Barrier Definition and 241 Threads

Homework Statement There isn't an exact problem I'm struggling with, it's one small part of a larger problem, which involves finding the probability protons will penetrate the Coulomb barrier. I'm trying to understand an example in my notes, and the bit that confuses me is attached as an...

Schottky barrier ! ? hi all something i can't understand in the schottky barrier diode i know that when electrons move from semiconductor(n type) to metal a depletion region appears in the n side so potentail difference is created so for electrons to move from S.c to metal they need to...

There is the atmosphere that is composed of 4 parts: the troposphere, the stratosphere, the mesosphere, and the thermosphere. I know that air is a gas made up of molecules. And a gas fills up the container it is contained in, which is the atmosphere. 1Most of the mass of molecules are in the...

Homework Statement Two different ideal gases are separated by a sliding barrier that can move vertically. The gas in the upper chamber 1 has n moles of material, whilst the gas in the lower chamber 2 has 3n moles of material. At T0 the weight of the barrier is such that the volumes of the two...

In QM textbook, there is the solution of shroedinger Eq. on the rectangular potential barrier. The reflection rate can be caculated in each case, E>V0, E=V0 and E<V0. But, I can't find the experiment on the rectangular potential barrier anywhere. Is there anybody who does or sees such an...

Homework Statement I need help with part (iii) and (ii) of the follwoing problem: http://img228.imageshack.us/img228/516/79620850.jpg Homework Equations From my notes transmission coefficient for E<U is: T(E)= \left[ 1+\frac{1}{4} \left( \frac{U^2}{E(U-E)} \right) sinh^2 (\alpha L)...

Hello people, I'm trying to plot probability distributions from the given potential numerically. These are the results (particle coming from the right) https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/s720x720/546478_516459578368236_1799346634_n.jpg What I want to know is why does...

Homework Statement A proton's energy is 1.30 MeV below the top of a 14.0 fm-wide energy barrier, What is the probability that the proton will tunnel through the barrier? Homework Equations η=\frac{\hbar}{\sqrt{2m(U_{0}-E)}} P_{tunneling}=e^{\frac{-2w}{η}}The Attempt at a Solution I have...

I could use a basic explanation of how half-lives are associated with the fission barrier. Are half-lives still present in induced fission and not just spontaneous fission? Thanks

Interesting. According to the following link: http://www.sciencedaily.com/releases/2012/04/120423143128.htm What do you all make of this?

To anyone that can help me, Hello everyone. I am student from Mechanical Engineering and I am very new to electronic field. I currently doing my final year project which is developing the high voltage discharge circuit for the DBD plasma. The middle electronic elements is the representative...

A wave packet of mean energy E0 is incident on a potential square barrier. The figure below shows stills from a film showing 9 successive stages in interaction. a) True or false? The incident packet at time t = 0 describes many particles, each in a different momentum state. If false, tell...

I am not an expert on Physics and have for the past year been engulfed in work, so I am very rusty. I read a comment online recently that essentially said the laws of physics simply prevent any object from accelerating to the speed of light (infinite energy required?), but do not say that an...

Homework Statement There is a step barrier at x=0, V_0 > E I am given: ψi = e^i(kx−ωt) ---> ψr = R e^i(−kx−ωt) <--- ψt = T e^(−αx−iωt) ---> Part of question I am confused about: State the two boundary conditions satisfied by the wave function at x = 0 and hence find...

if ψ=C*e^(kx) + D*e^(-kx) show that the probability current density is Jx=(i*k*hbar/m)[c*conj(D) - conj(C)*D] since Jx= (i*hbar/2m)*[ψ * derivative of conj(ψ) - conj(ψ)*derivative of ψ] ψ=C*e^(kx) + D*e^(-kx) conj(ψ)= conj(C)*e^(-kx) + conj(D)*e^(kx) ψ ' = C*k*e^(kx) - D*K*e^(-kx)...

Hello, A Schottky barrier is said to have rectifying characteristics, which from what I can understand is bad ...but would the rectifying characteristics mean that current passing through the junction would be flat ...level is probably a better way to describe it rather than flat. I only...

