Quantum physics Definition and 728 Threads

As a novice to Quantum physics and as a working physicist in the oil industry this may be a stupid question but I find the whole subject of quantum physics fascinating. I have been pondering the missing mass in the universe and particle vs wave argument and came across a nice description...

Homework Statement Hi I am new to this forum and offering quantum physics at A level. Can anybody help with the following problem: The rest energy of an electron is 0.511MeV. A positron created in a cloud chamber has 0.158MeV of kinetic energy. It collides with an electron at rest...

Hello all, I have a quantum physics question which is more conceptual and mathematical than anything. Here's the question: Explain why ψ and its derivative have to be continuous and finite.

I'm doing the frank hertz experiment and in preparation I'm trying to get a few questions answered. any help would be greatly appreciated, 8. Considering that the energy of the 1st excited state of the mercury atom is ~4.8eV above that of the ground state, what is the maximum amount of...

I'm doing the frank hertz experiment and in preparation I'm trying to get a few questions answered. any help would be greatly appreciated, 8. Considering that the energy of the 1st excited state of the mercury atom is ~4.8eV above that of the ground state, what is the maximum amount of energy...

Homework Statement Find the ratio of Rayleigh-Jeans and Planck densities of radiation at the maximum for a black body at T = 5000 K. Find the frequency of the radiation maximum of a black body at T=3000 K. What part of the electromagnetic radion spectrum does this frequency belong to...

Hi, I'm new here and I apologise in advance for any perceived abruptness and hope I am not causing offence :) I am debating a guy, religious philosophy type, who claims that virtual and real universes would be indistinguishable from each other ... to some degree I suppose that is true i.e...

Hi there, you know there are simple mathematical calculations, rather based on arithmetic properties (module, commensurability, etc), that manage to render (pseudo)random number sequences. You have to be familiarized with some properties and characters of waves I'm going to refer here (no sh*t...

http://www-physics.lbl.gov/~stapp/PTRS.pdf Just thought I'd leave this here to start a discussion. Not sure if the thread will need to be moved.

Hello everyone. I am new here so let me say what I said in my first post first... Hello everyone, before I start, I just want to say I’m a little out of place here. I am not a student of physics or cosmology, and I am definitely not a professional at anything scientific. I am an artist and...

Hello i am new to forum, and relatively new to Quantum physics study. I know that Quantum Physics cannot explain all the physical or universal phenomena, BUT: Provided that gravitational fields are weak, and we have to do with phenomena at low energies , so that the distortion of space and...

Some days ago, a professor in physics recommended a book on Quantum Physics to me. It's quite a popular book ,he'd said. But I conviniently forgot the name! All I remember is the first three letters of the name of the author, they are "BIE" and there is an "s" somewhere(which the professor...

Homework Statement This is a problem I did during a test, and I am looking it over to see what I did wrong.. 1. An Electron is accelerated by a potential difference of 75V. What is the de Broglie wavelength Homework Equations P = h/λ Ek = 1/2mv^2 eV = 1.6E-19 The Attempt at a...

Hello! High school physics student here. I have some quantum physics questions for you. I am currently doing various studies through Wikipedia right now over quantum physics and I find it extremely fascinating, but I am a bit confused when it comes to the quantum probability areas. The...

hi. I'm relatively (no pun intended) new to quantum physics. I just finished my high school physics class which mainly dealt with the basics and classical physics. Can anyone suggest some papers or articles I can read in order to get my feet wet in this new realm? Thanks.

Calculate the highest frequency X-rays produced by 8.00 · 104 ev electrons. 2.0 x 10 19 HZ My teacher states it is wrong. This is on the final exam. I need help.

So we had a thread about the FQXi essay contest a couple weeks back, and when I first saw the winners list this one... ...jumped out at me, both because the inclusion of the word "undecidability" indicated the paper might actually touch on matters (i.e. formal logic) I feel qualified to...

Homework Statement Estimate the size of the fine structure of the 2p conguration in hydrogen-like sodium (i.e. sodium ions with all but the last electron removed). Why can't we use perturbation theory to calculate the effect of the spin-orbit interaction in hydrogen-like uranium...

I'm a grade 10 student and very much interested in physics. Just wondering the difference between quantum mechanics and quantum physics. Are they synonyms? What would you expect to study in quantum physics and quantum mechanics? Help please..

Homework Statement The distance between two slits is 0.05mm and the distance to the screen is 2.5m. What is the spacing between the central bright fringe and the first-order fringe? Use yellow light with a wavelength of 580nm Homework Equations xm=mλL/d The Attempt at a Solution...

Hi, as my previous thread was closed, I'd like to continue asking some questions here regarding QM (of course if the mentors don't mind that ?). So, has entanglement been experimentally proven?.

I have taken several classical physics courses and am now interested in expanding my knowledge of the field during my personal time. I am therefore wondering if anyone has recommendations for a good math based quantum physics text to introduce me to the branch of quantum mechanics. I do not...

I have only completed the intro sequence to physics, but next semester I really want to take quantum for various financial and time reasons. Anyway, I will be taking it alongside Vibrations and waves (physics 3) and differential equations. Will I be prepared? Most people seem to take Modern...

Guys help me to find some clearly written books about quantum physics please... Before thanks!

Homework Statement The American physicist Robert A. Millikan (1868-1953) won the 1923 Nobel Prize in physics, in part for his work on the photoelectric effect. Assume that Millikan observed for a hypothetical metal a maximum kinetic energy of 0.535 eV when electrons were ejected with 431.7 nm...

Homework Statement I have another question, An incandescent light bulb consuming 75 W emits only 5% of this energy as visible light of wavelength 597 nm; the frequency of the emitted light is 5.02e+14 Hz. How many photons per second of this light does the bulb emit? Homework Equations...

