Barrier Definition and 241 Threads

Hope this is the right place for this question, but it is very inetresting to me so I wanted to ask some experts. Can a propeller driven aircraft break the sound barrier? My answer, no. Any opinions will help Thanks

Let's have a kind of step potential, V=infinity, where x\leq0, V=constant, where 0\leqx\leqa, V=zero , where x\geqa. Then, my question is that when the energy of the particle is lesser than zero, which means that the particle is in the bound state, is there a probability of getting...

Homework Statement The well is set up exactly like this https://www.physicsforums.com/showthread.php?t=397977&highlight=potential+barrier+inside+an+infinite+square+well. It is basically a infinite potential well with a barrier in the center. Basically I've got solutions for regions 1, 2...

Homework Statement In delta potential barrier problem Schrodinger equation we get \psi(x)=Ae^{kx}, x<0 \psi(x)=Ae^{-kx}, x>0 We must get solution of lim_{\epsilon \rightarrow 0} \int^{\epsilon}_{-\epsilon}\frac{d^2\psi}{dx^2}dx Homework Equations The Attempt at a Solution lim_{\epsilon...

Homework Statement A beam of particles, each of mass m and kinetic energy E, is incident on a potential barrier V(x) = V_0 \; \; for \; \; 0 \leq x \leq a \; \; \; \; \; \; \; \; \; = 0 \; \; for \; \; x < 0 \; \; and \; \; x > a E = V_0 \; \mbox{is the special case} The part...

Electron beam with kinetic energy E_{k} = 10 eV strikes a positive potential barrier V_{0} and the kinetic energy after the beam has passed through the barrier is E_{k} = (10 eV -V_{0}). How big potential V_{0} is needed so that 40% of the electron beam is going to be reflected? What...

im generating potentials, however the coulomb is proving tricky. stumbling block is finding a way to write A coth(2x) + B cosech(2x)= (A+B)/2 tanh(x)+(A_B)/2 coth(x) i am at the RHS and need to get the tanh to come out which I am told can be done. the a's and b's might not be quite right...

Homework Statement In a particular atom, an alpha particle makes N collisions with a potential barrier in each second. The transmission coefficient at the barrier is 1.0e-15. In one second, 2.0e18 alpha particles are emitted from a group of 3.0e23 radioactive atoms. Find N. Homework...

Homework Statement Consider particles incident on a potential energy step with E<U. (That is, a particle with total energy E travels along one dimension where U=0, then crosses, at point x=0 into a region where U>E.) (The particle is incident on the potential energy step from the negative x...

Barrier potential, E> V0 V(X) = 0 ( x < 0 ) = V0 ( 0 < x < a ) = 0 ( x> a ) Psi(x)1 = Aexp[ik1x] + B exp[-ik1x] Psi(x)2 = Cexp[ik2x] + D exp[-ik2x] Psi(x)3 = Fexp[ik1x] + G exp[-ik1x] ( K3= K1 so I put k1 ) and G = 0 because there is no reflection, I used B.C...

If you have a rectangular square potential barrier of some height, say \lambda/L, and thickness L, what is the transmission coefficient and what is its value in the limit that L goes to 0? Thus you have the height of the barrier going to infinity, while the width goes to zero... Assuming...

Hey everyone, For my a research project on quantum tunneling I have to tie in math somehow, so I was wondering if anyone could help me learn to calculate the probability of a wave (preferably like an electron or electrical voltage) of some sort passing through a rectangular barrier, which is...

Hello to all, I am looking at a scattering example in my book. A particle is incident from the left with energy E > Vo. The barrier is of width L, and located between x = 0 and x = L. The solutions to the time-independent Schrodinger equation in eacch of the regions comprising the left...

Homework Statement To calculate the height of the potential barrier for a head on collision between two deuterons given that each deuteron is a sphere of radius R Homework Equations Potential of the first deuteron at a distance of 2R from it =V = ke/2R where k = 9 * 10^9 , e= 1.6 *...

Homework Statement A projectile is thrown from the horizontal ground with a speed of 40 m/sec at an angle with the horizontal of 30 degrees. At what height will the projectile strike a high barrier located at a distance of 85m from the firing point? Homework Equations ok so: point A is...

