What is Interference: Definition and 999 Discussions

In physics, interference is a phenomenon in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude. Constructive and destructive interference result from the interaction of waves that are correlated or coherent with each other, either because they come from the same source or because they have the same or nearly the same frequency. Interference effects can be observed with all types of waves, for example, light, radio, acoustic, surface water waves, gravity waves, or matter waves. The resulting images or graphs are called interferograms.

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  1. R

    How does electromagnetic interference work?

    I have to do a presentation on why cellphones are banned in hospitals, and I'm going to have to explain how electromagnetic interference from the waves a cellphone gives off can mess with medical equipment. Can someone please explain the physics behind this?
  2. Z

    Double Slit - any interference?

    Homework Statement Can wave-like behaviour, eg interference or diffraction, be observed with the following? Electrons with a velocity of 20 m/s passing through a double slit with a separation of 2nmHomework Equations The Attempt at a Solution The solution is given in the book. λ = 2.65 x...
  3. S

    Is single particle interference explainable via entanglement?

    Do you think that: Single particle interference is explainable via entanglement? For example: in the single particle double slit experiment
  4. A

    Interference by amplitude division (double reflection) for wedges

    Homework Statement Transparent wax of refractive index n=1.3 is deposited on top of a glass plate of width 1cm and refractive index n=1.5. The thickness of the wax is 0.01mm at one end of the plate and tapers uniformly to zero at the other end of the plate, which is defined to be at x=0. At...
  5. D

    Sound wave interference destructive interference problem?

    Homework Statement Two identical loud speakers placed at A and B 2m apart produce sound waves of frequency 440 HZ and with a velocity 320 m/sec a small microphone was used and placed at C along a perpendicular line from AB if there will be a destructive interference at C find the length of...
  6. P

    Can double slit interference be explained by the influence of previous photons?

    The usual interpretation of the double slit experiment, when done with a single photon at a time, is that the photon must interfere with itself. However interference cannot be measured in a single-photon experiment - it requires a large number of photons to manifest a discernible interference...
  7. T

    Determining interference pattern for two loudspeakers

    Homework Statement Two loudspeakers, at the same height are 2m apart and in phase with each other.Both emit 705Hz sound waves into a room. A listener stands 5m in front of the loudspeakers and 2m to one side of the centre. a) Is the interference pattern at this point...
  8. S

    Dual particle and dual double slit interference

    In short the question I am trying to answer is: 1. do the "waves-functions" from separate particle interfere? 2. do the Schrodinger equations predict the interference pattern caused by the interference of the "wave functions" of two separate particles? The above question is...
  9. T

    Why do light form an interference pattern when passing through only one slit?

    Hi guys, i know that if we were to have one water wave passing through two slit, an interference pattern would be form. However, i am still unclear of the kind of the pattern that will be form when a single water wave were to pass through a single slit. Will it form an interference pattern too...
  10. H

    Find the point of destructive interference of two waves.

    Homework Statement Two coherent in-phase point sources of sound are located at the points (-2 m, 0 m) and (2 m, 0 m). If the wavelength of the sound is 0.9 m, at which of the following x values on the x-axis does destructive interference occur? Homework Equations Wave Equation: y(x...
  11. B

    Is there a standard calculation for interference fit bushings on aluminum tubes?

    Hi. I have aluminium tube (Alloy 6063T6 ) 1 1/2 inch outside diameter 1/4wt. I need to turn inside of this tube to take a 30mm outside diameter suspension bush interference fit . Is there a standard calculation for the diameter of 'receiving' holes for interference fit bushes?
  12. F

    Interference - Q done, is it right?

    Hi all, I have a question here that I've done but it hasn't got an answer provided. I'm sure it's easy stuff but haven't looked at this material in a while so just want to double check. (The things in red are what I added to the original diagram) RE-DONE d = √17 d + λ/2 = 2√5...
  13. S

    Effect of phase difference on interference pattern

    When two wave functions are in perfect phase = constructive interference when the phase difference is half (the wavelength) = destructive interference What happens when the phase difference is more than one wavelength in case of: Case 1: single particle interference Case 2: two-photon...
  14. M

    Interference from Van De Graff

    Hello all I really hope someone can shed some light on a problem I'm having. I'm currently researching granular fluid behavior in High voltage electric fields. My setup is essentially a 200kV generator placed directly under a glass container with my test medium inside of it. The...
  15. R

    Faraday Cage Applied to Power Lines to Negate Field Interference

    Hello learned Engineers, Physicists, and people more useful than myself: Thank you in advance for reading. I would like to submit a more educated proposal to a utility company for a method that would allow it to install 500 kilovolt renewable power transmission lines through many residential...
  16. P

    Interference of Waves in a Pool: Still Surface & Heating Effects

    I'm trying to increase my understanding of what happens to waves with interference so I'll ask the following question to try and do so. If one had a pool of water with a wave machine pulling the side in and out all along one side and an identical wave machine on the other side working in...
  17. P

    Could Interference be used to effect one way radiation?

