What is Double slit: Definition and 825 Discussions
In modern physics, the double-slit experiment is a demonstration that light and matter can display characteristics of both classically defined waves and particles; moreover, it displays the fundamentally probabilistic nature of quantum mechanical phenomena. This type of experiment was first performed, using light, by Thomas Young in 1801, as a demonstration of the wave behavior of light. At that time it was thought that light consisted of either waves or particles. With the beginning of modern physics, about a hundred years later, it was realized that light could in fact show behavior characteristic of both waves and particles. In 1927, Davisson and Germer demonstrated that electrons show the same behavior, which was later extended to atoms and molecules. Thomas Young's experiment with light was part of classical physics long before the development of quantum mechanics and the concept of wave-particle duality. He believed it demonstrated that the wave theory of light was correct, and his experiment is sometimes referred to as Young's experiment or Young's slits.
The experiment belongs to a general class of "double path" experiments, in which a wave is split into two separate waves that later combine into a single wave. Changes in the path-lengths of both waves result in a phase shift, creating an interference pattern. Another version is the Mach–Zehnder interferometer, which splits the beam with a beam splitter.In the basic version of this experiment, a coherent light source, such as a laser beam, illuminates a plate pierced by two parallel slits, and the light passing through the slits is observed on a screen behind the plate. The wave nature of light causes the light waves passing through the two slits to interfere, producing bright and dark bands on the screen – a result that would not be expected if light consisted of classical particles. However, the light is always found to be absorbed at the screen at discrete points, as individual particles (not waves); the interference pattern appears via the varying density of these particle hits on the screen. Furthermore, versions of the experiment that include detectors at the slits find that each detected photon passes through one slit (as would a classical particle), and not through both slits (as would a wave). However, such experiments demonstrate that particles do not form the interference pattern if one detects which slit they pass through. These results demonstrate the principle of wave–particle duality.Other atomic-scale entities, such as electrons, are found to exhibit the same behavior when fired towards a double slit. Additionally, the detection of individual discrete impacts is observed to be inherently probabilistic, which is inexplicable using classical mechanics.The experiment can be done with entities much larger than electrons and photons, although it becomes more difficult as size increases. The largest entities for which the double-slit experiment has been performed were molecules that each comprised 2000 atoms (whose total mass was 25,000 atomic mass units).The double-slit experiment (and its variations) has become a classic for its clarity in expressing the central puzzles of quantum mechanics. Because it demonstrates the fundamental limitation of the ability of the observer to predict experimental results, Richard Feynman called it "a phenomenon which is impossible […] to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery [of quantum mechanics]."
Suppose an observer is moving at some constant velocity(<< c) and observing the young's double slit experiment. What changes will it observe compared to an observer at rest? This is what i could make out :
1) The wavelength of incoming light will change (doppler effect)
2) By the intuition...
Double slit experiment --WHAt is it it showing or proving
Im just not getting the general concept of what this experiment proves.
Please explain in very simple language --thanks!
Excuse me for patting myself on the back here but I just did my first successful double slit experiment. And it was easy! I poked 2 small holes in aluminum foil just as close as I could and shined my kid’s cheap red laser through them and Viola! I thought I needed razors and prisms and 2 lasers...
Hi guys, I am new to this site and would like to say a little about the double slit experiment.
I find the fact that the electrons or photons choose both paths unless being watched absolutely amazing. But what I find even more amazing to me is this:
The electrons, when fired at the screen one...
Homework Statement
A double slit is composed of two single slits. Each slit has a width of w = 0.01 mm and they are spaced s = 0.04 mm apart. Because the double slit is actually two single slits, the single slit diffraction pattern is superimposed over the double slit pattern and so some...
Has anyone heard of anyone trying to conduct the double slit experiment with a barrier between the two slits that goes all the way or near the detector?
If it could be done maybe it would be interesting to see the result.
It may answer the question if the photon (or electron) is interferring...
Gday, I am having some trouble with these questions becuase i was away for the two weeks when we did them any help or explanation would be greatly appreciated.
1) A transmitter drivest wo radio antenna A and B placed 2\lambda appart. Each atenna emit radio waves, in phase, uniformly in all...
I am reading The Elegant Universe by Brian Greene. It is really wonderful, however, I am confused by a section about Feynman's view on the double slit expiriment.
Greene writes:
"Feynman proclaimed that each electron that makes it through to the phosphorescent screen actually goes through...
the double slit interference experiment is set up and the fringes are displayed on screen. Then the whole apparatus is immersed in the nearest swimming pool. How does the fringe pattern change?? Which website I can get information?? Thanks.
