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.

View More On Wikipedia.org
Recent contents Top users
  1. F

    Destructive interference and Conservation of energy

    I've been thinking a lot about conservation of energy recently, and in addition to my other thread, I have another (quite different) seeming "paradox" that I can't resolve. Suppose you have a laser shooting into a Michelson interferometer with distances such that the split beam exactly...
  2. C

    Electron Interference: Scanning Electron Microscope

    When a scanning electron microscope shoots electrons at the material they wish to observe , when the secondary electrons are ejected from the material and then received at the detector it seems like electron diffraction might affect the image , But it doesn't seem to , or maybe they got...
  3. GRB 080319B

    Can Refraction and Interference Both Cause Iridescent Effects?

    Is there a way to visually determine whether refraction or interference is the cause of the iridescent effect observed in rainbows, oil films/bubbles, insect shells/wings, cds/dvds, etc.? This question arose from when I was looking at thin films of minerals through a microscope. The slide was...
  4. G

    What happens if we use two lasers for interference?

    Consider the following: Two point-sources of lased light, one 600nm and the other 602nm. Each is collimated to form a beam 100 microns in diameter; thus, each forms a well-collimated laser beam. Aim each beam at each slit in a double-slit setup (each slit is 10 microns wide and 100 microns...
  5. jaketodd

    Interference Pattern Properties

    Why does the distance from a light source to the two slits make a difference in the interference pattern? Thanks, Jake
  6. S

    Interference - Frequency Interference -- Frequency

    Interference -- Frequency Homework Statement Two loudspeakers at an outdoor rock concert are located 3.5 meters apart. You are standing 16.1 meters from one of the speakers and 19 from the other. During a sound check, the technician sends the exact same frequency to both speakers while you...
  7. P

    Wave Generation from Point Sources: Interference Patterns and Radio Aerials

    Hi Everybody! I have been wondering about wave generation from point sources, and interference. I have noticed that if several point sources are sited in a line much more than one wavelength long, a very directional interference pattern develops. The closer the sources and the longer the line...
  8. K

    Question about interference by observation (double slit exp.)

    In the double slit experiment, under observation, the electron acts like a particle rather than a wave. From my understanding this is because the photon that hits it for observational purposes adds enough energy into the system to affect the electron and make it chose one single path rather than...
  9. R

    Can 3-D Interference Patterns Exist in Real Life?

    Is it possible to have a 3-D interference pattern ?? if yes how can i achieve it?
  10. R

    Interference pattern with some fringes missing

    hi i was wondering whether we can produce a interferece pattern with some bright fringes missing( i.e not appearing at all). If yes..how it can be achieved?:confused:
  11. J

    Destructive interference in a speaker value

    Homework Statement Speaker 1 is positioned at the origin and speaker 2 is at the position (0, 4.00) meters. They emit identical sound waves of wavelength 1.55 m, in phase. If you stand on the x-axis at (x, 0) meters, what is the smallest positive value for x for which you experience complete...
  12. N

    Interference in thin microscope films

    Homework Statement "One microscope slide is placed on top of another with their left edges in contact and a human hair under the right edge of the upper slide. As a result, a wedge of air exists between the slides. An interference pattern results when monochromatic light is incident on the...
  13. W

    Near ballistic light/photon interference

    Hi, For interference to take place, the light wave must retain their coherence. For scattering, when photon particles are scattered/dispersed/deflected, they should lose their phase relationship or coherence, should they be capable of interference? this may sound queer, i know interference...
  14. R

    Can sound wave also interference just like EM wave

    its my exam question.. i am not so sure... but i put it can't because sound is a wave of vibration which it can diffract but not interence... but i don't know.. can sound wave interference? cheers
  15. R

    Destructive Interference and the Conservation of Energy

    This is a question concerning the wave nature of light and the conservation of energy. Consider a prism that combines two sources of monochromatic, coherent (laser) light into one beam. The sources are adjusted so that the laser beams combine in phase resulting in constructive interference...
  16. M

    Slit interference pattern depends or whether there is a clock in the room?

    Below is a question (paraphrased) which I addressed to two physics lecturers on the subject of slit diffraction. The problem I have is that answer I received from them sounds so ridiculous and impossible that I find it difficult to accept. I asked the question independently to both lecturers...
  17. A

    Can Two Violins Play in Perfect Harmony? Exploring Wave Interference in Violins

    Why is it that when say 2 violins are playing the same tune at the same time, there is never any destructive interference and no sound is heard?
  18. P

    Interference fringes in Young's experiment

    Homework Statement Explain why wider slits at the same spacing could produce fringes at the outer edges brighter than some of the fringes nearer the centre. Homework Equations fringe spacing = (lamda x D) / slit separation width of central diffraction fringe = ( 2 x lamda x D ) /...
  19. A

    How Does Soap Film Thickness Affect Color in Thin-Film Interference?

