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Announcement#1 2007-07-12 19:41:26
PhotonsI need clarification as to what is a photon and what is not a photon. I thought I understood that a photon is a unit of electromagnetic radiation having frequency and wavelength described by c= wavelengthXfrequency, c being the velocity of light. Visible light photons have wavelengths measured in Angstroms and frequencies measured in terraHz. Is electromagnetic radiation with a frequency of 10 Hz and a wavelength of approximately 9,314 miles also a photon? Such a photon is enormous to human beings with a maximum height of, say 7 feet or so, but very, very small compared to our galaxy. A half wavelength dipole for such a photon is impractical, of course, but isn't it still a photon? Offline #2 2007-07-12 19:49:49
Re: PhotonsThe thing with EM radiation, is that it can be thought of as a wave and a particle. When considered in particle form, it is a photon, but the larger the wave, the less it is generally accepted as a particle: it is so big, that it is though of as being altogether too wide to be a particle. On the other hand, smaller waves, such as UV, X-ray and gamma are almost always thought of as particles, as it makes it easier to understand - it all comes down to human nature and estimation as to why they are not called photons, but realy they are. Last edited by drowsy turtle (2007-07-12 19:50:32) A holy man will walk on water if he has faith enough, and idiot will drown. Paranoia-it's coming for you Offline #3 2007-11-25 20:33:12
Re: PhotonsA photon is the particle that carries the electromagnetic interaction - it is a guage boson. It has a mass of 0 and is often thought of as behaving like waves at a more everday scale. A photomultiplier detects photons and gives a click when it detects one. QED is the theory of lightand matter and describes photons. It stands for quantum electrodynamics. Richard Feynman has written a very good book on QED (a lecture) which isn't mathematical and decribes lots of phenomena such as light interfeerence. It is called QED and is published in many more scientific book shops. I found it very interesting. If you are interested in QED, this might be a good book for you. Last edited by Hoof47 (2007-11-25 20:35:56) Offline |
