# What is Debroglie wavelength: Definition and 31 Discussions

Matter waves are a central part of the theory of quantum mechanics, being an example of wave–particle duality. All matter exhibits wave-like behavior. For example, a beam of electrons can be diffracted just like a beam of light or a water wave. In most cases, however, the wavelength is too small to have a practical impact on day-to-day activities.
The concept that matter behaves like a wave was proposed by French physicist Louis de Broglie () in 1924. It is also referred to as the de Broglie hypothesis. Matter waves are referred to as de Broglie waves.
The de Broglie wavelength is the wavelength, λ, associated with a massive particle (i.e., a particle with mass, as opposed to a massless particle) and is related to its momentum, p, through the Planck constant, h:

λ
=

h
p

=

h

m
v

.

{\displaystyle \lambda ={\frac {h}{p}}={\frac {h}{mv}}.}
Wave-like behavior of matter was first experimentally demonstrated by George Paget Thomson's thin metal diffraction experiment, and independently in the Davisson–Germer experiment, both using electrons; and it has also been confirmed for other elementary particles, neutral atoms and even molecules.

View More On Wikipedia.org
1. ### Wavelength = deBroglie Wavelength?

Homework Statement Find the retarding potential required to stop electron of de-broglie wavelength 0.5 nm Homework Equations 1)de-broglie wavelenght=h/momentum 2)eV=KE of electron 3)KE=p^2/2m The Attempt at a Solution Using the above three relations is giving me an incorrect answer for V...
2. ### I De Broglie relation using four momentum in particle physics

In particle phyisics four-momentum is used and De Broglie relation is used to understand what lenghts can be "seen" in an experiment. Here (page 6) https://people.phys.ethz.ch/~pheno/PPP/PPP2.pdf it is claimed Where ##Q^2## is not actually "momentum" but its the square of the four momentum...
3. ### I Energy-momentum formula and deBroglie wavelength

Hi everyone, Im a little bit confused about deBroglies procedure on introducing his famous Matterwave formula. People already knew that the wavelength of the light was equal to Lambda = h/p. The term p comes from the energy-momentum formula; for the light the restmass = 0 so E =pc etc. As...
4. ### I DeBroglie wavelength & particle-wave duality

We are told to exorcise wave-particle duality because it belongs to the past, in fact prior to 1927. So it’s acceptable to believe matter is neither wave nor particle. But in exorcising wave-particle duality. Why does the deBroglie relationship of momentum being inversely proportional to...
5. ### Why is deBroglie λ for electrons the same as λ for photons?

Hi, I got the following question in my textbook: [translated]"Compare the wavelength of a photon and an electron where the photon and the electron have the same momentum". My thinking is the following: Firstly, pp (photon) = pe (electron). My textbook briefly mentions the extention of the...
6. ### DeBroglie wavelength based on kinetic energy

Homework Statement I am working on a problem similar to this one: In this solution, I do not understand what mc is, can someone explain? Also, would I follow the same type of steps if I have the kinetic energy of a photon and I need it's wavelength? Homework EquationsThe Attempt at a Solution
7. ### I Odd use of terms (“stationary stochastic process”., etc.)

I am trying to make sense of a Russian author’s use of terms (I have to translate his article). I have three questions, but please don't think you need to answer all three before answering. Thanks for any insights! [1] He uses the term “probability density distribution” ρ(ξ) of a stationary...
8. ### A De-Broglie's Fictitious wave

I read through DeBroglie's original paper - and also a modern explanation on the same (attached). The first contradiction that DeBroglie arrives at is simple enough - he considers the 'wave-particle' as observed from a stationary frame - and from a moving frame. The 'inner frequency' of the...
9. ### B Electron Diffraction and the DeBroglie Wavelength

I've been reading up on electron diffraction for electron microscopy, and I have been trying to understand the proof for the wavelength of an electron in a tunneling electron microscope. The proof I have been trying to emulate begins as follows: It then says that I must account for...
10. ### B How does electron microscopy exploit wave/particle duality?

I have been researching wave/particle duality, and I have trouble comprehending how electron microscopy actually exploits wave/particle duality to operate. From Wikipedia, " Wave–particle duality is exploited in electron microscopy, where the small wavelengths associated with the electron can...
11. ### Finding the deBroglie wavelength: conceptual issue

Hello all! I am new to this forum, though I have been lurking for a long time. I intend to fill out my profile and introduce myself, but finals leave me with little time to spare at the moment. I have this final next week and would like to sort this out beforehand, hence the hasty post! Thank...
12. ### B DeBroglie Wavelength with Relativistic Electron

I am trying to find the DeBroglie wavelength of an electron moving at .8c. I have never learned special relativity but I believe the momentum is affected (mass change). I used the formula p= (mv)/(1-v^2/c^2) and got a momentum of p = 2.733 E-22 and a wavelength of lamda = 2.4149 E-12. Did I...
13. ### DeBroglie wavelength of Proton in H atom

How would one calculate the de Broglie wavelength of the proton in the hydrogen atom as the electron and proton pirouette around their common center of mass, for the lowest orbital? I believe the center-of-mass of the system would actually be inside the proton due to the great differential in...
14. ### Why do all particles have a wavelength?

