De broglie wavelength Definition and 150 Threads

Homework Statement What is the de Broglie wavelength of this electron? Given is 500 eV Homework Equations KE= 1/2 mv^2 1 eV=1.602x19^-19 J The Attempt at a Solution I converted the 500 eV to 8.01x10^-17 via the given conversion. Now I'm stuck.

In Classical Mechanics the derivative of Kinetic energy with respect to velocity is momentum, so I was wondering if this is valid: In this L is lambda or wavelength and h is Planck's Constant. E=hf, therefore E=h(v/L) This means that dE/dv=h/L.(h and L are constants and the derivative of...

Homework Statement De Broglie wavelength What is the De Broglie wavelength of the 1.0-TeV (1TeV=1012eV) protons (mpc2=938.3MeV) accelerated at the Fermilab Tevatron accelerator? These high-energy protons are needed to probe elementary particles [Hint: You need to use relativistic formula, but...

If, in the expression for the de Broglie wavelength, we let m -> infinity, do we get the classical result for matter? de Broglie wavelength = h/mv so as m goes to infinity the de Broglie wavelength goes to 0. So does this mean that particles with larger mass don't display wavelike...

Homework Statement If the be Broglie wavelength associated to the first orbit of the electron inside the atom of hydrogen is 62.4 nm, what is the wavelength associated to the fourth orbit? 1. 62.4 nm 2. 124.8 nm 3. 312 nm 4. 249.6 nm Homework Equations # of...

Homework Statement I am trying to describe the limit for the minimum radius of a star to first year university level students in order to describe the reason for the size of the Sun. I'm a bit confused by the critical density of the material in the star's core and how we know that the main...

Homework Statement The question is from Advanced Physics by Adams and Allday, section 8 Practice Exam Questions, question 30. Estimate the de Broglie wavelength of an electron that has been emitted thermionically in a vacuum from a filament and then accelerated through a p.d. of 30.0 kV...

Homework Statement Question 1) Calculate the de Broglie wavelength of a neutron (mn = 1.67493×10-27 kg) moving at one fiftieth of the speed of light (c/50). Question 2) Calculate the velocity of an electron (me = 9.10939×10-31 kg) having a de Broglie wavelength of 225.7 pm...

what does the momentum in de broglie wavelength signify? i mean how do u defien it...we can define the expectation in momentum but how do we define momentum for "quantum mechanincal" particles

The de broglie wavelength is h/p, where p is momentum, and hence mv, so wavelenght = h/ (mv). The mass is on the denominator, so a massive object, like a baseball, will have a small wavelength, beyond detection and we can ignore it. OK, so does the mass have to be moving to have a de broglie...

Homework Statement A 220lb fullback runs the 40-yd dash at a speed of 19.6 ± 0.1 mi/h. What is he de Broglie wavelength (in meters)? Homework Equations de Broglie Wavelength: λ=h/(mu), where λ=wavelenght, h=6.626 x 10^(-34) kgm^2)/s, m=mass (kg), and u= speed The Attempt at a...

Homework Statement Calculate the de broglie wavelength (DBW) of an electron with kinetic energy 60 GeV. What percentage of an atom's diameter can it penetrate? Homework Equations DBW = h/p p=mv The Attempt at a Solution Basically I have an electron traveling at the...

I had a go at 2 Q's and wanted to make sure I'm doing this right. so here's the first one, and maybe if i went wrong with it I was going to redo the 2nd Q on my own. \lambda = h/p = h/mv (\sqrt{1-((v^2)/(c^2))}) so, an Alpha Particle traveling @ 2x106m/s (mass = 6.645x10-27 kg)...

Homework Statement An electron has a de Broglie wavelength of λ = 6.4e-10m. What is its speed? What voltage was needed to accelerate to this speed? Homework Equations v=h/mλ KE = 1/2mv^2 The Attempt at a Solution I already determined that the speed is 1.136e6 m/s. Finding the...

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%...

How do you calcuate at what energy do a photon and an electron have the same 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...

[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...

[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 =...

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...

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...

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...

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...

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...

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:!

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...

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 /...

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

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

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...

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)...

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?

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...

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...

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.

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...

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

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...

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...

I had a physics exam today in which we were presented with a model of a hydrogen atom with a single electron orbiting a single proton. We were told the radius of the "orbit" of the electron, and subsequently had to calculate the electrostatic force between the proton and the electron and the...

Due to time constraints in AP physics we had to skip the chapter on realitivity and now we have problems in the next chapter that request us to use relativity: At what energy will the nonrelativistic calculation of the de Broglie wavelength of an electron be in error by 5%? Any help on...

Is there a relativistic formulation of the de Broglie wave length equation?

I have the formula for the de Broglie wavelength but for some reason I'm not using it properly. Here's the question: What is the De Broglie wavelength (in nm) of a proton with a kinetic energy of 10 eV? (Take the mass of a proton to be 938 MeV/c2.) \lambda = \frac{hc}{pc} hc = 1239.8...

Hi ppl I have a short question concerning the de Broglie hypothesis. I worked out the de Broglie wavelength of an electron in a TV picture tube accelerated by 20,000 V, using the fact that mv^2/2 = QV and then that lambda=h/mv. Now I need to answer whether this is relativistic or not, how do I...

Louis de Broglie hypothesized every particle moving with momentum p has a wavelength of \lambda=\frac{h}{p} If I understand it correctly, is the de Broglie wavelength directly related to the wavelength of \psi(x)? But because according to quantum physics, the particle coexists with the...

The initial kinetic energy of a free particle is E and has wavelength \lambda. What is the de Broglie wavelength of a particle in a potential V? This is what I have so far: Since k=\frac{\sqrt{2mE}}{\hbar}, the original de Broglie wavelength of the a free particle is: \lambda =...

Ok so my homework question says find the de broglie wavelength of a 100 gram ball traveling at 100 miles per hour. So do a little dimensional analysis and 100 mph is 44.704 m/s and since the de broglie wavelength is found with lamda=h/p and p=mv then I am good to go, I get 1.48 x 10^(-24)...

When textbooks introduce the de Broglie wavelength of a particle they always ask you to calculate the wavelength of a macroscopic object like a football or something. Then they conclude: "Since the wavelength of ordinary objects like footballs are only 0.00001 nm (or whatever) quantum mechanics...

we have seen that for massless (rest) patricle.we can relate the particle nature with the wave nature by einstein's relation. what about the matter waves? we cann't use the same relativistic equation for the momentum energy relation to generalise that to matter waves too,because rest mass is...

Given: in region 1, x < 0, U = u0 > 0 in region 2, 0≤x≤L, U = 0 in region 3, L < x, U = u0 (same as in region 1) total energy E constant everyplace, E > u0, and a particle is moving towards the right beginning at some x<0. So, in region 1: \frac{d^2\psi_1}{dx^2} =...