Energies Definition and 299 Threads

hi, I'm new on this forum, and I don't know english very well (sorry). maybe you can clarify me about this doubt. an electron in a well with infinite walls has a discrete set of energies, right? but if the length of the well is infinite, what can I say about energy state density? is it uniform...

Homework Statement Homework Equations Given in the question The Attempt at a Solution Using the numbers and equation given in the question, I got a binding energy of Thorium of 1743.64MeV, and a binding energy of Radon (?) of 1720.88MeV I've come across a number of this style...

Given that the average kinetic energy for molecules of an ideal gas is <E>=3/2kT, how can one find the percentage of molecules of the gas that contain energy above this value?

If one reads the current version of the wikipedia entry on Photoelectric_effect we see that historically the postulate E=h f predates the relativistic theory. So it is kind of circular to argue in terms of E=h \nu to justify E=h f. The empirical process first postulated E=h f for the black...

[SOLVED] energies of spin states Homework Statement An electron is in a constant magnetic field with magnitude B_0, aligned in the -z direction. My book says without explanation: "the spin-up state has energy -\mu_B B_0" where \mu_B is the Bohr magneton I looked back in the Spin...

[SOLVED] Energies of a Hydrogen Atom 1. I have a question on the ratio of energies of an electron in a hydrogen atom. It seems quite simple, but yet seem to be struggling...can anyone help? 2. The question is: "calculate the most probable value of the electron-orbit radius, r, and the ratio of...

Hi, Let's consider a plasma of 3 distinct populations : 1 cold proton population of 0.2 density, 1 hot proton population of 0.8 density, and one electron population. I have T_i=T_e and I set the velocity of my cold population to 0. I expected that te energy of my hot proton population to...

Homework Statement A 2-kg block is dropped from a height of 0.4 m onto a spring force whose constant k is 1960 N/m. Find the maximum distance the spring will be compressed. Homework Equations U1+K1=U2+K2 The Attempt at a Solution both the initial and final kinetic energy should be...

I've looked around and not found any good sources on the gamma energies from fast neutron activation. I need to find the characteristic gamma rays for an MCNP project and currently, I'm relying on energies I get from running some simple cases I set up for the element of interest. Does anyone...

1. Jane, whose mass is 49.0 kg, needs to swing across a river filled with man-eating crocodiles in order to rescue Tarzan, whose mass is 80.0 kg. However, she must swing into a constant horizontal wind force F on a vine that is initially at an angle of with the vertical. (See Fig. P5.73.) In the...

Homework Statement Find the ratio of the energies of the K characteristic x rays of carbon to those of Magnesium. Homework Equations The Attempt at a Solution I did it using Bohr's expression of energy...Is there any other method to do it?

Homework Statement Find the kinetic energy of an electron in the lowest allowed energy state of a hydrogen atom. Homework Equations E = \frac{mv^2}{2} = \frac{mq^4}{2(4\pi\epsilon_0)^2n^2\hbar^2} The Attempt at a Solution m = 9.11* 10^(-31) kg q = 1.6 * 10^(-19) C pi = 3.14 n = 1 hbar =...

Homework Statement A 12.0kg microwave oven is pushed 14.0m up the sloping surface of a loading ramp inclined at an angle 37 degrees above the horizontal, by a constant force F with a magnitude of 120N and acting parallel to the ramp. The coefficient of kinetic friction between the oven and the...

For the well shown below (Attachment or Link belew) solve the time independent one dimensional Schrodinger equation for energies less than V0. You may (and should) leave your answer in terms of a single transcendental equation for the allowed wave numbers. \frac{-\hbar^2}{2m} ...

Hi, let be a Hamiltonian so its energies satisfy E(n)=-E(-n) for every n >0 then my question is does this imply certain symmetry of potential ?? i believe that V(x)=-V(-x) so in absolute value positive and negative energies have the same value.

Hi all I was just looking through my notes from my first year of my degree, and I couldn't find a missing bit. I know that Planck's postulate states that the allowed energies of a quantum simple harmonic oscillator are 0, hf, 2hf etc and that by the Schroedinger equation, you get E(n)=(n+1/2)...

Homework Statement Two neutrons A and B are approaching each other along a common straight line. Each has a constant velocity v as measured in the laboratory. Show that the total energy of neutron B as observed in the rest frame of neutron A is given by...

Homework Statement Consider 10 He atoms as a system Thermodynamically, the state of maximum entropy hence the most likely macrostate for the system is 5 He to be excited and 5 in the ground state. But lower energies are more favourable so there should be more probability for the He to be in...

Edit: I believe this might be in the wrong forum, if it is I am sorry I don't know how to delete or move :( Hey guys quick question! I am studying basic radioactivity just for fun and ran into something that my text doesn't elaborate on. Could someone please clarify? The mass of...

Let's suppose we have a Hamiltonian of the form: \bold H =0 then it's obivious that if you want to get its energies you would get E_{n}=0 for every n, this is a non-sense since you must have positive energies (and a ground state) ...then if we "cheat" :rolleyes: and make: \bold H...

If we apply the Bohr-Sommerfeld quantization to GR (semiclassical) \oint_{S} \pi _{ab} dg_{ab}=\hbar (n+1/2) :confused: :confused: In this case if "Energies" (or whatever you call energy since in Quantum GR H=0 for the "Hamiltonian constraint" ) then using Einstein equation we see that...

a block is acted on by a spring with a constant k and a weak force of constant magnitude f. the block is pulled distance x0 from equilbrium and released. it oscillates many times and eventually comes to rest.(the block mass is M). 1)show that the decrease of amplitude is the same for each cycle...

