How to calculate wavelength electron given speed

[Adam Rabe]

Homework Statement

Homework Equations

1/2 mv^2
E = hf
c = f (wavelength)

The Attempt at a Solution

0.5 * (9.109 * 10^-31) * (6 * 10^4)^2 = energy
energy = hf => f = energy/(6.626*10^-34) = 2.47 * 10^12
wavelength (m) = (speed of light) / frequency
wavelength (m) * (1*10^9) = 121235.4

Answer is 12. What gives guys I am 4 decimal places too high is there some unit for any of the equations I am not getting?
Any help is greatly appreciated.
Adam

 

[ehild]

Homework Statement

View attachment 204156

Homework Equations

1/2 mv^2
E = hf

That formula is valid for photons. For matter waves, use de Broglie's formula for the wavelength.

Answer is 12. What gives guys I am 4 decimal places too high is there some unit for any of the equations I am not getting?
Any help is greatly appreciated.
Adam

12 in what units?

 

[Adam Rabe]

That formula is valid for photons. For matter waves, use de Broglie's formula for the wavelength.

12 in what units?

omg i got it now. thanks a lot friend