How to calculate wavelength electron given speed

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SUMMARY

The discussion focuses on calculating the wavelength of an electron given its speed using relevant physics equations. The user initially applies the equations for kinetic energy and photon energy, leading to confusion regarding the units and the application of de Broglie's formula for matter waves. The correct approach involves using de Broglie's wavelength formula, which is essential for particles like electrons, rather than photon equations. The user resolves their confusion with assistance from the forum, confirming the importance of using the appropriate formulas for different types of waves.

PREREQUISITES
  • Understanding of kinetic energy formula (1/2 mv^2)
  • Familiarity with Planck's equation (E = hf)
  • Knowledge of the speed of light and its relation to frequency and wavelength (c = f * wavelength)
  • Comprehension of de Broglie's wavelength formula for matter waves
NEXT STEPS
  • Study de Broglie's wavelength formula for particles
  • Learn about the differences between matter waves and photon waves
  • Explore the implications of quantum mechanics on particle behavior
  • Investigate the relationship between energy, frequency, and wavelength in various contexts
USEFUL FOR

Students in physics, particularly those studying quantum mechanics, as well as educators and anyone interested in the wave-particle duality of matter.

Adam Rabe
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Homework Statement


Unit conversion where did i go wrong.PNG

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
 
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Adam Rabe said:

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.
Adam Rabe said:
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?
 
ehild said:
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
 

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