Homework Statement I am trying to find the coefficients in a Schrodinger equation approaching a finite potential. https://www.physicsforums.com/showthread.php?t=203385 It is a problem similar to this, except a little easier. In my case, though, there is no V1 as shown in the picture at the...

Hi. Firstly, can a particle every be found within the potential barrier? I've used the search function to look for an answer for this question, but I didn't really get anything conclusive. However, from what I gather, since there is a probability associated with it being 'found'(meaning it...

Question: Determine the transmission coefficient for a rectangular barrier. Treat separately the three cases E<0, E=Vo, E>Vo (note that the wave function inside the barrier is different in the three cases. and V(x) = Vo > 0 for -a < x < a = 0 for |x| > a I...

So I know this topic of tunneling has been discussed hundreds of times on this forum, but I simply cannot find nor deduce an answer to a burning question I have about what happens exactly INSIDE the barrier and how to describe it (preferably in layman's terms.) The problem is basic: A...

HI,all This is rajasekhar , Please guide me how to solve below problem. An electron moves in a one-dimensional potential of width 8 angstroms and depth 12eV then how to found number of bound states present? Thanks&Regaurds

HI,all This is rajasekhar , Please guide me how to solve below problem. An electron moves in a one-dimensional potential of width 8 angstroms and depth 12eV then how to found number of bound states present? Thanks&Regaurds

Homework Statement A particle of energy E approaches a step barrier of height U0. What should be the ratio E/U0 so that the reflection coefficient is 0.43? Homework Equations R=(k1-k2)^2/(k1+k2)^2 <--------reflection coefficient The Attempt at a Solution I am completely stumped...

Homework Statement Find the transmission and reflection coefficients for: V(x)=\left\{\begin{matrix} V_0, & -a\leq x\leq a\\ 0, & elsewhere \end{matrix}\right. Homework Equations \frac{-\hbar^2}{2m}\frac{\partial^2 }{\partial x^2}\psi+V\psi=E\psi The Attempt at a Solution I...

Hello, I was trying to design a movie in Matlab. A Gaussian wave packet moves toward double barrier then some wave reflect and some pass out from the barrier . i design the double barrier in Matlab. but don't know how to make movie in Matlab with Gaussian wavepacket. can you help. Do u have...

Sorry for such a simple question, but what are the differences between using insulation and heat reflective material? What is the effective of using them together? In my case I want to shield flammable foam insulation from melting or catching fire from a nearby heater. Will covering the...

How can we create a potential barrier? And how does it exactly acts as barrier in electron transfer?

Has it be done? And what's the sound barrier in space and can it be broken?

http://en.wikipedia.org/wiki/10-second_barrier

I'm unsure how to approach this, as solid blocks of materials next to each other (e.g. steel and air) with no barrier inbetween as shown on http://en.wikipedia.org/wiki/Thermal_conductivity "x" would equal zero, this can't be correct. Is there another equation relating temperature difference...

Dears what is "barrier transparency" and what is "quantum tunnling" in fusion? Regards

Homework Statement A beam of electrons of KE = 100 eV is incident from the left on a barrier which is 200 eV high and 10 nm wide. If the momentum spread is sufficiently narrow, then a simple plane wave is a good approximation. Recall that the mass of an electron is mc2 = 511 keV. ....._____...

Homework Statement Determine the transmission coefficient for a rectangular barrier. Treat seperately the three cases E<Vo, E>Vo, and E=Vo.Homework Equations V(x)= +Vo if -a<xa V(x)= 0 otherwise Transmission coefficient=(amplitude of transmited wave)2/(amplitude of incoming wave)2 I am also...

Homework Statement An electron approaches a potential barrier 10 eV high and 0.5 nm wide. If the electron has a 1% chance of tunnelling through, what must be its energy? Homework Equations don't know how to put equations in eg how do i get something like alpha and theta etc...

assuming that the electron has an incident energy of 8eV and that the barrier is of height Vo=13eV and width L=5x10-10m calculate the probability that the electron will be able to tunnel through the barrier.Relevant equations= k = (sqrt(2m(V-E)) /h-answer (sqrt(2x9.1x10-31(13-8)x1.6x10-19)x2pi...