    If you have radiation from two black body sources at same temperature will they make a maximin minimum Interference pattern that another small black body sphere can be inserted in, in a minimum space. Will they radiate low radiation to the sphere (Due to the radiation energy in that area been...
  18. J

    Interference pattern from a plano-concave lens

    Hello. I need some sort of explanation. I was unsuccessfully trying to find information on the web and derivation by hand seems rather complicated for me. So I have a such set-up: HeNe laser ->> plano-concave lense )], light is incident by some angle (NON 0°). then looking to reflection...
  19. jaumzaum

    Young's light interference experiment

    Why, in the Young's double slit light interference experiment, the medium fringe is the brightest and the other ones go reducing its bright as you moves away the center, if they all suffer the same constructive interference. Please explain this to me, I have this doubt it's been a month and...
  20. A

    Constructive Interference of Sound waves

    Homework Statement A pair of speakers connected to the same signal generator face each other, one at x=0 and the other at x=1.5m. If they are producing a sound frequency of 2000Hz what are the points (position x) of constructive interference between the speakers? Express your answer in...
  21. R

    Sound interference True/False

    Homework Statement Consider two sources of sound, each of which emits a sound wave of the SAME frequency and the SAME intensity. The sources are located on a straight and level road, relatively close to each other. You, the listener, are also located on this road, about 1/4 mile away from the...
  22. S

    Blocking terrestrial interference possible or not?

    Hello everyone. I am a mechanical engineer but I have a question which I hope someone can provide me some info. I was interested to know whether it is possible to block signals by creating a magnetic field or not. I'm asking this question because some people live in places which have a lot...
  23. F

    Interference of electromagnetic waves

    I haven't been able to find any literature that answers this question in a pleasing way. Also, all sources on the internet are contradictory. If electromagnetic waves (out of phase since they are emitted by the gaseous atoms in discharge tube) sent through a diffraction gitter interfered with...
  24. A

    Question about a modified delayed choice quantum eraser. 2nd order interference?

    OK, a quick intro to the delayed choice quantum eraser is at wikipedia (http://en.wikipedia.org/wiki/Delayed...quantum_eraser ). I have attached a figure of the modified DCQE. In this setup there is no delay, there is no choice, and there is recombination of the idlers instead. In the...
  25. B

    Question about the destructive interference of radiation.

    If two radiation signals cancel each other out through destructive interference, is it still possible for a material to absorb energy and heat up when exposed to the two radiation signals?
  26. K

    Double slit interference with single pencil lead?

    Hi guys, Was trying out a home made double slit experiment as I've seen on youtube with a laser pointer and 2 pieces of pencil lead. Then I realized that I can obtain the same interference pattern with the single pencil lead. Is this equivalent to a double slit interference?
  27. B

    Question about solar interference on laser tag guns

    So my brother had a birthday party the other day where this company that rents laser tag guns comes over and all his friends played a big game of laser tag outside. the guns worked surprisingly well, and there was even a "grenade" that would shoot lasers out in all directions once a pin was...
  28. X

    Single Electron D-slit Interference Experiment

    In the two well referenced experiments [1, 2] that claimed to have observed double slit interference pattern of SINGLE electron, the central claim is that there could not have been more than ONE electron present at the same time in the apparatus (or such probability is negligible). However...
  29. D

    Cathode ray create interference pattern?

    If I were to construct a cathode ray tube in which the beam of electrons was focused on a double slit, behind which was a screen of phosphorous, could I create an interference pattern? Could this setup be made at home? I imagine making the slits would be the most difficult part. Or is this...
  30. A

    Two source interference determining wavelength

    Homework Statement A laser with wavelength d/8 is shining light on a double slit with slit separation 0.300 . 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...
  31. S

    Exploring Light Interference: The Effect of Slits and Gratings on Light Patterns

    When you shine light through a diffraction grating/double slit/single slit, I understand that you see an interference/diffraction pattern on the wall, so that you have: light source -- grating/slit ---pattern on wall But if you put a grating/slits between your eyes and a light source, why do...
  32. F

    Interference of a bunch of incident electromagnetic waves

    Hi There is lots of text, but it is actually just a presentation of facts and thoughts to explain where I am in all this. There are two main questions: 1) Are the incident waves from a very distant source, say a star very far away, interfering with one another to create one or more resulting...
  33. D

    Evidencing interference pattern using Young's slits and sunlight - help required

    I am an artist with some knowledge of physics and I am trying to build a pinhole camera to expose photographic film using sunlight that passes through a filter, pinholes and Young's slits. I would like to photograph an interference pattern using the sun as the subject. My prototype camera...
  34. M

    Interference Maxima and Newton's Rings (Please help with trig)

