# What is Slit: Definition and 1000 Discussions

A slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. It is used in conjunction with a biomicroscope. The lamp facilitates an examination of the anterior segment and posterior segment of the human eye, which includes the eyelid, sclera, conjunctiva, iris, natural crystalline lens, and cornea. The binocular slit-lamp examination provides a stereoscopic magnified view of the eye structures in detail, enabling anatomical diagnoses to be made for a variety of eye conditions. A second, hand-held lens is used to examine the retina.

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1. ### B What is causing destructive interference in double slit experiment?

When you do the double slit experiment with photons or electrons you get a wave pattern. At certain points no electrons are detected. This is said to be caused by destructive interference. Destructive interference of what? If we shoot single electrons, one at a time, from where is this...
2. ### I Amplitude of the maximums in single slit diffraction

Hello! I was trying to calculate the amplitude of the secondary maximums in the single slit diffraction. When I use the formula: $$I = I_0 (\frac {sin(\Delta \phi /2)} {\Delta \phi /2})^2$$ If I take ## x = \Delta \phi /2 ## and derivate I get that the maximum occurs when: $$x = tan(x)$$...
3. ### I Observer effect in the Dual Slit experiment

How detectors/observers in front of each slit works , does it somehow disturb with electron/photon? Does photon/electron must pass through detector/observer, so maybe his internal parts change final result on screen into just two lines?
4. ### A Two Slit Interference Experiment Variations

Examples that have references to special two slit experiments : https://sciencedemonstrations.fas.harvard.edu/presentations/single-photon-interference https://en.wikipedia.org/wiki/Double-slit_experiment If you have an opinion on what you think the experiments tend to support and what they do...
5. ### A Can the double slit experiment distinguish between QM interpretations?

This paper claims that the double slit experiment can be used to distinguish between QM interpretations: https://arxiv.org/abs/2301.02641 IMO, the paper goes astray right at the start, when it points out that time is a parameter in the Schrodinger equation, not an operator, so that equation...
6. ### I Double Slit Experiment Mathematics

Electrons are shot thru two slits separated by a distance s at a screen a distance ##z_0## away. The wave function for the particles is proportional to ## e^{ik \sqrt{(x-s/2)^2+z_0^2}} +e^{ik \sqrt{(x+s/2)^2+z_0^2}}## Taking the first one, we can manipulate the square root algebraically...
7. ### B Non-parallel double slit experiment

Is it possible to tell which slit some of the light went through when the slits aren’t parallel (green & red boxes in option 3)? I used a Bahtinov mask to cover the aperture of my 600mm f/9 lens while observing the star Polaris. Various open slits were tested while others were covered with...
8. ### I Double-slit experiment, determining which slit an electron passed thru

I was reading Feynman's lecture on the double-slit experiment, the attempts to determine which slit an electron passes through. https://www.feynmanlectures.caltech.edu/III_01.html#Ch1-S6 And the key part is when Feynman says, "Then a terrible thing happens.", about the low optical resolutions...
9. ### I Does the photon in a double slit experiment create many worlds?

I can't find the anwer on this anywhere, so I hope I may ask it here. My question: In a standard double slit experiment, according to the Many Worlds Interpretation, does the photon create different worlds with different impact locations of the photon? So, without measuring which way...
10. ### I Young's slit experiment with single photons

Hello, I have a little problem understanding Young's slit experiment with single photons : I have understood for a long time that each photon impact on the screen corresponds to a photon sent by the source, and that, if we don't try to find out by which path the photon has passed, of course...
11. ### B Double slit experiment combined with Stern-Gerlach

A bit of background: I've read Derive the probability of spin at arbitrary angle is cos( ) | Physics Forums post in this forum and went into a "thought rabbit hole". It didn't make any sense to me and I think I made a wrong assumption somewhere along the way. Instead of typing everything out, I...
12. ### Single Slit Interference Pattern: Increased Distance

ATTEMPT AT SOLUTION The effect on the pattern when the screen is moved further away is the bright fringes would become wider, the light intensity of the bright fringes would decrease, and the bright fringes will appear closer together. REASONING I answered this question based on how light...
13. ### A A double slit thought experiment leading to a paradox

Consider a Double Slits experiment in which the light source is monochromatic and each slit very narrow. There will be many fringes visible on either side of the axis. 1) If the light source is pulsed with very short, randomly spaced, pulses it will produce spectrally broadened radiation and...
14. ### Two slit interference: new intensity after doubling width

Here is the solution, I understand how they got E, but I don’t see how they could get E’ from cosine addition formulas? I don’t need to know how to do it with complex numbers.
15. ### I Uncertainty in an experiment with an image viewed through a big slit

This is a simple experiment that demonstrates how it is possible to draw conclusions similar to those of quantum physics, without having to "invade" the microscopic world. A student is led into a windowless room, which has only a slit in the ceiling. The light that passes through the slit is...
16. ### A Double double slit experiment and path information

Hi Pfq My question is about this experiment: https://www.nature.com/articles/s41598-020-68181-1 (the link was given by DrChinese. If all the impacts are conserved no interference can be seen on the screens. but if we only take the impacts (Y, yi) where Y is always at the same position on the...
17. ### I Young's Double Slit Experiment: Is it Possible?

