Foton
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Elektromagnetisk stråling (inklusiv lys og radiobølger) kan betragtes som enten et elektromagnetisk bølgefænomen, eller et partikelfænomen. Anlægger man sidstnævnte betragtning, består lyset af en "strøm" af partikler, og disse partikler kaldes for fotoner. Set under den første synsvinkel er en foton et energikvant med energien 
givet ved
hvor 
er Plancks konstant og 
er bølgens frekvens. Lysets bølgelængde i vakuum 
er omvendt proportional med fotonenergien :
hvor 
er lysets hastighed. Eksempelvis har synligt lys en bølgelængde mellem 400 nm og 700 nm.
[redigér] Se også
| Det elektromagnetiske spektrum (lave til høje frekvenser): |
| Lave frekvenser: Radiobølger |
| ELF | VF | VLF | LF (Langbølgebåndet) | MF (Mellembølgebåndet) | Kortbølgebåndet (HF) | VHF (TV via VHF bånd I, FM via VHF bånd II, TV via VHF bånd III) | UHF (TV via UHF bånd V, TV via UHF bånd IV) | SHF (DBS) | EHF |
| Høje frekvenser: Lys og Stråling |
| IR (FIR, IIR, MIR, NIR) | Synligt lys | UV (NUV, EUV) | SX | HX | γ |
| Relaterede emner: |
| Sollys | Termisk energi | Fotosyntese | Solenergi | Solcelle | Solvarme | Solen | Radioantenne | Radiofoni |
[redigér] Eksterne henvisninger
- Webarchive backup: En lyspartikel med identitetsproblemer (humoristisk tegning)
- Number 523 #2, February 1, 2001, AIP: How Light Gets Through Tiny Holes Citat: "...Now, two research collaborations independently explain the results by showing that plasmons (themselves collective objects) and the photons of light form a composite object, known as a "surface plasmon polariton."..."
- 'Energy-sucking' Radio Antennas, N. Tesla's Power Receiver Citat: "...The truth is quite strange...By manipulating the EM fields, we can force an electrically-small receiving antenna to behave as if it was very, VERY large...In theory a tiny loop antenna can work as well as a longwire 1/2-wave antenna which is 10KM long...The energy doesn't vanish, instead it ends up INSIDE the atom. By resonantly creating an "anti-wave", the tiny atom has "sucked energy" out of the enormously long light waves as they go by...When all is said and done, our oscillating coil has absorbed half of the incoming EM energy and re-emitted (or "scattered") the rest..."
- C. F. Bohren, "How can a particle absorb more than the light incident on it?", Am J Phys, 51 #4, pp323 Apr 1983 Citat: "...A particle can indeed absorb more than the light incident on it...In the former, strong absorption is associated with excitation of surfaces plasmons; in the latter it is associated with excitation of surface phonons. In both instances, the target area a particle presents to incident light can be much greater than its geometrical cross-sectional area...."
- Regeneration revisited. The Tesla Connection by Gary L. Peterson Citat: "...So it may be said that Tesla anticipated the technique of regenerative feedback to increase detector sensitivity...A detailed description of how the negative resistance, negative inductance circuit works, including a differential form of the active antenna circuit and other pertinent information, can be found in U.S. Patent No. 5,296,866, Mar. 22, 199..."