    Homework Statement A soap film with different thicknesses at different placers has an unknown refractive index n and air on both sides. In reflected light it looks multicolored. One region looks yellow because destructive interference has removed blue ((\lambda_{vacuum}=469nm)) from the...
  20. T

    Interference with two speakers?

    Interference with two speakers??! Two speakers placed 1m apart emit sound of frequency f=1000Hz in phase. A listener walks along a line that is parallel to the line joining the two speakers and 8m from their midpoint. What is the distance he has to walk from the central maximum in loudness to...
  21. N

    Can Fourier Transform Be Applied to Discrete LDOS in Particle Interference?

    Hi In this paper, http://people.ccmr.cornell.edu/~jcdavis/publicationPDF/NaturePhys_3_865.pdf, page 2 figure 1c, there is a plot of the Fourier transformation of the local density of states for some energy E. There is a thing I don't quite understand: The LDOS is discrete, i.e. it depends on...
  22. T

    Thin film interference problem

    Hi, I'm a high school physics student and I'm having a lot of trouble with thin film interference Homework Statement A thin layer of oil (noil=1.25) is floating on water (n=1.33). How thick is the oil in the region that strongly reflects green light (λ=556nm)? Homework Equations noil/nwater...
  23. N

    Max Angle and Destructive Interference

    Homework Statement Determine the maximum angle θ for which the light rays incident on the end of the the optical fiber of radius 1 mm are subject to the total internal reflection along the walls of the fiber. Assume that the fiber has an index of refraction of 1.3 and that the outside medium...
  24. J

    Interference (Constructive and Destructive)

    Homework Statement You are standing in front of two side by side loudspeakers playing sounds of the same frequency. Initially you hear no sound. Then one of the speakers is moved away from you. The sound intensity increases until it reaches a maximum when the speakers are 0.75 m apart. As the...
  25. A

    Destructive Interference Question

    Light Question 1. Homework Statement A student enters Best Buy prepared to buy a pair of speakers. Before he does so, he conducts an experiment with them. He places the speakers 4.0 m apart and connects a signal generator to both speakers that produces a single and consistent tone...
  26. S

    Interference pattern formed by an air wedge.

    An air wedge is formed between two glass plates separated at one edge by a very fine wire. When the wedge is illuminated from above by a 600nm light and viewed from above, 30 dark fringes are observed. Calculate the radius of the wire. Am I correct to consider only the bottom surface of the top...
  27. O

    How to observe interference patterns with a simple experiment?

    Hello guys, I need desperate help. I am googling an simple experiment that can observe interference patterns ? can someone help me out please?
  28. C

    Exploring Interference Patterns in Air Wedges

    Homework Statement It's not a specific question. It's more of a general knowledge. As you know, an air wedge forms when two glass plates have one ends meeting each other and the other ends opening up. Here's the diagram...
  29. B

    Inductive interference from two EM coils (aka a transformer)

    I've been wondering about this for a long time. The little black box that you plug into the wall so you can power your electronic devices contains a general run-of-the-mill transformer. But if the power is completely shut off to the device: not draining any current waiting for a power button...
  30. A

    Thin-film interference question

    Homework Statement The table lists the range of wavelengths in vacuum corresponding to a given color. If one looks through a film which has a refractive index of 1.333 and thickness of 340 nm (nanometers), which color will be 100% transmitted through the film? Table (Color/Wavelength)...
  31. S

    Destructive Interference when walking toward an antenna

    Homework Statement Two antennas located at points A and B are broadcasting radio waves of frequency 96.0 MHz, perfectly in phase with each other. The two antennas are separated by a distance d=12.40m. An observer, P, is located on the x axis, a distance x=55.0m from antenna A, so that APB...
  32. A

    Destructive interference of light

    White light is shined perpendicularly onto a film of unknown thickness, with index of refraction n = 1.5. A. How thick would the film have to be for each of the following colors of light to be absorbed due to destructive interference? (15 points) Red (f = 4 * (10^14) Hz) Green...
  33. V

    Alternative Explanation for Double Slit Interference

    i think I have an alternative explanation to the double slit.We can assume that the slit surface is not completely smooth,thus a photon may enter these gaps thus allowing for interference in the case of single photon emitter
  34. G

    Interference of light - flat glass and an air wedge

    Homework Statement A fine hair separates one end of two pieces of flat glass to form and air wedge.when light of wavelength 670 nm is incident normally, 25 dark bands are observed (with one at each end).How thick is the hair? Homework Equations destructive interference: 2nt =...
  35. G

    Wave Interference and sound waves

    Homework Statement Two loudspeakers emit sound waves along the x-axis. A listener in front of both speakers hears a maximum sound intensity when speaker 2 is at the origin and speaker 1 is at x= 0.540 m. If speaker 1 is slowly moved forward, the sound intensity decreases and then...
  36. K

    Is the Calculation of a Radar Antenna's Height at 349 Meters Accurate?

