What is De broglie: Definition and 272 Discussions

Louis Victor Pierre Raymond, 7th Duc de Broglie (, also US: , French: [də bʁɔj] or [də bʁœj] (listen); 15 August 1892 – 19 March 1987) was a French physicist and aristocrat who made groundbreaking contributions to quantum theory. In his 1924 PhD thesis, he postulated the wave nature of electrons and suggested that all matter has wave properties. This concept is known as the de Broglie hypothesis, an example of wave–particle duality, and forms a central part of the theory of quantum mechanics.
De Broglie won the Nobel Prize for Physics in 1929, after the wave-like behaviour of matter was first experimentally demonstrated in 1927.
The 1925 pilot-wave model, and the wave-like behaviour of particles discovered by de Broglie was used by Erwin Schrödinger in his formulation of wave mechanics. The pilot-wave model and interpretation was then abandoned, in favor of the quantum formalism, until 1952 when it was rediscovered and enhanced by David Bohm.Louis de Broglie was the sixteenth member elected to occupy seat 1 of the Académie française in 1944, and served as Perpetual Secretary of the French Academy of Sciences. De Broglie became the first high-level scientist to call for establishment of a multi-national laboratory, a proposal that led to the establishment of the European Organization for Nuclear Research (CERN).

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  1. redtree

    Understanding De Broglie's Wave-Frequency Relationship

    The wave-frequency relationship is as follows: f = v / \lambda Therefore: v = \lambda * f The de Broglie relations are as follows: \lambda = h / p f = E / h Using some basic algebra: v = (h / p) * (E / h) v = E / p v = \gammamc^{}2 / \gammamv v = c^{}2 / v Now...
  2. R

    How does one pronounce de Broglie ?

    Well I asked three people and they all gave me three different answers... One say to pronounce it the Broglie as how you would say "broil" other one said to say Broglie as "bro-glee" last one said...Broglie as "bro-lee"
  3. B

    Exploring the Amplitude of de Broglie Waves: A Question on Mass and Velocity

    What is the amplitude of the wave produced by an object of resting mass m0 when it is going a velocity v? I haven't come across any information on the amplitude of de Broglie waves, and thus I assume that the amplitude of the wave is proportional to the Lorentz factor, m0/sqrt(1+v^2/c^2). Is...
  4. E

    Relativistic or Classical? Calculation of De Broglie Wavelength

    Relativistic or Classical?? Calculation of De Broglie Wavelength Hi there, Okay, the question is: Calculate the De Broglie Wavelength of a 10 MeV proton and a 1 MeV electron. How does one know whether to use relativistic or classical means? Relativistic => Kinetic / Rest mass >/ = 10%...
  5. A

    Calculating the Energy for Equal de Broglie Wavelengths of Photons and Electrons

    How do you calcuate at what energy do a photon and an electron have the same de broglie wavelength?
  6. E

    Speed with a de Broglie wavelength.

    1. At what speed is an electron's de Broglie wavelength: (a) 1.0 pm (b) 1.0 nm (c) 1.0 \mum (d) 1.0 mm2. \lambda = \frac{h}{mv} 3. I have solved for v, and I plugged in values, it gives me, for a = 4.54 x 10^(27) m/s, the ANSWER is: 2.77 x 10^(8) ms, it's way off, I tried converting energy into...
  7. D

    [Multiple Choice] wavelength of an object. de Broglie wavelength

    [SOLVED] [Multiple Choice] ...wavelength of an object. de Broglie wavelength 1. THE PROBLEM STATEMENT MULTIPLE CHOICE Which of the following would you expect to have the largest wavelength associated with it? (A) a quick-moving bee (B) an electron orbiting a nucleus (C) a slowly lumbering...
  8. V

    Finding KE when given de Broglie wavelength

    [SOLVED] Finding KE when given de Broglie wavelength Homework Statement What is the kinetic energy, in MeV, of a proton with a de Broglie wavelength of 10fm? 1 MeV = 10^6 eV 1 fm = 10^-15m 1 eV = 1.602 x 10^-19 J h = 6.63 x 10^-34 Js wavelength = 10 x 10^-15 m = 10^-5 nm Mass proton =...
  9. A

    De Broglie Wave Lenght And Number Of Waves K

    I could not understand very well because of the argument between me and the teacher about k space and wave length of de broglie because he said that we can not explain solid state or lattice or crystal only by suing k space or vector k not by using de broglie wave length because de broglie wave...
  10. S

    Question about Planck's constant and De Broglie

    Hello everyone, I've been studying the origins to quantum physics lately. It has been bugging me for a while that everywhere I look for information concerning the equation E=hf, does not explain where exactly the equation comes from. I know Plancks constant comes from the explanation Planck...
  11. D

    What is the relationship between energy levels and de Broglie waves?