Homework Statement write the solutions to the S.E in regions x<o and x between o and a C:\Users\karthik\Desktop Homework Equations I believe psi(x)= e^ikx+Re^-ikx in x<0 and psi(x)=Ae^iqx+Be^-iqx for x b/w o and a. The Attempt at a Solution My question is, since there is...

Just a quick question. Solving the Schrodinger equation (time-independent) for an infinite potential barrier, I end up with two wavefunctions. In region I, V(x)=0 \Rightarrow\psi(x)=Acos(\frac{\sqrt{2mE}}{\hbar}x)+Bsin(\frac{\sqrt{2mE}}{\hbar}x) In region II, V(x)=\infty...

I don't want to double post, so I'll just post the link to my original physicsforums.com post since my question is probably more of a physics than engineer question --> https://www.physicsforums.com/showthread.php?t=274887" Thanks for any help, Paul

Hi, Is this the correct place to post this? Perhaps it's more of a physics question. I'm trying to write a small program to design basic Schottky diodes. I'm using the following equation to calculate the current produced by a small applied voltage, far below Vt --> I = A * Aast * T^2 *...

http://www.sciencedaily.com/releases/2008/11/081114081213.htm Up to now, industrially-deployed motors have normally reached 250,000 revolutions per minute. Now, however, researchers from ETH Zurich’s Department of Power Electronics have developed a drive system in cooperation with its...

What's an energy barrir to rotation? I have data on the enrgy at anti and gauche conformations of 1-iodopropane. I have also graphed the data (steric energy vs dihedral angle) from the graph, do I just subtract the trough at anti from the trough at gauche? so from anti to gauche, it'd be...

Homework Statement A 10-eV electron is incident on a potential barrier of height 25eV and width 1 nm. Use equation 6-76 to calculate the order of magnitude of the probablity that the electron will tunnel through the barriers. Repeat with width .1nm Homework EquationsEquation 6-76 is: E =...

Solved... i think. It's just Psi(x) = B sin kx Homework Statement Consider a free particle psi(x) = A*e^(ikx) approaching an infinite barrier from the left: V = 0, x < 0 and V = oo, x >= 0. For this problem use only the time-independent Schrodinger Equation. a. Find the probability of being...

I have a question about protein folding. I have heard that there is a free energy barrier to overcome in going from the unfolded (ensemble) to folded states, and that this barrier is largely entropic -- i.e., as the (idealized, general) protein starts to fold, it loses more in entropy than it...

I'm still in Intro Physics, and I'm a little perplexed by the concept of tunneling. An alpha particle escapes the nucleus by overcoming a potential energy barrier created by Coulombic repulsion with the protons of the nucleus, but this is a spontaneous process and does not require E input...

Homework Statement hey all! i have a relli urgent question that needs to be answered in as much detail as possible...hope someone can help... Q: How is a particle, with energy of lower value than the potential barrier, able to penetrate through the barrier? (ans cannot have reasons like...

hi,... i unfortunately couldn't find a solution to this problem although it seems like a classical textbook problem... how can i solve the (time independent) schroedingerequation for the following potential V(x) = \infty for x<=-1 V(x) = a\delta(x) for -1<x<1 V(x) = \infty for x>=1 so at x=0...

Hi everyone, just wanting to know if anyone could help me out about particles tunnelling through square barriers with inital energy E<Vo. Does the energy of the particle change as it tunnels through the square barrier?

analyzing the simple-step scattering problem for E<V, we find that the solution to the schroedinger equation is: PHI(left) = Aexp(ikx)+Bexp(-ikx) PHI(right) = Cexp(-qx) Continuity of the function and it's derivative at x=0 gives the relations between the parameters A, B and C. Solving the...

1. Homework Statement b). Find the kinetic energy K (sub t), the proton will have on the other side of the barrier if it tunnels through the barrier. c) Find the kinetic energy K (sub r), it will have if it reflects from the barrier. Variables: Transmission Coefficient (T) T= e^-2bL T...

1. Homework Statement b). Find the kinetic energy K (sub t), the proton will have on the other side of the barrier if it tunnels through the barrier. c) Find the kinetic energy K (sub r), it will have if it reflects from the barrier. Variables: Transmission Coefficient (T) T=...