# Homework Help: Ekmax and the Work function

1. Dec 6, 2009

### StephenP91

Much easier if I just write it without the given templates.

Well, I am not exactly the good at Physics, so I've decided to ask people that are good at it.

I know Ekmax = hf - work function. I am just wondering what could prevent the electron from attaining it's maximum kinetic energy.

Oh, wait. Is it just that Ekmax is for the electrons on the surface and not the ones further in the metal? So the electrons further in have a kinetic energy of less than Ekmax?

Thank you,
Stephen.

Last edited: Dec 6, 2009
2. Dec 6, 2009

### ehild

You are almost on the right track. The electrons in the metal can have different potential energies. It is said that they are in a potential well, and those with the highest allowed energy can escape if they get the energy of the work function. The others need more. When an electron interacts with a photon and gains all its energy, part of this energy will be consumed to lift the electron to the top of the potential well, the other part is for overcoming the work function and the remaining part is the kinetic energy.

ehild