Hi, I'm a newbie starting to study physics on my own (at a later age (45)). I've tried to find an answer to my question in this forum, the internet , books, etc... already. I'm reading Modern Physics, Tipler & LLewelyn. On p. 139 he presents a diagram illustrating Millikans experiment on work function (photoelectric effect). I've seen this same diagram on numerous other physics websites. (eg. http://hyperphysics.phy-astr.gsu.edu/hbase/mod2.html#c3 The treshold frequency of the incident light for an electron of the cathode to be ejected is -in this particular experiment- 43.9 *10^13 Hz. Now, this corresponds to an energy of E=hf = 43.9 * 10^13 s-1 * 4.136*10^-15 eV s = 1.82 eV Now my question: which element (metal) was this? Which material has a work function of 1.82 eV? I can't find any. Am I messing up on this? I'm really stuck. Can someone bring some clarity?