How to Calculate the Maximum Energy of Ejected Electrons?

[Panic Attack]

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)

 

[Panic Attack]

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?

 

[john54]

If it is not too late...

The max k.e. should be 8 eV

 

[Panic Attack]

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?

 

[Redbelly98]

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.)

 

[Panic Attack]

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... :)