    The Formula for computing E(n) = -(Z^2)/(n^2) * Ei is fairly straight forward. Am I right in thinking this formula refers to the energy level of the atom with Z number of protons? This formula, what it yields at least, doesn't depend on the number of electrons the atom has? Also, when...
  12. B

    De Broglie equation and black holes

    Does this apply to a black hole? What would be the consequences of it? Thanks
  13. M

    De Broglie wave length, lambda=h/mv

    for each massive body is assigned a wave length by the De Broglie formula: lambda=h/mv but, for example, a stone which has a mass of 10 kg and which is moving with a speed of 100 m/s, is assigned a wave length that goes beyond the Planck length that is the limit. how is this possible? thus...
  14. P

    For Deriving De Broglie' Wavelength

    Homework Statement The De Broglie Wavelength of any object in motion is given by \lambda=\frac{h}{P} where h is Planck's constant and P is the body's momentum. for heavy masses this wavelength is too small to be observed, nevertheless it is still there... I have seen a derivation for this...
  15. P

    Solving the De Broglie Problem: Calculating Length of a 1-D Box

    Homework Statement What is the length of a one-dimensional box in which an electron in the n=1 state has the same energy as a photon with a wavelength of 500 nm Homework Equations E=h^2/8mL^2 and E=hc/lambda making it L=sqrt( (h*lambda)/(8cm) ) The Attempt at a Solution I...
  16. P

    Question about Deriving the de Broglie Wavelength

    Something has always bothered me about the way the de Broglie relation is derived and I've never seen anyone address this, so I'm hoping someone here can. As I understand it, the derivation begins with two of Einstein's equations: E=hf, and E=pc. E=hf was experimentally obtained by Einstein...
  17. P

    The de Broglie wavelength

    The mass of an electron is 9.11*10^-31 kg. If the de Broglie wavelength for an electron in an hydrogen atom is 3.31*10^-10 m, how fast is the electron moving relative to the speed of light? The speed of light is 3.00*10^8 m/s. here's what I did: i solved for...
  18. M

    De Broglie Wavelengths: Need clarification for questions.

    Thanks for any help you can give. I just started modern physics and my teacher has a tendency to give questions that were based on things not mentioned in the book and only briefly mentioned in the lectures, so I'm a bit confused. Homework Statement 1) Calculate the distribution function of...
  19. L

    De Broglie wavelength of electron

    Homework Statement Show that the de Broglie wavelength of an electron of kinetic energy E (eV) is \lambda = \frac{12.3*10^{-8}}{E^{1/2}} Homework Equations \lambda = \frac{h}{p} E = \frac{p^2}{2m} The Attempt at a Solution I've played around with substituting and things like that, but I...
  20. S

    What Happens to My Wave-Like Nature When Driving at Half the Speed of Light?

    Say I was to somehow get in a car and drive at half the speed of light or so... my wave-like nature would show up right? What do you think this would look like from my perspective? from an observers perspective? What does it even mean to acquire a wavelength. What kind of wave do I become...
  21. X

    De Broglie Waves and Complex Numbers

    We used complex variables to describe the wave function. People do that in acoustics and optics too, strictly for convenience, because the real and imaginary parts are rudundant. The wave function of quantum mechanics is "necessarily" complex, it's not just for convenience that we use complex...
  22. H

    De Broglie wavelength of a particle

    The meaning of the De Broglie wavelength of a particle is entirely unclear to me. 1. To which kind of wave does the wavelength belong? To the wave that determines how likely the free particle is to show up in certain places (probabilities as squared amplitudes)? If yes: 2. Why is the...
  23. N

    Comparing de Broglie Wavelength to Particle Size

    Homework Statement It is an MCQ problem: How does the de Broglie wavelength λ associated with a particle compare to the size of the particle? (A) λ must be greater than the particle (B) λ must be less than he particle (C) λ could be larger and smaller than the particle Homework...
  24. A