I am looking for a book that explains how a Schottky barrier is formed at a semiconductor metal interface. I have found the attached diagram in a source that i cannot see the references for. Does anyone know of a book containing such a diagram and an explanation of the formation of a Schottky...

Homework Statement 224Ra --> 220Rn + \alpha 224Ra --> 212Pb + 12C 224Ra --> 210Pb + 14C Calculate the Q-Values (in MeV) for these decays given their atomic mass excesses (in MeV) are 88225Ra = 18.818 86220Rn = 10.604 82212Pb = -7.557 \alpha = 2.425 82210Pb = -14.743...

Hello. I was womdering does anyone know any good resources of information on Fermi level de-pinning & Schottky barriers? I have been hunting around online, with not much luck. I thought someone here might be able to suggest some things. Thanks. Seán

Homework Statement I'll try to recreate from my memory the problem we've been assigned on a test more than one month ago. They gave the solution but I either misunderstood or miscopied it. An electron with kinetic energy 5 eV goes from a region with potential V_0=6 eV (let's call this region...

Homework Statement A particle of mass m goes toward the unidimensional barrier potential of the form V(x)=0 for x\leq 0 and a\leq x and V(x)=V_0 for 0<x<a. 1)Write the corresponding Schrödinger's equation. 2)Calculate the transmission coefficient for the cases 0<E<V_0 and E>V_0. Hint: Check...

Homework Statement Force exerted on a car by a crash barrier as the barrier crushes is F=-(4.5+140s) kN where s is the distance in metres from the initial contact. If a car of mass 2000 kg is traveling at 100 km/h when it hits the barrier the barrier deformation required to bring the car to...

How much energy particles must have in order to overcome the Coulomb Barrier? Or the correct way to ask this is how much temperature is required for this?

Homework Statement A particle is in the ground state of a half harmonic oscillator (V=m/2 w^2 x^2 x>0, and infinity x<0). At t=0, the barrier at x=0 is suddenly removed. Find the possible energy measurements as a function of time and the wavefunction for all times. Homework Equations <H>...

Homework Statement What temperature would be required for two protons to collide if quantum mechanical tunneling is neglected? Assume that nuclei having velocities ten times the root mean square (rms) value for the Maxwell-Boltzmann distribution can overcome the Coulomb barrier (which you can...

Homework Statement V(x) = 0 for x < 0; V0 for 0 < x < a; 0 for x > a Particle of mass m E=V0 Asks for general solution and transmission coefficient. Homework Equations Time-Independent Schrodinger Equation The Attempt at a Solution I've found region I (the left region where x <0) to be...

This is something that has always bugged me about relativity... I must be missing something... Lets say you have a space station sitting stationary out in space... a spaceship approaches it from one side at .75c...another ship approaches the station from the other side, also at .75c, still no...

The wavefunction associated with a free particle must be continuous at the barrier and will show an exponential decay inside the barrier. Why it shows an exponential decay inside the barrier? After coming out of the barrier, there is reduced probability for the particle. When there is no loss of...

Suppose that one electron from the end of the universe is emitted to the quantum rectangular barrier potential whose size amouts to galaxy size. This belongs to step potential problem or rectangular barrier potential problem? The textbook on Quantum mechanics doesn't deal with the case...

Homework Statement A 1.1 eV electron has a 10-4 probability of tunneling through a 2.4 eV potential barrier. What is the probability of a 1.1 eV proton tunneling through the same barrier Homework Equations eq 1) T= [1 + V02 sinh2(kL)/4E(V0-E)]-1 or if (kL)>>1 we use eq 2) T=...

Homework Statement An electron with kinetic energy 5 eV (8.01E-19 J) passes through a 3 eV (4.806E-19 J) potential barrier. There are certain widths for this potential barrier in which the transmission probability will equal one hundred percent and the reflection probability will equal zero...

Please explain to me what I'm missing: You can't go faster than the speed of light, because of time dilation. The faster you go, the slower time moves for you as compared to objects at rest, and time would stop for you if you ever went the speed of light. That's what makes C the universal...

Dear All I am having problems with how to draw band diagrams with band bending for Schottky Barriers and PN junctions. My issue is that I don't know how you determine which Fermi level remains fixed at its equilibrium level and which Fermi level moves to align with it when the two materials...

