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. fluidistic

    A The different interference patterns in the double-slit experiment

    I've read on page 107 of the pdf http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=617AE275E5CECF5F0AFD69ACBC52141B?doi=10.1.1.205.6529&rep=rep1&type=pdf that . Thus it seems that there are three different interference patterns. 1: We do not try to detect the electron passing through the...
  2. Cc518

    What is the Maximum Wavelength for Constructive Interference of Sound Waves?

    Homework Statement Two in-phase loudspeakers, which emit sound in all directions, are sitting side by side. One of them is moved sideways by 3.0 m, then forward by 4.0 m. Afterward, constructive interference is observed 1/4 and 3/4 of the distance between the speakers along the line that joins...
  3. Y

    What is the Relation Between Distance and Angle in Double Slit Interference?

    Homework Statement question (iii) 2. Homework Equations D=sd/λ (where D is the distance from slit to screen, s is the distance to the central maxima, and d is the slit separation)[/B] The Attempt at a Solution I plugged the values s=0.3*10^(-3), d=4.5*10^(-3) and λ=633*10^(-9), and got the...
  4. Sandeep T S

    I Interference between an electron and a photon?

    Can we could interfere electron with photon, this question is come from logic both are waves. Is anyone did that before.?(I know that electron isn't a scalar wave)
  5. M

    B Have interference on single particles been mapped

    Interference (trying to measure) single "particles" in a double slit experiments causes them to discontinue wave like behaviour and perform as "particles". Has the consequence of a series of interference with single "particles" been mapped when they arrive at the detector, and does any such...
  6. W

    Intensity of Interference Pattern

    The Attempt at a Solution The solution I keep coming up with is (G) , but the solution sheet says it is (C). I assumed it was (G) because since the slit width is halved the central maximum is bigger so I assumed that X would now be part of the central maximum. Therefore the intensity would be I_0.
  7. Penguin98

    How Is Destructive Interference Achieved in a Liquid Film on Glass?

    Mentor note: Thread moved from Adv. Physics Homework 1. Homework Statement Light is incident normally from air onto a liquid film that is on a glass plate. The liquid film is 174 nm thick, and the liquid has index of refraction 1.60. The glass has index of refraction n = 1.50. Calculate the...
  8. G

    I No interference if orthogonally polarized

    Hi. A beam of previously unpolarized or diagonally polarized doesn't create an interference pattern behind a double slit if there is a vertically and horizontally oriented polarizer behind either slit. The classical explanation is that the electric field is a vector perpendicular to the...
  9. TechTree

    Electrical interference on data cables

    Hello, I've got two computers that are in separate rooms and I have placed plastic conduit through the small space above the ceiling. Which will have a USB data cable, an Ethernet network cable, and a HDMI cable inside. The conduit length is about 8m long. And I was wondering if this setup could...
  10. J

    I Detecting Interference Patterns with Large Objects: The Double Slit Experiment

    Why is it so difficult to detect interference patterns with larger objects in the double slit experiment(e.g. bacteria)?
  11. Aurora_b

    A problem about thin-film interference

    1. Problem Statement: A transparent film has thickness 0.00325 cm, refractive index= 1.4. Find a) order of interference at theta=0° and b) the first four angles at which red light 6500 A will form bright light fringes. Ans:[ a)-100 ; b) - 5.73°, 9.94°, 12.84°...
  12. A

    "Total" destructive interference of plane waves

    Hello. Let's suppose that we have a Michelson interferometer to study interference patterns of light. This time we use plane waves. If we set the whole thing up so that the two separated beams have a phase difference of π when they superpose, destructive interference ensues. Since we're...
  13. Beth N

    Thin-film interference: transmission & reflection of colors

    Homework Statement This is a 2 part question. I have a follow up question from the problem 1. A sheet of glass having an index of refraction of 1.40 is to be coated with a 187-nm thick film of material having a refractive index of 1.55 such that yellow light with a wavelength of 580nm (in...
  14. O

    I Measurement OF a Beamsplitter - Destroys Quantum Interference?

    In those experiments demonstrating quantum interference which rely on a beam splitter to create a superposition of a photon taking different paths, what would happen if one made a sufficient "measurement" of the momentum of the beamsplitter itself? Would or should it destroy the interference...
  15. P

    The Difference Between Diffraction And Interference Patterns

    I've recently come across this problem: Answer true or false. If light shines through 2 slits, will the diffraction pattern always be within the interference pattern. I don't understand this question, however. How can the interference and diffraction pattern be separated in this situation...
  16. YMMMA

    Path length differences/ interference problem

    Homework Statement In the figure below, Two wave sources, M and N, are vibrating in phase on the surface of water and generate waves of wavelength λ. Which of the following values for the distances MP and NP will result in minimum disturbance at a particular point P on the surface of the water...
  17. MatthijsRog

    What constitutes a closed end in acoustic resonance in tubes

    Dear all, For my students, I'm currently trying out some experiments they can do to simulate acoustic processes. One of the topics that we will be discussing is that of standing waves. Although I have never done it before--I come from a completely different background--I want to create...
  18. S

    Correct statement about coherent sources and interference

    Homework Statement Which of the following statements is correct? a. coherent sources are not needed to produce interference fringes b. two coherent light sources do not always produce bright and totally dark fringes on a screen c. the atoms in a tungsten filament lamp produce coherent light...
  19. A

    Misc. Interference Between Two Speakers -- Real Life Version of a HW problem

    Hello, Many of you are familiar with the homework problem that goes like the below, and though straightforward to solve in most general physics homework sets, I need to help getting it to work, which is not so easy in real-life. Consider two speakers separated by 2.0 meters. Find the points...
  20. ccdani

