vala. Što će biti posljedice Einsteinovih prijedloge? Svjetlo se čestica, foton povećanje intenziteta svjetla uzrokuje povećanje potencijala i struje ne siječe; Za elektron biti izbačen je potrebno foton sudari s elektronom i prijenos svu svoju energiju na to. Prijenos se događa u trenutku sudara elektron-foton (jedan foton i elektron), čime se odmah. Neophodno je da foton ima svu potrebnu snagu. Povećanje intenziteta ne good time bi samo povećati broj fotona, a ne broj mjesta izbacuje elektrone. Kada pokušavate riješiti probleme koje je studija fotoelektričnog efekta, Einstein je predložio koncept kvantizacije svjetlosti, inspiriran hipoteze kvantizacije energije Max Planck, koji je formulirao u 1920. Predviđanje Einsteina, koji je predložio da se elektromagnetsko svjetlo propagira kao da je u "paketima", "svjetlo kvanti" proturječio predviđanja klasičnoj fizici. Nije dovoljno zaprepaštenje, hipoteza je potvrđena od strane američkog fizičara RA Millikan, u pokusima provedenim u 1914. elektroni emitiraju Slika 9: fotoelektrični efekt Ovo je Einsteinova jednadžba za fotoelektrični efekt: Kmax = hf + W gdje je: HF: je foton energije (E = hf); Kmax: je maksimalna kinetička energija elektrona izbacile, i, W predstavlja radove potrebne za izvlačenje jedan elektron iz katodne površine. To se zove rad funkciju. Priroda svjetlosti i njegovih svojstava197