{"id":361110,"date":"2017-02-03T03:00:00","date_gmt":"2017-02-03T00:00:00","guid":{"rendered":"https:\/\/www.fyysika.ee\/?guid=b8ccb4df86e128700da7643785ee55e0"},"modified":"2017-02-03T03:00:00","modified_gmt":"2017-02-03T00:00:00","slug":"measurement-of-the-ratio-h-e-with-a-photomultiplier-tube-and-a-set-of-leds-2","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=361110","title":{"rendered":"Measurement of the ratio h \/ e with a photomultiplier tube and a set of LEDs"},"content":{"rendered":"<p>We propose a laboratory experience aimed at undergraduate physics students to understand the main<br \/>\nfeatures of the photoelectric effect and to perform a measurement of the ratio h \/ e , where h is<br \/>\nPlanck\u2019s constant and e is the electron charge. The experience is based on the method developed by<br \/>\nMillikan for his measurements of the photoelectric effect in the years from 1912 to 1915. The<br \/>\nexperimental setup consists of a photomultiplier tube (PMT) equipped with a voltage divider properly<br \/>\nmodified to set variable retarding potentials between the photocathode and the first dynode, and a<br \/>\nset of LEDs emitting at different wavelengths. The photocathode is illuminated with the various LEDs<br \/>\nand, for each wavelength of the incident light, the output anode current is measured as a function<br \/>\nof the retarding potential applied between the cathode and the first dynode. From each measurement,<br \/>\na value of the stopping potential for the anode current is derived. Finally, th&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>We propose a laboratory experience aimed at undergraduate physics students to understand the main<br \/>\nfeatures of the photoelectric effect and to perform a measurement of the ratio h \/ e , where h is<br \/>\nPlanck\u2019s constant and e is the electron charge. The &#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[178],"tags":[],"class_list":{"0":"post-361110","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rss-fuusikaharidus","7":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/361110","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=361110"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/361110\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=361110"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=361110"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=361110"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}