Homework Statement A pulsed dye laser emits light of wavelength 576 nm in pulses of 456 µs duration. This light is absorbed by the hemoglobin in the blood and can therefore be used to remove vascular lesions, such as certain blemishes and birthmarks. To get an estimate for the power required...

Homework Statement Hi all i am doing past exam paper questions and this question i am not sure about, i check notes and books but can't find relevant information Q1i.) If we try to confine an electron in a small region of size a, then this electron has to have a non-sero average kinetic...

Homework Statement A tritium atom is in the ground state and undergoes beta emission, creating a positively charged Helium ion. Assuming the nuclear change is instantaneous and there are no recoil effects, calculate the probability that the Helium ion will be found in its ground state...

you see i love quantum physics its a new discovery for me but i don't know i just get it. it amazes and baffles me( as anyone who is not confused by quantum physics truly doesn't understand it) i alwways had liked math but never science but always did and still do love the study of space and the...

Hi, I just finished up a Complex Analysis course last term and, though I'm no physics major, I thought Quantum Physics looked interesting. Does anyone know some common or interesting applications of Complex Analysis within Quantum Physics? Or even an online resource that might delve into...

Is the expectation value of momentum/position/energy the value that we're most likely to measure? So suppose we measure 100 particles with the same wavefunction, would we expect most of them to have momentum/position/energy that's equal to the expectation value? And I was wondering, how do we...

Homework Statement Wavefunction = (2/L)^(1/2) * sin(2*pi*x/L) exp(−i2*pi^2*h_bar*t/mL^2) I calculated the expectation value of momentum to be 0, and expectation value of kinetic energy to be 2*pi^2*h_bar/mL^2 (also found to be it's definite K.E) Using the momentum operator, the...

Hi there, I have some questions which I cannot solve from my Quantum book. I would appretiate some hints as to how they should be solved. Thanks.

then i want to know how to prove E=hf without any assumption but with our basic physics knowledge to prove the formula is actually explaining quantum physics theory....i still blur about the formula for quantum physics...thanks if someone help me out!

Homework Statement Hi, I've been given a problem set and there is suddenly new notation that I've never seen. Can anyone shed any light on what this means: "Treating a0 as a parameter, write down the complete wavefunctions (including radial and angular parts) for the states 1s, 2s, and 2p...

So I'm looking at my notes, and there's a section on annihilation. It explains that in a particle/ anti-particle collision, momentum is conserved. In the problem, an electron with velocity= 8 x 10^6 m/s collides with a positron with velocity 3 x 10^6 m/s, producing two photons. The equation was...

Homework Statement ok so i know whenever a photon is absorbed it will jump up a energy level and when it is emmited it releases energy. but my question is, for example, if k=1 (fundamental state) in a hydrogen atom and they give you the given wavelength of the photon, you solve it and you...

Homework Statement A photon with λ = 600 nm interacts with a hydrogen atom in fundamental state. Will the photon be absorbed? Justify your answer. Homework Equations hc/lambda= energy of photon 1/lambda= R(1/2^2-1/n^2) (visible light) c= speed of light lambda= wavelength h=...

Hi, I am an Electrical and computer engineer. I recently decided to start studying physics in my spare time in the futile attempt to understand the universe, or at least parts and interpretations of it. I decided to start with quantum physics, a book called "Quantum Theory" by David Bohm. It...

Homework Statement What is the de Broglie wavelength of an electron that has been accelerated through a potential difference of 1 MV ( you must use the relativistic mass and energy expressions at this high energy.) ans. 8.7 x 10^-13 Homework Equations M= Mo/ square root (1 - v^2/c^2)The...

So, EPR shows that once something like the spin of a particle is determined, the wave function of a particle can be collapsed instantaneously but i have a question about this. Say there is an observer on a planet 5 light years away from you (you are on earth) and he makes an observation that...

1) when light of wavelength 2.08*10^-7m falls on a photosurface, a voltage of 1.40V is required to stop the emitted electrons from reaching the anode. What is the largest wavelength of light that will result in emission of electrons from this photosurface? 2) To determine the work function...

Hello there! I am a new member of Physics Forums, glad to have found you these days! I am a High School (Lyceum) student in Greece, 16,5 years old and I want to know if there are any books (preferably in pdf form) that I can find and buy, that refer to basic Mathematics about Quantum Physics...

the chapter of quantum physics vs classical physics will be one of the topic that i will be tested in final exam,but I'm a little confused by them..so i need a good references to refer to..could you please recommend me some good website as i can refer to..i have found this...

I recently had a idea after watching nova's special on mendel fractals. I support a string theory as well as M theory. Just like most of us nerds we all want the unified equation that einstein sought after till his last days. Recently fractals were used to describe heart beat's. What was...

is there any video lectures source which is about statistical physics or quantum physics like MIT Lectures. I found some lectures about quantum physics but these are only related with it and it couldn't be considered as essential source.

"Randomness" in Quantum Physics I am interested in whether "randomness" actually exists in physics. I'm not very familiar with the math involved, but I understand that some quantum theories (one in particular that was created by Richard Feynman that uses canceled infinities) and also the...

If I want to calculate <x> of an electron that is in a state described by \psi (x,t)=\frac{1}{\sqrt{2}}[\psi_{0}(x,t) + \psi_{1}(x,t)]] where \psi_{0} and \psi_{1} are the two lowest energy states of an electron in a one dimensional box, can I then simply calculate <x> for...

I thought this 'd be interesting http://www.sciencedaily.com/releases/2008/10/081010081650.htm Mathematicians Illuminate Deep Connection Between Classical And Quantum Physics ScienceDaily (Oct. 17, 2008) — In a seminar co-organized by Stanford University and the American Institute of...