### module question 28 a

Posted:

**Sun Oct 21, 2018 11:36 pm**For this question, "Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 10^5 m.s-1. The work function for sodium is 150.6 kJ.mol-1. What is the kinetic energy of the ejected electron?" I know that E(photon)-E(energy remove e-)=Kinetic energy of the electron.

h*frequency(v)-work function=1/2MeVe^2. I plugged in h=6.626 x 10^-34 Js and the given work function 150.6 kJ.mol-1. I also know that the velocity is 6.61 x 10^5 m.s-1. I am confused as where we get the mass of the electron from will it be given? And also once I do have that do I just ignore the rest of the equation and only use Ek=1/2Me*Ve^2? If so, when would I use the given work function then?

h*frequency(v)-work function=1/2MeVe^2. I plugged in h=6.626 x 10^-34 Js and the given work function 150.6 kJ.mol-1. I also know that the velocity is 6.61 x 10^5 m.s-1. I am confused as where we get the mass of the electron from will it be given? And also once I do have that do I just ignore the rest of the equation and only use Ek=1/2Me*Ve^2? If so, when would I use the given work function then?