De Broglie Wavelength/Electron momentum

In summary, the conversation discusses the concept of momentum in quantum physics and its relation to kinetic energy. The equation p=h/wavelength is mentioned and it is clarified that this is referring to linear momentum, not angular momentum. The relation between momentum and kinetic energy is stated to be the same as in classical physics. The conversion of eV to SI units is also mentioned and the equation EK = p^2/(2m) is recommended to be memorized. The conversation ends with the discussion of converting units for a specific problem.
  • #1
DiamondV
103
0

Homework Statement


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Homework Equations


Einsteins photon momentum: p=h/wavelength (rearrange to get de broglie wavelength)

The Attempt at a Solution


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I am quite new to all this quantum physics stuff. First of all where is the momentum of the electron reffering to its angular momentum when it is orbiting? Can anyone explain this further to me. I think I need an equation here that relates the momentum to kinetic energy, I can't find anything like that.
 
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  • #2
DiamondV said:
First of all where is the momentum of the electron reffering to its angular momentum when it is orbiting?
No, this is linear momentum. You can simply imagine an electron traveling in a straight line.

DiamondV said:
I think I need an equation here that relates the momentum to kinetic energy, I can't find anything like that.
The relation is the same as in classical physics.
 
  • #3
DrClaude said:
No, this is linear momentum. You can simply imagine an electron traveling in a straight line.The relation is the same as in classical physics.

Doesn't Einsteins relativity apply with electrons kinetic energy? I mean I don't think we can use KE=(1/2)mv^2
 
  • #4
DrClaude said:
No, this is linear momentum. You can simply imagine an electron traveling in a straight line.The relation is the same as in classical physics.

Okay. I seem to have gotten somewhere further now. But my answer is incorrect, not too sure what to do with units. What is eV actually equal to in SI units?
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  • #5
DiamondV said:
Doesn't Einsteins relativity apply with electrons kinetic energy? I mean I don't think we can use KE=(1/2)mv^2
What is the velocity corresponding to the momentum you calculated? Is it relativistic?
DiamondV said:
Okay. I seem to have gotten somewhere further now. But my answer is incorrect, not too sure what to do with units.
First, you should write the units in the calculation you made, to make sure everything is correct.

DiamondV said:
What is eV actually equal to in SI units?
1 eV = 1.60218×10-19 (that wasn't hard to find with Google :wink:)

By the way, you should commit to memory that ##E_K = p^2/(2m)##. It comes up all the time in quantum mechanics (and classical mechanics, for that matter).
 
  • #6
DrClaude said:
What is the velocity corresponding to the momentum you calculated? Is it relativistic?
First, you should write the units in the calculation you made, to make sure everything is correct.1 eV = 1.60218×10-19 (that wasn't hard to find with Google :wink:)

By the way, you should commit to memory that ##E_K = p^2/(2m)##. It comes up all the time in quantum mechanics (and classical mechanics, for that matter).

Alright. So I checked the units it and I am getting Joules for my kinetic energy which seems correct. My answer is wrong though not sure why?

EDIT: I just realized its asking for answer in microeV, so ill just convert it. thanks for the help
 

1. What is the de Broglie wavelength?

The de Broglie wavelength is a concept in quantum mechanics that describes the wavelength of a particle, such as an electron, based on its momentum. It is named after French physicist Louis de Broglie who first proposed the idea in 1924.

2. How is the de Broglie wavelength calculated?

The de Broglie wavelength is calculated using the formula λ = h/mv, where λ is the wavelength, h is Planck's constant, m is the mass of the particle, and v is the velocity of the particle. This formula is known as the de Broglie equation.

3. What is the significance of the de Broglie wavelength?

The de Broglie wavelength is significant because it demonstrates the wave-particle duality of matter. It suggests that all particles, including electrons, have both wave-like and particle-like properties.

4. How does the de Broglie wavelength affect the behavior of electrons?

The de Broglie wavelength affects the behavior of electrons in that it determines the probability of finding an electron at a certain location. This is known as the wave function of the electron and is described by Schrödinger's equation.

5. Can the de Broglie wavelength be observed?

No, the de Broglie wavelength itself cannot be observed. However, its effects can be observed through experiments such as the double-slit experiment, where the wave-like behavior of particles, including electrons, can be observed.

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