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Example 1.5 Part C in 6th Edition

Posted: Wed Oct 24, 2018 11:08 pm
by Dustin Shin 2I
In the textbook there is an example of analyzing the photoelectric effect. The first two parts I understand but I don't understand part C conceptually. The questions asks us: "To find the longest wavelength of radiation that is able to eject an electron." They go on to set Ek = 0 which I do not understand. Why would they set Ek = 0?

Re: Example 1.5 Part C in 6th Edition

Posted: Wed Oct 24, 2018 11:51 pm
by Jeffrey Xiao 4A
Since wavelength and frequency are inversely related, the longest wavelength possible corresponds to the lowest frequency possible to eject an electron, and since the equation for photoelectric effect is Ek=hv - work function, the lowest frequency that ejects an electron is when hv-work function=0 since Ephoton (hv) must be at least equal to work function to eject an electron, so Ek must be 0.