Gavin McCullagh wrote:
> On Thu, 15 May 2008, Michael Watterson wrote:
>>>> There are several ways to get one physically are really random. Thermal
>> noise is one of the simplest & cheapest. There is a reason why a
>> tungsten filament gives a CONTINUOUS spectrum (white noise = thermal
>> noise).
>>>> CONTINUOUS? Surely it's quantised if you look close enough at constant
> temperature? There are a finite number of electronic, rotational and
> vibrational modes so there should be a finite number of wavelengths.
>> Just curious,
> Gavin
>>If it was LED, Laser, EL panel, CRT, Gas Discharge etc, then yes, there
would be obvious discrete quantum energy levels (easily seen with a
prism). But it's thermal energy, thus I believe the light really can be
any wavelength, with the probability very much lower in UV and low
IR/EHF microwave. There is a distribution curve. The light energy is
I believe kinetic rather than excitation levels of electrons (Gas
Discharge, Phosphors (not just used CRT, but UV LED, CFL etc) , EL
panels, LEDs, OLEDS (which are more like low voltage EL than true LEDs).
--
Mike
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