    Homework Statement A lens with radius of curvature R sits on a flat glass plate and is illuminated from above by light with wavelength λ (see picture below). Circular interference patterns, Newton's Rings, are seen when viewed from above. They are associated with variable thickness d of the...
  35. M

    Which describes the interference at P? (Multiple Choice)

    Homework Statement In Young’s double-slit interference experiment, if the rays that reach point P on the viewing screen have a path length difference of 2.50 wavelengths, which describes the interference at P? A. It is the central bright fringe. B. It is the first dark fringe to either...
  36. S

    Wavelength used in interference

    Homework Statement Two flat glass plates are stacked and a thin paper strip is inserted between them at one side, creating a narrow wedge-shaped space between the plates. As shown in the figure below, monochromatic light that has a wavelength in air is directed at the plates from above. When...
  37. D

    Phase difference in a two slit interference problem

    Homework Statement In the figure below, sources A and B emit long-range radio waves of wavelength λ = 390 m, with the phase of the emission from A ahead of that from source B by 90°. The distance rA from A to detector D is greater than the corresponding distance rB by 130 m. What is the phase...
  38. S

    Single particle single slit interference - question about the experiment

    Came across the below experiment, on Wikipedia, but don't understand how it was performed... It was shown experimentally that: in a double-slit system where only one slit was open at any time, interference was nonetheless observed provided the path difference was such that the detected...
  39. A

    How can we explain the behavior of interference patterns in different frames?

    A train is moving from the left to the right direction. There is a light source emitting 2 beams of lights toward 2 slits A and B at both ends of the train. The source is put near the slit A Than B. A ground observer is watching the scene and sees that the 2 light rays reaching A and B...
  40. P

    Antennas causing destructive interference

    Homework Statement Two radio antennas radiating in phase are located at points A and B, 200m apart. The radio waves have a frequency of 5.80MHz. A radio receiver is moved out from point B along a line perpendicular to the line connecting A and B. At what distances from B will there be...
  41. B

    Understanding Particle Self-Interference in the Double Slit Experiment

    I was wondering to what extent we understand the self interference of particles in the double slit experiment. More specifically, I have heard that a single particle, acting as a wave can pass through both slits at once and that is what causes the interference. This explanation seems a bit fishy...
  42. W

    Energy present in a localized area during nodal interference

    When two waves interact producing a "cancelling" effect as seen by noise reducing headsets, what kinematic energy is associate with the effected medium immediately near the cancellation point(standing wave)? Furthermore, in an ideal setting, would it be possible to instantly reorient the...
  43. A

    How Does Thin-Film Interference Create Color Effects?

    I consider myself very well-read on the phenomenon of thin-film interference: how it works, how it's used in lens making, etc. HOWEVER... there's one thing I don't get: Thin-film interference only occurs for one specific wavelength at any given point (according to all the sources I've read)...
  44. C

    Can waves of different types produce interference?

    Hi all. Just a quick question, probably a silly one. Due to wave-particle duality all particles have both wave-like and particle-like behaviors. The wave-like properties of, say, an electron can result in an electron interference pattern. So, my question is: Can waves of different things...
  45. K

    Constructive Interference Problem in the Time Domain

    Homework Statement Two waves on a string are given by the following functions: Y1 (x,t) = 4cos(20t-x) Y2 (x,t) = -4cos(20t+x) where x is in centimeters. The waves are said to interfere constructively when their superposition |Ys| = |Y1 + Y2| is a maximum and they interfere destructively when...
  46. L

    Very confused: why is the path difference in double slit interference dsinθ?

    Homework Statement The more I think about path difference, the more confused I get. First of all, HOW DO PEOPLE know that the path difference is dsinθ? Why do we draw a line coming from the first ray that is PERPENDICULAR to the second ray when determining path difference? Please see...
  47. K

    Double-Slit Interference Problem

    Homework Statement A physics instructor wants to produce a double-slit interference pattern large enough for her class to see. For the size of the room, she decides that the distance between successive bright fringes on the screen should be at least 2.81 cm. If the slits have a separation d...
  48. A

    Can Beats Be Heard When Tuning a Guitar Using the Beat Method?

    I'm studying wave interference and I have a few questions regarding it that I can't quite figure out: 1.) I was once taught that for waves to interfere, they have to be of the same frequency, but then how can beat interference occur? What are the actual requirements for interference? 2.)...
  49. C

    How can you prepare a state with a single photon?

    I'm trying to write up an experiment that I have done on single photon interference. The design is as follows: Class 2 HeNe laser 25 micron pinhole double slit output via CCD I have all the data, but I cannot find anything that says that having a small pinhole about 80cm from the double slit...
  50. P

    Explaining the Rainbow Colors in Thin Films: Interference Homework Problem

    Homework Statement When light is shined on thin films the interference pattern results in: a. there is no interference pattern *b. rainbow like colors c. light and dark pattern with no separation of colors d. a mirror quality reflection e. polarization of the light The...
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