Young's double slit experiment produces regular intervals of bright fringes and dark fringes. The bright fringes happen when the 2 sources of wave are in phase and superimpose while the dark fringes are produced when the 2 waves are in antiphase and vectorially cancel each other out.
However...
So I'm embarking through Brian Greene's magnificent book The Fabric of The Cosmos and in the quantum section he goes through the whole idea about how observation of a particle leads to collapse of the wavefunction into a definite location. He also uses the double slit experiment for photons and...
Two questions (I've got my AP Physics exam tmr :S)
1. What is the angular width of the the central maximum produced by a single slit of width 0.0011 cm if illuminated by blue light of a wavelength of 470 nm.
So I used Sin () = (m+0.5) lamda/w
2. What is the max. number of bright spots...
Have any experiments been conducted that explore the state of consciousness of the observer in the double slit experiment?
My understanding of the double slit experiment is this. Shoot one photon at a time through a slit and you get a line of light (particle model). Shoot single photons...
Homework Statement
A double-slit with a separation of 2.1 μm is used with white light. Find the angular width of the first
bright fringe between the violet (lviolet = 400 nm) and red (lred = 750 nm) end of the spectrum. (Assume
two significant digits.)
Homework Equations
What exactly...
It seems physicists have come to the conclusion that a single electron travels through both slits at the same time, otherwise there wouldn't be an interference pattern when only one electron is being sent through the apparatus. Apparently this experiment has been done in real life. You can't...
1. The photograph shows the interference pattern produced when monochromatic light falls on a pair of slits.
I cannot post links yet but the photo is of a typical fringe pattern produced by coherent light waves from a double slit.
Mark with an X on the photograph the fringe or fringes...
hey everybody, I am doing a physics project on the double slit experiment. (I know all the physics and math behind it so don't get into that stuff :P) I was just wondering if people had any suggestions on how to conduct the experiment, I was thinking of cutting two extremely small (knife blade)...
Hi
I would really appreciate if someone could answer what maybe a really simple question. I'm no physics expert but I do read a lot and I have a keen interest.
My question is related to light interference and the double slit experiment.
I know that by observing which slit a photon of...
This might sound very basic but...
when the electron passes through the two slits and we see the 'pretty' interference pattern on the opposite side what causes the dark fringes to be seen,
how does an electron, after acting as a wave and then as an electron when it is recieved, interfere with...
Homework Statement
http://img141.imageshack.us/img141/1395/40941671kx8.jpg
http://img141.imageshack.us/img141/982/82443157pt9.jpg
Homework Equations
http://img85.imageshack.us/img85/4523/60192566ie7.jpg
The Attempt at a Solution
I'm not sure where to start with this one. I've...
Hi. I'm preparing a research proposal for class and I've finally decided to do variations on the double slit experiment. What I'm looking at doing is performing the basic experiment using a red laser, just so I can make sure I have a good understanding of how to do it. Then I think I will test...
Hi,
I have a physics assignment which is asking me what the fringe pattern would look like if white light was passed through a double slit. Would it look like a single light which became gradually darker the further away it got from the central maximum?
Thanks in advance
Richard.
My apologies - you are all probably bored to death with these kind of naive questions - but I'd appreciate an answer if someone knows a definite answer.
I'm thinking about the original double slit experiment - We fire one particle at a time at two slits and, as long as we don't detect which...
I am stuck on a question regarding Young's Double Slit Experiment.
The two beams in Young's double slit experiment must
(a) be parallel
(b) have equal intensity
(c) come from the same source
(d) traverse equal distancesHere are my reasons for my answers. I may be misinterpreting certain parts...
While researching the double slit experiment and finding that even when only one photon is fired at a time and interference still occurs (so the photon must be traveling through both slits at once) i came up with a possible problem with the theory and wondered if anyone could help me see where...
Homework Statement
I am taking Young's Double slit expariment setup, however now I am changing the polarization. Below is the typical intensity when both slits have the same polarization, what I need to know is how the intensity graph changes when there is a difference of 90º and 180º in the...
Homework Statement
A laser with wavelength d/8 is shining light on a double slit with slit separation d. This results in an interference pattern on a screen a distance L away from the slits. We wish to shine a second laser, with a different wavelength, through the same slits.
What is the...
Hi there!
I'm currently sat in the lab working on one of my uni assignments (I'm in my second year at Exeter, UK), and I'm getting results that I just don't understand, so thought that someone here might know what's going on! :smile:
We're using a laser (through two lenses: I think one's...
