## Post-Assessment #31 [ENDORSED]

Alysia Garcia 1B
Posts: 40
Joined: Wed Feb 21, 2018 3:02 am

### Post-Assessment #31

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?

NabilaNizam-1K
Posts: 30
Joined: Fri Apr 06, 2018 11:04 am

### Re: Post-Assessment #31

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

Sam Metzger 1C
Posts: 25
Joined: Wed Apr 04, 2018 3:00 am

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

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.