    De Broglie & Light: My Doubt - Einstein's Calc

    i have a doubt... can someone please tell me where i am going wrong? by Einsteins calculations, rest mass of photon or something moving with v=c has zero rest mass, else its mass at motion tends to infinity, which is not possible. NOW substituting this in de broglies wavelenght eqn...
  25. C

    Relativistic De Broglie Relation

    so I'm trying to derive the De Broglie relation: \lambda = \frac{h}{p} for a relativistic particle.. I know that it can be simply written in terms of the relativistic momentum, but to complicate matters, I'm asked to write it in terms of the Kinetic energy.. the expression I'm looking for...
  26. D

    De Broglie Wavelenght of a 5.5Mev

    Calculate the de Broglie wavelenght of a 5.5 Mev alpha particle emitted from Am (241) nucleus, could this particle exist with inside the Am (241) nucleus (diameter = 1.6x10^-14m)? the wavelenght: Lambda=h/p = (hc) / (sqrt[2mc^2)xeV) = 1240 / sqrt(2x3727.38x10^6x5.5x20^6) ?
  27. P

    De Broglie wavelength of a particle

    The problems is: A particle has a de Broglie wavelength of 0.00 m. Then its kinetic energy triples. What is the particle's new de Broglie wavelength, assuming that relativistic effects can be ignored? I have no idea where to begin. Please help me:bugeye:!
  28. S

    Find the De Broglie wavelength

    Homework Statement Johnny Jumper's favorite trick is to step out of his high-rise window and fall 56.0 m into a pool. A news reporter takes a picture of 70.0 kg Johnny just before he makes a splash, using an exposure time of 7.00 ms. Find the following. (a) Johnny's de Broglie wavelength...
  29. A

    De Broglie Wavelength of Electron

    Homework Statement Ok, question is: " Calculate the de Broglie wavelength for an electron that has kinetic energy a)50.0 eV b) 50.0 keV and c) 3.00 eV d) What If? A photon has energy 3.00 eV. Find its wavelength. Homework Equations E=hf 1/2 m(v^2) *lambda* = Planck's constant /...
  30. S

    Can a stationary, massive particle have a de Broglie wavelength?

    Quick question Can a stationary, massive particle have a de Broglie wavelength? I thougt not but there is a question that doesn't state a speed. I think it might be incorrect. Cheers
  31. X

    De broglie vs classical wavelength

    since it is defined (from what i can tell) as h/p, is it interchangeable with the classical wavelength in equations involving waves in general? or is it a special separate case for matter? that is, for photons we have the following equation: E = hf E = hc/λ can the same equation be...
  32. M

    What are the equations and solutions for the De Broglie Wavelength Problem?

    Homework Statement What is each of the following? (a) the wavelength of a 6.0 eV photon m (b) the de Broglie wavelength of a 6.0 eV electron m Homework Equations ? The Attempt at a Solution None so far
  33. S

    De Broglie wavelength of a photon

    1. What is the wavelength of a 5.0 eV photon? What is the de Broglie wavelength of a 5.0 eV electron? 2.E = hc/lambda lambda = h/momentum 3. I know the first one simply 248 nm for the wavelngth. I don't know how to find the de Broglie though since I don't know what the...
  34. B

    Potentials and de Broglie wavelength

    Homework Statement Homework Equations E=hc/λ? and the Time Independent Schrodinger Equation. The Attempt at a Solution Now, would I be right in thinking for the first section that the energy for the E=hc/λ bit is just the energy of the particle given in the question (10eV)...
  35. H

    De Broglie Wavelength: Velocity & Stationary Matter

    1. Since velocity is relative to the reference frame, would the de Broglie Wavelength varies from one observer to another? 2. What will happen if the matter is stationary?
  36. W

    De Broglie wavelength for (near) stationary objects.

    Homework Statement I must be missing out on some fundamental part of quantum mechanics, since I'm unable to quite grasp the following thought experiment. A 1kg ball is confined in a onedimensional box with a length of 1m. What is it's maximal De Broglie wavelength? Homework Equations...
  37. D

    What is the predicted de Broglie wavelength of a bullet traveling at 1060 m/s?

    Homework Statement A bullet of mass 39 g travels at 1060 m/s. Although the bullet is clearly too large to be treated as a matter wave, determine what Eq. 38-13 predicts for the de Broglie wavelength of the bullet at that speed? Homework Equations de Broglie equation: wavelength = h / p...
  38. L

    Who Was the First to Use Wave Mechanics to Study Electrons in the Hydrogen Atom?