I think that it is harder to describe the two slits Young experiment in terms of hamiltonian because the particle has a constraint: to pass through the slits. is it possible? thanks.
18. ### B Q - Double slit experiment, delayed slit selection observation

Do I see an interference pattern on a interference screen in Double slit experiment if there is a detector watching which slit photon went trough but the observer does not see the result of detector measurement? Thanks :]
19. ### I Significance of double slit experiment?

What is the significance of the double slit experiment? When I first learned about it I thought the human observer decided the outcome. But I guess a human observer isn't even needed and therefore a conscious mind is just as irrelevant. What does it prove that an outcome is neither one thing or...
20. ### I Does the double slit experiment show waves collapse when observed?

Do wavefunctions collapse when looked at? Or does observe mean something else? https://www.nature.com/articles/d41586-018-05892-6 This article is where my information is from, physicists talking about how our mind causes the collapse.
21. ### I Double slit fringe visibility with sunlight

Hi Pfs, I know that Young made his double slits experiment with sunlight and i would like to know the best value of the fringe visibility on the screen. The visibility is equal to (Imax - Imin)/(Imax + Imin) thanks
22. ### I Calculating Intensity in Single Slit Diffraction Experiments

In a single slit diffraction experiment, when we want to calculate the intensity of light on a screen located very far away from the slit, usually Huygens' principle is adopted as a model to perform the calculations. It is assumed that the width of the slit consists of an infinite number of...
23. ### B Double slit -- simple question

With the double slit experiment the first thing I have to ask that is never explained, is why would an electron not always go through one slit? One does not design a gun to fire randomly over an area, but to be fairly precise and accurate in it's firing. Is there an assumption of the firing...
24. ### Derivation of single slit diffraction formula

I want to ask several questions regarding to the text: 1) Why do we find the minima of the diffraction? Why not the maxima?2) "Figure 25.32b shows two rays that represent the propagation of two wavelets: one from the top edge of the slit and one from exactly halfway down" Why do we take point...
25. ### I David Deutsch's Many Worlds Interpretation and the Double Slit Experiment

David Deutsch is a well known proponent of the Many Worlds Interpretation. His argument seems to be that a single photon in the double slit experiment must be interfering with one from another world. It is commonly held by physicists that the the photon, as a wave going through double slits, can...
26. ### I Math of Electron Double Slit Experiment

I'm looking for a good derivation of the "wave" patterns in this experiment. I suppose that if wave-particle duality is an obsolete idea, there must be a derivation from quantum mechanics that gets close results. Thanks in advance
27. ### B Question re photons/EM waves and the double slit experiment

Not a physicist. Background is in electronics over many years. Have recently been "binge" watching youtube lectures on the "dreaded" QUANTUM MECHANICS by various people(Susskind, Feynman et al) and trying to comprehend the whole thing. While I can generally follow the lectures I must admit the...
28. ### B Double Double Slit Experiment -- Question about Variations

emitter -> double slit -> double slit -> detector. Was an experiment ever made where two double slits are placed at some distance between each other? What kind of interference pattern would you get? What would happen if second slits were placed at the position where there is destructive...
29. ### I Interference Patterns & Photon Paths: Exploring the Double Slit Experiment

Hi. As i understand in double slit experiment photon can arrive at slits through different paths (longer and shorter) and it would still show interference pattern. My question is - if there was some path cutting device in a way of photon (on longest path after length that photon arrive at...
30. ### Finding Color of Two Lights Given Slit Source & Screen Distance

Given values : - Distance between the slit source and the screen L - d1,d2 The problem is to detemine the color of the two lights
31. ### I Double slit - properties of slit?

In the double slit experiment, are there articles that study different slit properties (e.g. charges, magnetic fields, current, etc.)? Curious if a wave is the property of the measurement, changing the properties of the experiment may alter the output measurement.
32. ### B View double slit from other end

Our eyes not only detect the visible spectrum of light; they can also show the direction the photons are coming from. If, instead of a detecting screen, we use a moving camera or an array of cameras, can't we tell exactly which slit a photon / electron passed through?When viewing a light source...
33. ### B Double Slit & Quantum Eraser

If you perform a double slit experiment but never look at the results could we say that the experiment never actually happened? The beginning of the experiment would show intention to find results but we believe intention does not create physical reality. Quantum Eraser could be preventing us...
34. ### Destructive interference through a narrow slit

So I thought angle=wavelength/width of slit But when I solve for the width I got the wrong answer of 4567 nm, when the answer is suppose to be 130881 nm. I figured out that I needed to multiply my incorrect answer by 28.7, but where does this constant come from? Its not part of the equation...
35. ### What is the effect on a diffraction pattern when reducing the width of the slit?

