Calculate the threshold wavelength of the metal.

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Offline Chikis

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Caesium metal of work function [tex]2.0 eV[/tex] is illuminated with radiations of wavelength [tex]5.0\times10^{-7}m[/tex]. Calculate the:
(i)threshold wavelength of the metal;
(ii)maxium energy of liberated elecrons.
[tex][h=6.6\times10^{-34} Js; IeV=1.6\times10^{-19} J; c=3.0\times10^8 ms^{-1}][/tex]

Since threshold frequency and threshold wavelenght are not the same, am confused of the formula to use.
What is the best formula to use? Should I use [tex]\omega=hfo[/tex] or should use
[tex]E=\frac{hc}{\lambda}[/tex]

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Offline evan_au

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Re: Calculate the threshold wavelength of the metal.
« Reply #1 on: 21/07/2014 10:20:49 »
Would it make more sense if you used the definition that Frequency f = c/λ = (Speed of light)/wavelength.

Perhaps those equations are equivalent?