So for my AS specification I need to know how to use the debroile wavelength equation which is fair enough and easy. I was wondering if anyone could tell me why do all particles have a wavelength or wave function? Or even like a tennis ball? Thanks, PS: I know it's a weird question...
15. ### DeBroglie wavelength in infinite potential well

nvm i figured it out. it was not in reference to n=4. equation used would be wavelength = 2L/n Homework Statement An electron is in an infinite potential well of width L. Which is not an allowed deBroglie wavelength for the electron to have when n=4? wavelength(k) = 3L, 2L, L/2, or L/3Homework...
16. ### Debroglie Wavelength: λ & v Proportional?

According to Debroglie Eq λ=h/mv λ and v inversely proportional to each other.But according to eq v=f*λ they seem to be directly proportional.So what is the actual dependence of lambda on v?
17. ### DeBroglie Wavelength: Proton at Room Temp Scattering Behavior

A proton at room temperature with an energy of 0.025eV has a deBroglie wavelength of about 1A (1E-10 meters). If we shoot two proton beams at each other with is low energy and large wavelength what happens? Do they scatter as if they are small hard particles of size about 1 fermi (1E-15 meters)...
18. ### DeBroglie wavelength, kE to (p) conversion?

I have a relatively simple question. I should know this, but... I need to solve for the deBroglie wavelength when only the kinetic energy is known. Shouldn't I be able to convert kE to momentum (p), when the object does not have a known velocity or mass...? Much thanks... JD
19. ### DeBroglie wavelength and nucleon velocity

Homework Statement Atomic nucleus consists of nucleons. What velocity (order of magnitude estimate) will a nucleon have inside a nucleus? Homework Equations \lambda = h/mv v = h/m\lambda The Attempt at a Solution The wavelength of a nucleus is on the order of 10^-15/m...
20. ### Calculate DeBroglie Wavelength & Kinetic Energy of Electron

Homework Statement What is the DeBroglie wavelength of an electron whose energy is (a) 1.0eV (b) 100eV? What is the kinetic energy in eV of an electron whose DeBroglie wavelength is that of visible red light at 650nm? Homework Equations λ=h/p = h/mv h = Planck's constant...
21. ### DeBroglie Wavelength: Solving for Electrons in Relativity

Homework Statement An electron of charge e and rest mass m0 is accelerated to relativistic speeds by a potential V. Show that the deBroglie wavelength is given by the expression lambda= h(2m0eV)-1/2 (1+eV/2m0c2)-1/2 The Attempt at a Solution eV = gamma m0c2 equation one p = gamma...
22. ### Debroglie Wavelength Homework: Proton and Alpha Particle Ratio

Homework Statement The momentum of a proton and an alpha particle are equal. The mass of alpha particle is 4 times the mass of proton. The ratio of wavelength associated with them is ---- Homework Equations \lambda = h / p The Attempt at a Solution if the momentum are equal then...
23. ### DeBroglie wavelength for particle at rest

lambda = h/mv v -> 0 means lambda is -> infinite? So if I have an old pickup truck that moves really slow, its matter wave is huge, right?? So it's now a wave and not a particle?
24. ### DeBroglie Wavelength Comparison

Homework Statement Compare the deBroglie wavelength for an electron in the n=6 orbit of He+ compared to the n=2 orbit. Is the deBroglie wavelength the same, smaller, or larger? Derive this. Homework Equations Quantization of Paths of Electrons: 2 pi r = n (lambda) Bohr Radius: rn=n2 aB The...
25. ### Electron and deBroglie wavelength

Homework Statement An electron moves in the x direction with the de Broglie wavelength 10^-8 cm. a) What is the energy of the electron in (eV)? b) What is the time-independent wavefunction of the electron? Solution? a) We have p = h/2pi * k = h/2pi * 2pi / lambda. So, p = h /...
26. ### DeBroglie wavelength / particle phys

Would anybody be able to advise how I would approach the following question? I know the deBroglie wavelength is h/p, but I'm unsure how to calculate p based on the kinetic/total energy...
27. ### Find de Broglie Wavelength of 7.0 eV Electron

Homework Statement Find the de Broglie wavelength of a 7.0 eV electron.Homework Equations de Broglie wavelength = h/p = h/(mv) Photoelectric effect equation (not 100% sure) The Attempt at a Solution i need to solve for v in de Broglie's equation so i can find the wavelength. i know the mass of...
28. ### DeBroglie wavelength considering relativistic effects

"Electrons are accelerated by a potential of 350kV in an electron microscope. Calculate the de Broglie wavelength of those electrons taling relativistic effects into account" I attempted the following: W = W(kin) = 350keV now W(kin)= (1-gamma)mc^2 so, now one could solve for...
29. ### Debroglie wavelength of a baseball

ok can someone please explain to me why this is wrong? debroglie of a baseball weighing 1kg is h/(1kg * v). You through this at a double slit at 10^-34 m/s which makes the wavelength equal to 6.63 meters. for a double slit its d*sin(theta) = m * (wavelength) so you get theta = sin^-1(6.63/d)...
30. ### Debroglie Wavelength: Trapped Particle's Lamda=2L/n

why is the debroglie wavelength of a trapped particle equal to lamda=2L/n?
31. ### DeBroglie wavelength its due at 12am

The deBroglie wavelength of an electron which moves with a speed of .0320 c is 7.18x10^-12 What is the fundamental minimum uncertainty in a measurement of the position of the elctron in the previous prolem if its momentum is simultaneouslymeasured to a precisioin of plus or minus one percent...