Monochromatic light is normally incident on a diffraction grating. The mth order line is at an angle of diffraction angle θ and has width w. A wide single slit is now placed in front of the grating and its width is then slowly reduced. As a result: A. both θ and w increase B. both θ and w...
36. ### Angular Width Question in Single Slit Diffraction

i feel like subbing the numbers into the equation isn't enough because of the second minima and maxima thing? not sure what to do... would appreciate any help.
37. ### B How is the measurement done for the double slit experiment?

How is the measurement of which path the particle took done for the double slit experiment? When electrons are being sent through the slit. Or when photons are being sent through the slit. Is it an active process or a passive process? I haven't seen an explanation for this and perhaps this...
38. ### Can Small Errors in Path Difference Affect Double Slit Interference Patterns?

$$Δφ = 2π \frac{L_2 - L_1}{λ}$$ $$Δφ = 2π \frac{\sqrt{0.016^2+10^2}-\sqrt{0.014^2+10^2}}{560*10^{-9}}$$ $$Δφ = 33.659 rad$$Answer = 2.24 rad (unsure if the answer provided is correct/wrong)
39. ### I The Ensemble Interpretation and the Double Slit Experiment

I am a big fan of Ballentine's book on QM and was reading the discussions about the Ensemble Interpretation. Although, I am not an expert on these matters I reject the idea of the wave function collapse as a fundamental postulate of QM. Instead, I've come to the conclusion that we don't...
40. ### B Double slit question - how far apart can the slits be?

How far apart can the slits be and the double slit experiment still works i.e the wave interference pattern is seen on the target screen?
41. ### B Questions about double slit experiments

Firstly I’m just an interested layman who only started delving into QM and physics later on on life. So please forgive my ignorance. One of the things I’m trying to understand better is the wave / particle duality nature of objects. In the classical set up where single electrons are fired one...
42. ### B Double slit experiment with electrons

Hi, Could you please help me with the queries below? Thanks in advance! Question 1: I was watching this video. Between 8:36 to 9:44 the following is said: "But only firing particle by single particle at this barrier with the 2 openings and by recording dot by single dot where each of those...
43. ### B Gravitational signature of a photon in a double slit experiment

I'm trying to think of a how the double slit experiment can detect a photon without interacting with it in theory. In principal (not reality of course) does a photon have a gravitational signature which could be used to detect which slit it traveled through during the double slit experiment...
44. ### I Why find the highest order maxima/minima in slit equations?

I have been seeing interference and diffraction problems involving the double slit and single slit equations that ask for things like the "highest order maxima" or minima, which I have learned are basically found by setting the angle to 90 degrees. My question is are there any real world...
45. ### I The velocity of Pilot-wave and the Double slit experiment

Hello, Its been a while since I'm trying to understand the concept of the pilot wave theory and it's relation with the deBroglie wave. What is the fundamental difference between the two? My confusion comes from the double slit experiment. The velocity of the deBroglie wave is c^2/v so I...
46. ### I Double slit experiment and the Uncertainty Principle

With the double slit, experiment we show the double nature of light and matter as wave and particle. In particular, the so called "which way" thought experiment illustrate the complementary principle. In my book, this experiment is analyzed putting a series of particles in front of one of the...
47. ### I Quantum vs Classical multiphoton interference on double slit

For a setup analogous to double-slit experiment, do I understand it correctly that if we have two photons, one going only through slit A and another going only through slit B simultaneously (or vice versa as they have a symmetrical wave function), then there will be no interference pattern...
48. ### B Dual slit with controlled electron trajectories

In the traditional single electron duel slit experiment, I assume a cathode emits electrons in an unfocused direction spreading across the dual slits like a flashlight beam, but one electron at a time. Electrons however can be finely focused and controlled using magnetic or electric fields...
49. ### Trying to make sense of the double slit "experiment"

How did you find PF?: A quick Google search of Physics forum gave me a link to this site. I have a good background in science (BSC Mathematics), but not specifically in Quantum theory. That happened after I left University. I have read lots, know a fair bit but wouldn't dare to claim I...
50. ### B What is the pattern in a double slit experiment near the slits?

I am looking to this picture https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory#Double-slit_experiment it seems that fringes only appear on a screen when it is not too close to the fringes. and that the electron near the screen would give a pattern as when the path is known. Is it right?