urgent sur UV

[invite38de836e]

est ce que quelqu'un sait quel est l'action de l'UV sur le chlorure d'argent?
quel a été la découverte de wilhelm ritter??
SVP c'est urgent
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[philou21]

Ritter is best known for his discovery of the ultraviolet spectrum in 1801. It was the time where the astrophysicist Sir Herschel discovered radiation beyond the red spectral range, the infrared (IR) light. Strongly influenced by the philosophical views of Romanticism and Naturphilosophie, he believed in the principle of polarity in nature, and after Herschel’s discovery of infrared rediation, he hypothesized a possible polarity in the spectrum and successfully looked for invisible radiation beyond the violet. In 1801 he was experimenting with silver chloride (AgCl). This chemical is decomposed by light, liberating silver which makes the colourless substance turn black. This reaction is the basis of pre-digital photography. In chemistry at that time there was a rumour that blue light was more efficient at initiating chemical change than red light. Ritter tried to measure the speed at which silver chloride broke down with different colours. He proved that blue light was indeed more efficient that red light. He was amazed, however, that the most vigorous reactions took place in the region beyond the violet where nothing could be seen. This new radiation was originally called Chemical Rays but is now called Ultra Violet (beyond the violet). The reception of this discovery was hindered by Ritter’s abstruse style and his tendency to mix speculations with scientific observations. His discovery of ultraviolet radiation was independent of Wollaston's discovery, also in 1802. Ritter also made contributions to spectroscopy.

in http://www.geocities.com/bioelectrochemistry/ritter.htm

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[invite38de836e]

j'ai toujours pas compris qeul est leffet exact des UV sur AgCl
Vous pourriez expliquer plus svp

[philou21]

j'ai toujours pas compris qeul est leffet exact des UV sur AgCl
Vous pourriez expliquer plus svp

Sans doute le même effet que la lumière visible.
Fais des recherches sur la photographie argentique...
L'article de wikipedia explique assez bien.

[A voir en vidéo sur Futura]

[invite38de836e]

merci pour linfo mais s'il ya quelqu'un d'autre qui a des informations qu'il les passe svp

[invite2f719841]

précipitation
coloration noir

[invite38de836e]

comment ça précipitation et coloration noir? j'ai pas compris

[dggchim]

bonjour,

Voici quelques info:
http://forums.futura-sciences.com/ch...e-dargent.html

http://noelecocq.ovh.org/?p=5

http://www.americanchemistry.com/s_c...22&CTYPEID=113

[invite38de836e]

Merci pour les liens mais ça ne m'aide toujours pas parceque je veux savoir l'action exact des UV sur AgCl