How to Calculate the Maximum Energy of Ejected Electrons?

Panic Attack
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Homework Statement


What is the maximum energy of the ejected electrons? When the radiation wavelength is 100 nm, and the stopping potential of the metal is 8.


Homework Equations


KE = hc/wavelenght - Wo


The Attempt at a Solution


I found the work function and the cut off wavelength to be the following but I can't figure out the max energy...

KE = hc/wavelenght - Wo

Wo = work function = { (6.63 *10^-34)(3*10^8) / (100 *10^9) } - (1.6*10^-19)(8)
Fo = cut off frequency = Wo / (6.63 *10^-34)
 
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I think I have an answer, but I don't know if it is right...

E = Wo + KE, where Wo = 1.225*10^-19, in which I solved for
E = hc/lambda = 6.62*10^-34 * 3*10^8 / 150*10^-19 = 1.324*10^-18

E = Wo + KE
1.324*10^-18 = 1.225*10^-19 + KE

KE = 1.2015*10^-19?

Can someone tell me if this is right?
 
If it is not too late...

The max k.e. should be 8 eV
 
john54 said:
If it is not too late...

The max k.e. should be 8 eV

It's never too late. I think I got this problem wrong then. Can you explain how you got 8?
 
Panic Attack said:
KE = hc/wavelenght - Wo
You are given wavelength and Wo in the problem statement, and are asked to calculate KE. You seem to be over-complicating things. (The answer is not 8 eV, by the way.)
 
Redbelly98 said:
You are given wavelength and Wo in the problem statement, and are asked to calculate KE. You seem to be over-complicating things. (The answer is not 8 eV, by the way.)

teheheh... I got it right den... :)
 

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