    Q. A radar antenna is located atop a high cliff on the edge of a lake operates at a wavelength of 400m. A parallel beam of electromagnetic wave is received by the antenna at E. One ray directly comes to E and other along the path ABE (after reflection at the water surface) the first minimum is...
  37. J

    Interference due to a thin film

    Homework Statement A thin film with a refractive index of n=1.50 is surrounded by air. Wavelengths of light 360, 450, and 602 nm are the only visible wavelengths missing from the reflected light. What is the thickness of the film. Homework Equations The Attempt at a Solution One...
  38. U

    Waves travelling through mediums, destructive interference.

    Homework Statement light travels through air, hits a film (n=1.3) and underneath that film is glass (n=1.5). What thickness of film would result in destructive interference The lights wavelength is 500nm. Homework Equations n = c/v V = F*λ The Attempt at a Solution I...
  39. B

    Two Slit Interference Question

    Hey guys, I am trying desperately to figure this problem out. I have not done a problem like this ever before, and it is on our homework in a regular high school physics class. The teachers did not even teach us, this is just my attempt from research and previous knowledge. Homework...
  40. N

    Particle Interference: How QP Wavepacket Creates Standing Waves

    Hi guys Today my lecturer talked a little about quasiparticle interference (QPI). He said that if we place a QP on a metal containing a single impurity, then the QP wavepacket will travel outwards, and when it hits the impurity, it will get reflected back and create standing waves. I don't...
  41. D

    Measuring Interference Experimentally

    Hi everyone, I'm currently working on a project, a part of which involves building a sagnac interferometer. My group understands the theory behind its operation, and we are now in the process of collecting materials needed to build it. We are, however, unsure of a way to quantitatively...
  42. N

    How Do Radio Frequency Sources Create Interference Patterns?

    Homework Statement Two radio frequency sources broadcast waves of the same frequency. They are placed 1.0 m apart. Let the x-axis be the line from one source to the other, and let x = 0 be at one of the sources. Nodes are observed at x = 0.24 m, x = 0.49 m, x = 0.74 m. 1) What is the...
  43. A

    RSSI (Received Signal Strength Indication) and Interference

    Hi, I Want to know: High GSM RSSI mean Interference? the reason behind High RSSI ist only Interference? Thanks
  44. A

    Interference of Two Sound Waves: Phase Difference & Intensity

    Consider two loudspeakers (emitting sound waves of the same amplitude and wavelength of 15m) and an observer located in the x−y plane, with the two loudspeakers being at (2m, 0) and (−2m, 0), respectively, and the observer being at (0, 3m) initially. (i) Suppose the intensity of the combined...
  45. S

    Young's Slit Interference (Double Slit)

    Find the slit separation of a double slit arrangement that will produce interference fringes 11.5 mrad apart on a distant screen with light of wavelength 471.0 nm. tan(theta) = y/D asin(theta) = p * wavelength I know that I'm trying to solve for a, and that asin(theta) = 11.5, but I feel like...
  46. K

    Is 2t a Rough Estimate of Wavelength in Thin Film Interference?

    Hi guys, i have problem with Interference in Thin Films, i tried worked the solution not sure it is correct. Hope someone can help me check? Also there is some part on the topic i don't quite follow, 2t is the extra distance traveled inside the film, then is 2t is also rough estimate of...
  47. X

    Width of the first dark fringe (2 slit interference)

    Homework Statement In a double-slit experiment, the two narrow slits are spaced 0.20 mm apart. A viewing screen is put 1.2 m behind the slits. A parallel light ray is shining on the slits. (a) If the wavelength of the incoming light ray is 633 nm. What is the width of the central bright...
  48. D

    RI interference on a garage door

    I'm not an engineer and I figured an EE would be able to help me on this problem. I have a garage door opener that has lost its range due to RI. I've tried everything from powering down my entire house, replacing the mother board, and the remotes and nothing works. I've worked with the...
  49. E

    How Do Radiowaves Interfere Destructively at a Cliffside Radiotelescope?

    Homework Statement A radiotelescope is positioned at a height of h=150m on a cliff overlooking the sea. A very distant galaxy emitting radiowaves, wavelength 3m, is at an angle \theta above the horizion. The radiowaves reach the telescope both directly and after reflection off the water...
  50. W

    Interference of Waves from Two Sources and Beats

    Homework Statement Two loudspeakers emit 300 Hz notes. One speaker sits on the ground. The other speaker is in the back of a pickup truck. You hear eight beats per second as the truck drives away from you. What is the truck's speed? (Assume that the speed of sound is 343 m/s.) Homework...
Back
Top