As we know the potential barrier of silicon diode is 0.7V at "Normal Temperature" But if the Temperature is 120 degree Centigrade then what will happen? 1) the Potential Barrier will increase 2) Decrease 3) Remain Same Please Explain also!

Homework Statement I'm asked to calculate the reflection and transmission coefficients for scattering from a potential energy barrier. The potential energy barrier is, V(x)=\frac{\hbar^2}{2m} \frac{\lambda}{b} \delta(x) where \delta (x) is the Dirac delta function. Homework Equations See...

An electron having total energy E=4.46 eV approaches a rectangular energy barrier with U=5.02 eV and L=949 pm. Calculate this probability, which is the transmission coefficient. I thought this would be an easy one, given that T=e-2GL and G=\sqrt{\frac{2m(U-E)}{H}} where H is the...

Hi! I'm struggeling with a quantum mechanical problem. Homework Statement An alpha-particle is "trapped" inside a uraniumcore, and the potential is simplified to 0 for R2 < r V0 for R1<= r <= R2 0 for 0<= r < R1 I have calculated the transmission coefficient T =...

After hours searching the web I was not able to find the unidimensional case "a finite barrier inside a finite well". I would appreciate if someone could give me a reference about it.

Homework Statement Two copper conducting wires are separated by an insulating oxide layer. This layer acts as a square barrier of height 10 eV. Estimate the transmission coefficient for penetration by 7 eV electrons (a) if the layer thickness if 5 nm and (b) if the layer thickness is 1 nm...

Red-capillary Purple- Basement membrane Blue-podocyte Hello everyone, Now my question is after something if filtered from the capillary how does it go to the podocyte. The basement membrane looks too thick with no pores to me, it seems to be blocking the passage of molecules. Thanks :smile:

Homework Statement We have a potential structure as follows: from z=negative infinity to z=-b, the potential is 0. At z=-b, the potential jumps up to some V_0. Then, at z=0, there is a potential barrier of infinite height. I need to solve for the magnitude of the reflected wave (i.e. the wave...

I know it may not even be mechanically possible to reach the speed of sound underwater (1,484 m/s); but this is just a theory. After discussing with several people, what would happen if a submarine was to break the sound barrier underwater, a couple of interesting theories arose. Going...

I'm currently studying Freidberg's plasma physics and fusion energy book, I've heard that Fusion between Deutrium and tritium is most suitable for a fusion reactor and how columb barrier plays its role....my question is what happens when two neutrons fuse together? do they face columb collision?

How fast must a human throw a baseball in order to break the sound barrier? I know a jet breaks the sound barrier at approximately 750 mph but would it be the same for a human?

I am trying to find out what is the correct way to write the mathematical demarkation for the Coulomb Barrier. You know, if I wanted to write the symbol for the radius of the coulomb barrier. If anyone could show me it in the correct font that would be great. NO, this isn't for...

b]1. Homework Statement [/b] Consider a particle of mass m incident on a rectangular barrier with a potential V(x) = V0 for 0 \leq x < w V(x) = 0 otherwise, where V0 is a positive constant. The particle has an energy E > V0. Find expressions in...

Homework Statement a particle of kinetic energy E is incident from left on a potential barrier,height U, situated at the origin.the barrier is infinitely wide and E>U obtain an expression for the reflection coefficient R of the particle as a fuction ratio e=E/U Homework Equations...

Hi, I'm trying to understand the quantum mechanical solution to this potential: V(x) = \left\{\begin{array}{cc}\infty & \mbox{ for } x < 0,\\-\lambda\delta(x-d) & \mbox { for } x > 0\end{array}\right. A particle of mass m is constrained to move on the half straight line \{x \in \mathbb{R}: x...

Will installing perforated radiant barrier insulation in the attic reduce the power bill significantly.

Having trouble drawing the wave representations for this diagram. [PLAIN]http://img156.imageshack.us/img156/94/diag.png I'm not sure what the incident and reflected waves should look like. The question is asking to draw the waves in each region. I understand how to calculate the waves just...