# Kinetic energy of an electron

## Homework Statement

If an electron has a measured wavelength of 0.850 x 10^-10 m, what is its kinetic energy?

I'm not sure.

## The Attempt at a Solution

And once again, I'm not too sure. Where do I start?

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Redbelly98
Staff Emeritus
Homework Helper
Find an equation in your textbook that deals with the wavelength of electrons or particles in general. That would be a start.

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...

hage567
Homework Helper
Well, I've got this:

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

E = hc/$$\lambda$$
No, this equation will not work. Look back in your notes and try to figure out why.

Look up "de Broglie wavelength."

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

Look up "de Broglie wavelength."
Aha! That is all I needed to know.

Thanks a lot!