I was wondering whether anyone was able to give me a hint on the following problem: Is the average kinetic energy of all particles in a gas hitting the sides of a container less, equal or more than 3/2kT? And if it is not equal how can you calculate the mean kinetic energy? I was...

Well, I'm working on a lab report for my general chemistry class, and we're supposed to answer questions on bond dissociation energies, but we never even discussed that during the lecture. I cannot find any information on it in my textbook, and I am really lost on how to answer these questions...

A simple harmonic oscillator has a total energy of E. (a) Determine the kinetic and potential energies when the displacement is three-fourths the amplitude. (Give your answer in terms of total energy E of the oscillator.) Kinetic energy ______________ x E <----(times E) Potential energy...

Why the energy eigen values for negetive energies are always discrete while that for positive energies are always continuous? Also what is oscillation theorem?

Rotational energies are in microwave region and vibrational are in infrered region, then how can the both be excited symultaneously? To excite vibrations we need infrared radiation then how can rotations be excited which are in microwave region?

hey where r my recent posts on orbital properties and electron energies?

A 100cm^3 box (1X10^-4 m^3) contains helium at a pressure of 2.0 atm and at a temperature of 100C (373K) It is placed in thermal contact with a 200cm^3 (2x10^-4 m^3) box containing argon at a pressure of 4.0atm and a temp. of 400C (673K) a) What is the initial thermal energy of each gas? b)...

Hi. I'm having some trouble trying to grasp a concept. I know that mathmatically Force perpendicular to motion is zero work. I can't seem to grasp this conceptually. First It seems That is an object is moving right and a force acts straight up on it, it will cause the object to move in a...

Let be the Hamiltonian: H=T+V where V(x)=A(x)+iB(x) then my question is if the Hamiltonian will have real energies..if we apply Ehrenfrest,s theorem for B: i\hbar{\frac{d<B>}{dt}}=<[B,H]> then if B is a function of x and x and p do not commute the derivative of <B> can not be zero...

Let,s suppose we have a qunatum system so the energies are the roots of the function f(x)=0..then my question is that we could calculate the roots to obtain E(0),E(1),E(2),...but the problem comes when we have the integral.. \int_0^{\infty}E(n)dn my question is if for this case we could...

How do you calculate the kinetic and potential energies of the Earth at the perihelion and aphelion? Given that the Earth's orbit is nearly circular GMm/R^2 = m(v^2)/R where M = sun's mass, m = Earth's R = orbital radius so v = √(GM/R) The kinetic energy, E, would be E =...

got a homework problem... What is the relationship between first ionization energies and metallic and non-metallic properties? no idea what they are talking about here.

Ok so i have 5 wavelengths of the rotational spectrum of a certain molecule. I need to find the moment of inertia. I have the equation down to I=(Hbar * wavelength)/(hc) Do i just use the shortest wavelength to figure out the moment of intertia? No radius was given.

+2Q and -Q two pt charges are r apart. AS no external agent exists, they attract to each other and each gains +Q/2 after conduction. Like charges repel. At same distance at r, 2*k(2Q)(-Q)/r = 2*k(Q/2)sq /r + 2 KE... but what i want to know is that when is the like charges repel...just after a...

Why is QCD non-perturbative at low energies? In QCD isn't the expansion parameter the fine structure constant? \alpha_s \approx \frac{1}{137} Does this somehow depend on energy, which wouldn't make sense to me. I cannot seem to find a good answer anywhere, so I thought I would ask here...

Hello there fellow physicist, Well for my A2 investigation I have done Thermocouples. I investigated the potential difference produced by different metal combinations. Now I need a hypothesis of some sort. What property of a metal will influence the potential difference produced by a...

A simple question: A small truck and a large truck have the same kinetic energies. Which truck has the greater momentum? Justify your answer.

A neutron at rest in the laboratory spontaneously decays into a proton, an electron, and a small essentially massless particle called a neutrino. Calculate the kinetic energy of the proton and the electron in each of the following cases: a) the neutrino has no kinetic energy b) the neutrino...

Particle A, at rest, decays into three or more particles: P1, P2, ..., Pn. Determine the maximum and minimum energies that P1 can have in such a decay, in terms of various masses. My solution: First of all, the decay should not occur if the rest mass of A would be smaller than the sum...

How would three P orbitals, X,Y,Z, in the same subshell, give the electrons different quantum energies?

The following is from a book I'm reading: (With regard to uncertainty and vacuums) can someone explain what's going on there.

Suppose you have a rail with two springs on the sides, both with the same constant K. The length of the rail is L, and the length of each spring is D (when not contracted or elongated). On that rail you have an object of mass M (which may be treated as a point particle), and the coefficient of...

if two particles have equal kenetic energies, do they have the same momentum?

What are the approximate relative sizes of the following energies? a) The n = 1 to n = 2 energy difference in hydrogen and the rest mass mc^2 of an electron b) The n = 1 to n = 2 energy difference in hydrogen and a typical fine structure splitting in hydrogen c) A typical fine...

How do you go about calculating the ionization energies from atoms? Electron affinities? (KJ/mol) for example, "Calculate the change in energy from the first and fourth ionization energies of Be?" Recently on a test (CHEM AP HIGH SCHOOL), I had a question similar to this on an exam. I...

Some time back a friend (PhD Nuclear Engineer), told me that the energies a neutron needed to form C14 from nitrogen were (and this is where my memory gets real fuzzy) around 15 MEV. Furthermore that neither nuclear explosions or the Sun produced neutrons of this energy. The implications were...

I wasn't sure where to put this post, it's mostly theoretical. Lately, I've begun some research. Mostly about the mind- not the brain. I believe that we as humans have some outstanding quality that distinguishes us from animals... and it is our minds. I'm very young, by the way, but I've...