How do I calculate the frequency of an electron?

Question

mbaker5 · Answer

The question I need to answer is: Calculate the frequency of an electron traveling at 1.85 x 10^7 m/s. I thought the equation I would use is: $$v= \frac{ speed of light }{ wavelength }$$
But none of the multiple choice options match the answer I get when I use that equation.

jiteshmeghwal9 · Answer

wavelength is given ?

mbaker5 · Answer

Yes. The wavelength is: 1.85 x 10^7 m/s

jiteshmeghwal9 · Answer

It isnot wavelength. it is the velocity of electron

kainui · Answer

That's different, this is how you calculate the wavelength of light $c=\lambda \nu$

If you want to calculate the wavelength of an electron you must use $h=p \lambda$

h is Planck's constant, p is the momentum of the electron, which is $p=mv$ as usual, the mass of the electron times its velocity, and $\lambda$ is its wavelength.

It's probably better to memorize this pair of equations side by side since they are pretty similar (actually both comes out of solving the free particle Schrodinger equation but are basically observational facts):

$$E=h \nu = \hbar \omega$$$$p=h \tilde \nu = \hbar k$$

specifically, $\tilde \nu := \frac{1}{\lambda}$, if it looks a bit scary well I can't unscare you so... :P

mww · Answer

yes use the equations provided by Kainui
These are derived by equating 
$$E = h \nu = \frac{ hc }{ \lambda} = mc^2  \rightarrow mc = \frac{ h }{ \lambda } = p$$