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### Post-Assessment #31

Posted: Fri Apr 20, 2018 12:49 pm
If 3.607 x 10-19 J is required to remove an electron with zero kinetic energy from a metal surface, what would be the longest wavelength light that could do this?
I understand that you have to use Ek= Energy of incoming photon - work function, but what would I use for the kinetic energy?

### Re: Post-Assessment #31

Posted: Fri Apr 20, 2018 1:34 pm
If you are calculating the kinetic energy of the ejected electron, you can use the equation $E= \frac{1}{2} mv^2$
where m=mass of an electron and v=velocity of the electron after it's ejected

### Re: Post-Assessment #31  [ENDORSED]

Posted: Sat Apr 21, 2018 3:54 pm
For this problem, the kinetic energy is zero so the energy of the photon would equal the work energy. From here, we can find the wavelength by using the equations E=hv and c=v(wavelength) and solve for the wavelength.