{"id":1009,"date":"2010-12-15T02:57:30","date_gmt":"2010-12-15T02:57:30","guid":{"rendered":"http:\/\/labrigger.com\/blog\/?p=1009"},"modified":"2010-12-16T09:29:51","modified_gmt":"2010-12-16T09:29:51","slug":"watts-per-photon","status":"publish","type":"post","link":"http:\/\/labrigger.com\/blog\/2010\/12\/15\/watts-per-photon\/","title":{"rendered":"Watts per photon"},"content":{"rendered":"<p align=\"center\"><a href=\"http:\/\/history.fnal.gov\/visitors.html\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/labrigger.com\/blog\/wp-content\/uploads\/2010\/12\/bubble_fermi.jpg\" alt=\"\" title=\"A nice old image from a bubble chamber at Fermilab. Studying neutrinos. Dated 1976.\" width=\"600\" height=\"419\" class=\"aligncenter size-full wp-image-1010\" srcset=\"http:\/\/labrigger.com\/blog\/wp-content\/uploads\/2010\/12\/bubble_fermi.jpg 600w, http:\/\/labrigger.com\/blog\/wp-content\/uploads\/2010\/12\/bubble_fermi-300x209.jpg 300w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><\/a><\/p>\n<p>Fun conversion of the day: photon count to watts. This is high school physics, but it&#8217;s a good reminder of scale.<\/p>\n<p>Let&#8217;s take a decent flux, say 50 million green (520 nm) photons per second. The energy (units = J) is equal to the frequency (units = 1\/s) times Planck&#8217;s constant (units = J*s). The wattage is the energy per unit time (watts = J\/s).<\/p>\n<p>Wattage of flux = 50e6 green photons per second * (c \/ 520e-9) * 6.63e-34<br \/>\n(c = speed of light = 3e8 m\/s)<\/p>\n<p>= 1.9e-11 watts<\/p>\n<p>So it&#8217;s clear why <em>thorough<\/em> lightproofing is necessary. There are hundreds of watts of overhead lighting. That&#8217;s 13 orders of magnitude more light than you&#8217;re trying to measure. And if you&#8217;re working with dim samples, the fluxes can be orders of magnitude less than assumed in this calculation.<\/p>\n<p>(Hat tip to CW.)<\/p>\n","protected":false},"excerpt":{"rendered":"<p align=\"center\"><a href=\"http:\/\/history.fnal.gov\/visitors.html\"><\/a><\/p>\n<p>Fun conversion of the day: photon count to watts. This is high school physics, but it&#8217;s a good reminder of&#8230;<\/p>\n<div class=\"read-more\"><a href=\"http:\/\/labrigger.com\/blog\/2010\/12\/15\/watts-per-photon\/\">Read More<\/a><\/div><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1009","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/1009","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/comments?post=1009"}],"version-history":[{"count":8,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/1009\/revisions"}],"predecessor-version":[{"id":1017,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/1009\/revisions\/1017"}],"wp:attachment":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/media?parent=1009"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/categories?post=1009"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/tags?post=1009"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}