    Here is an objective question: The first full presentation of the behavior of electron in hydrogen atom by using wave mechanics is by: Louis de Broglie or Schrodinger? As far as I know, Schrodinger is famous for his wave equation. Meanwhile, de Broglie is known for the equation lambda= h/mv.
  39. Reshma

    Find the de Broglie wavelength of an electron

    Find the de Broglie wavelength of an electron with KE: a]10eV b]1KeV c]1MeV d]100MeV Formulae: Relativistic \lambda = \frac{h}{\sqrt{{(E/c)}^2 - m_0^2c^4}} Non-relativistic \lambda = \frac{h}{\sqrt{2mE}} I am wondering for which case(s) should I apply the relativistic or the non-relativistic...
  40. C

    Localization vs De Broglie wavelenght

    Localization vs De Broglie wavelength First of all, I would like to say hello to everybody since this is my first post, even if it's been some time since I read Physics Forums. Second, sorry for my bad English, I'm Italian :) Third, the issue: I read from my teacher's notes, that a...
  41. J

    De Broglie wavelength question

    I have been instructed to calculate the de Broglie wavelength of a proton moving at 1) 2 x 10^4 m/s and 2) 2 x 10^7 m/s For the first velocity, the particle is not relativistic, but for the second velocity the particle is. can someone explain to me what makes velocity 2 relativistic? thanks.
  42. Robert100

    Do all objects really have a de Broglie wavelength?

    When I was learning about gravity, I was taught that F = [G(m1)(m2)]/r^2, and that this equation was valid for r (the distance between mass 1 and mass 2) at all distance scales. However I now know better: Physicists today admit that we do not know that this relationship is true at all scales...
  43. U

    Verifying Solutions of de Broglie Form of Schr. Eqn

    I am to show that neither of the two wave functions \psi_1 (x,t) = M_1 e^{kx-\omega t} and \psi_2 (x,t) = M_2 e^{i(kx-\omega t)} solve the de Broglie form of Schr. Eqn: -\frac{\hbar ^2}{2m} \frac{\partial ^2 \psi}{\partial x^2}=i \hbar \frac{\partial \psi}{\partial t} for the first wave, i...
  44. U

    Solving De Broglie Wave: Direction & F/G

    the de Broglie wave has the form: /psi = e^{i(px-Et)/ \hbar} 1. I am asked the direction of this wave. To me, as t increases, the x has to increase as well to keep a constant function on the left hand side so I believe that the direction of this wavelangth is heading towards the positive end...
  45. Q

    How Does the De Broglie Wavelength Relate to Scattering Angles?

    we were having a discussion about this in physics and my teacher mentioned a relationship between the formula and some angle (don't know which!) but it's not on the syllabus any more, i was wondering does anyone know anything about this? cheers for the help
  46. A

    Estimate Min. Electron Energy in Hydrogen Atom w/ Uncertainty Principle

    for the following question: a hydorgen atom is 5.3*10^(-11) m in radius. use the uncertainty principle to estimate the minimum energy an electron acan have in this atom. my problem: to calculate the kinetic energy, do you use Ek=(p^2)/2m or Ek=pc?
  47. P

    Derivation of De Broglie wavelength

    The De Broglie wavelength was derived like this by our physics teacher. E=hf v=fλ E=mc^2 so hf=mc^2 hv=λmc^2 Then the WRONG BIT h=λmv h=λρ λ=h/ρ But that only works for light (when c=v). There must be a correct way of deriving it for electrons etc. We are...
  48. A

    Electric fields and de broglie wavelength

    I'm confused as to how the concept that 'things' have a wavelength applies to an electromagnetic field, which has momentum, but not mass: what 'things' have wavelengths? Are there other criteria, other than whether something has mass or momentum, that must be fufilled before talking about...
  49. D

    De Broglie Waves: How Did He Come Up With It?

    How did De Brogie come up with the idea that matter are waves.
  50. S

    De Broglie Wavelengths & Electron Orbitals

    Hi everyone, I read that: The electron (according to de broglie) can be described by a summation of many different waves according to PSI(X,t)= integration (A e^i(kx-wt)) Does each wave correspond to a certain orbital? and if each of them is for an...
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