Kinetic energy of an electron

1. May 13, 2008

Cowtipper

1. The problem statement, all variables and given/known data
If an electron has a measured wavelength of 0.850 x 10^-10 m, what is its kinetic energy?

2. Relevant equations
I'm not sure.

3. The attempt at a solution
And once again, I'm not too sure. Where do I start?

2. May 13, 2008

Redbelly98

Staff Emeritus
Find an equation in your textbook that deals with the wavelength of electrons or particles in general. That would be a start.

3. May 13, 2008

Cowtipper

Well, I've got this:

I'm not sure if it's one to use.

E = hc/$$\lambda$$

Similarly, I have this one:

K=1/2MV$$^{2}$$

However, I'm not sure where or how to use it in this instance, or if I have to use it at all.

Man, this stuff is getting tough. I was doing well there for a while too...

4. May 13, 2008

hage567

No, this equation will not work. Look back in your notes and try to figure out why.

Look up "de Broglie wavelength."

5. May 13, 2008

Cowtipper

Aha! That is all I needed to know.

Thanks a lot!