A double-slit experiment is set up using a helium-neon laser (lambda =633nm) . Then a very thin piece of glass ( n=1.50 ) is placed over one of the slits. Afterward, the central point on the screen is occupied by what had been the m = 15.0 dark fringe. How thick is the glass?
I really need...
An Alternative Model of the
Double Slit Interference Experiment
W.H. Madden
November 20, 2007
ABSTRACT
This post presents an alternative model of the double-slit interference (DSI) experiment. The model is based on a novel physical interpretation of the concept of the DeBroglie...
[SOLVED] Double slit equations
In an experiment, blue light with a wavelength of 645 nm is shone through a double-slit and lands on a screen that is located 1.35 m from the slits. If the distance from the centre maximum to the 8th order bright fringe is 2.6 cm, calculate the distance between...
Q.Suppose that the the light rays in young's Double Slit experiment fall at an angle \theta=\sin^{-1}(\frac{\lambda}{2d}) .Then prove that the the Point P which is the symmetric point on screen between two slits is the centre of central minimum
Necessary Formulaes
for minima the waves...
i was going through the standard proof of Young's experiment using electric field concept .what the proof did is took two source S_{1} and S_{2} in the same line(asuuming such points do exist) and took a point P in the same plane as those points and found out the field at the point .
1.Was this...
Double split creates a wave interference pattern.
Closing up one slit creates a particle like pattern (all hitting one spot).
Does the closing up of one slit (allowing the particle to go through in only one narrow spot) measure its position (by the powers of Heisenburg Uncertainty Principle)...
hey during proof of expression of double slit interference at a point ,we take into account the interference due to 2 light rays emerging from 2 different slits. here why don't we account for the the interference also due to to light rays emerging from the same slit as in the single slit...
Homework Statement
A laser with wavelength d/8 is shining light on a double slit with slit separation 0.500 rm mm. This results in an interference pattern on a screen a distance L away from the slits. We wish to shine a second laser, with a different wavelength, through the same slits...
hi all...it is said that constructive interference happens when the path difference is nlambda and i think wavelength,frequency and amplitude of light going through both slits is the same then
why is the central maxima is the brightest spot?
why the brightness decreases when n increases...
Hello. Just to set things straight this is my first post here and I am also a complete nube when it comes to things this confusing. I started reading a book called "the elegant universe" by Brian Greene. So far I think the book is great but I am stumped on one part of the book. Its the part when...
I have a simple question on double slit experiment,
In double slit experiment, after the light rays pass through the slits, place two beam splitters (down converters) which split the light into two rays, one going towards the screen and other going orthogonal to it. Now my question is do we get...
Homework Statement
From "http://physicsweb.org/articles/world/15/9/1":
In 1909 Geoffrey Ingram (G I) Taylor conducted an experiment in which he showed that even the feeblest light source - equivalent to "a candle burning at a distance slightly exceeding a mile" - could lead to...
Hello, is it possible to reproduce the double slit experiment at home with some easily obtainable equipment?
I was thinking of using one of those laser pointers. Though I'm not sure how to make the slits - would cutting a pair of close lines in a piece of plastic with a sharp knife be good...
I came upon a very interesting article today:
http://www.msnbc.msn.com/id/19875410/site/newsweek/
I wanted to confirm what I read... this is the first time I ever heard of this kind of thing, and I was wondering if any of you have seen this before.
It talks about a tweak of Young's...
when performing a double slit experiment using photons it is said that if you fire individual photons that over time as more photons are fired the interference pattern starts to appear. My question is how do they define a single photon? what is the method that they can fire one photon at a time...
Hi
I don't know whether this is a homework-type question or not, so I am posting it here.
In young's double slit experiment the interference pattern is found to have an intensity ratio between bright and dark fringes as 9. What does this imply:
(Below are the options provided in the book...
I was watching a video about Quantum Mechanics and the double slit experiment which shows electrons to be both a wave and a particle, though not at the same time. I had learned this earlier in high school, though at that time did not understand the importance of this. Now I do and would like to...
Hi,
We all know that when we shoot electrons one by one on an apparatus having two slits then it forms a interference pattern. Means this implies that the electron passes through both the slits at the same time
Now when we keep a detector near the slits to watch the...
I am doing a presentation for my high school physics class on light. I want to show the wave-particle duality of light, but first I want to show each separately. So I want to introduce Young's Double Slit Experiment to show the wave nature of light.
The problem is... I apparently don't know...
If you take the normal double slit experiment but shine light on one of the slits so that it's possible to tell which slit each electron went through (by detecting scattered photons) then the "fringes" disappear amd you get constant light. If before the scattered photons hit the photon detector...