    Transmission of blue light through ceramics and surface roughness effects

    Hey :) I measured the transmission of blue visible light (350-550nm) through lithiumdisilicate ceramics with an ulbricht ball and an spectrometer. The light source was a led dental curing unit (bluephase style). The light guide was positioned direct on the ceramics. Now I wanted to test...
  21. Jeremy Feng

    Young's Modulus Experiment With a Glass Screen

    Homework Statement Homework Equations Path difference is nλ at maxima, (n+0.5)λ at minima The Attempt at a Solution I think the phase difference between S1 and S2 is not 0 anymore, because the wave effectively takes a longer distance by going through S2. Thus, there is no longer a central...
  22. Y

    Interference Fringes in a Diffraction envelope

    Homework Statement My question is at https://imgur.com/a/lDOUzjY . The de Broglie wavelength of the atoms in question is 45 pm. The distance from the slits to the detection plane is 1.95m. Each slit width is 1 micrometer. The distance between the slits is 8 micrometers. 2. Homework Equations...
  23. F

    What is the equation for constructive interference in thin film interference?

    Homework Statement Between two pieces of glass (##n_1=1.70##), there is a thin film of water (##n_2=1.33## and width ##d=1 \mu m##). If there is normal-incidence of white light on the water surface, find: (a) which wavelenghts can be seen in the light transmitted (answer: 667 nm,533 nm,444 nm...
  24. R

    Thin film interference problem

    Homework Statement You are working with the mineral fluorite (CaF2, n=1.43) and have a sample that is coated with a layer of liquid 158 nm thick. For various wavelengths of visible light incident normal to the surface of the liquid, you observe very strong reflection for green light (λ = 510...
  25. T

    Destructive interference for distance-specific illumination?

    From a practical standpoint, can we combine two (or more) lasers tuned to almost-but-not-quite identical frequencies to create distance-specific illumination? For instance, say we have a 1 micron laser and a 0.9999 micron laser which we combine through some beam-combiner optics. In theory I...
  26. Erickly

    Film Thickness for Minimum Reflection of Monochromatic Light: How to Calculate?

    Homework Statement Monochromatic light of wavelength, λ is traveling in air. The light then strikes a thin film having an index of refraction n1 that is coating a material having an index of refraction n2. If n2 is larger than n1, what minimum film thickness will result in minimum reflection of...
  27. F

    Double slits and convex lens interference

    Homework Statement Two slits (of width ##a=39 \mu m##) are lighted up with a monocromatic wave of ##\lambda=632,8 nm##. The distance between slits and the screen id ##D=4 m##. The distance between the slits id ##d=195 \mu m##. In front of the slits there are a convergent lens with focal length...
  28. malak

    I Michelson interferometer dimensions

    hi i want to design michelson interferometer device for measuring small distance movement i am using laser diode with a wavelength 635 nm and power 3 mw can anyone tell me how can i decide the dimensions (from source to beam splitter , for beam splitter to fixed mirror , from beam splitter to...
  29. P

    Why is there interference if EM waves don't interact?

    Radio waves pass through everywhere without interacting with each other and that enables us to hear different phone calls and radios without disturbance. However, we do hear some noise sometimes because different signals interfere with each other. How are both of the last two statements true (if...
  30. S

    Can you please check this (destructive interference).

    If it is wrong can you please pinpoint where i am going wrong. Thank you. 1. Homework Statement https://imgur.com/a/0STmmWt (uploaded picture because it has a diagram) Homework Equations To sense destructive interference , the person must be one half wavelength (0.5λ) closer or farther from...
  31. H

    New wave after superposition (interference)

    Homework Statement 1. Homework Statement [/B] The displacement y of standing wave that is obtained by a superposition of waves : Y1 = 3 sin (2##\pi##(0.5t - 0 25 x)) Y2 = 3 sin (2##\pi##(0.5t + 0 25 x))Homework Equations Formula for standing waves Y = 2Asinkx coswt The Attempt at a Solution Y1...
  32. C

    I Analysis of Ultrasonic Waves at a point

    I have a question regarding a theoretical analysis of Ultrasonic waves : The next picture represents a system of transducers sitting on fixed boards: Datum: * there are 4 transducers ( represented by blue color , indexed by letter ' T ' ) , each outputting Ultrasonic wave (represented by...
  33. R

    Sound Wave Interference: Investigating Null Results with Sound Level Meter Data

    I collected this data by moving a sound level meter slowly through a total length of 0,75 meter between two speakers pointing towards each other. The wavelength of the sine waves was 0,343 meters and the frequency was 1000 Hz. The sound level meter measured the sound in dbA 20 times a second...
  34. Clara Chung

    White light interference pattern and its resolution criteria

    Homework Statement Homework EquationsThe Attempt at a Solution I don't know how to do part d. For di, i know that separation of arm d should be small in order to have spatial coherence. For dii, what is the meaningful criterion, can I say the primary max of blue light lies on the first zero...
  35. prodo123

    Frequency at which no destructive interference occurs

    Homework Statement Two speakers A and B, 2.00 m apart, produce a sine wave at the same frequency and phase. A microphone is placed on the line BC perpendicular to AB, at a distance x from B. The speed of sound is v=344 m/s. For a frequency ƒ low enough, there will be no destructive...
  36. aatari

    Sound wave Interference from Two Speakers

    Hi guys I am having trouble determining a quite spot based on where you stand in respect to distance from the speakers. I have solved the question below but I need someone to explain to me how the "n" value can be used to determine a quite or not-quite spot. Am I looking for whole numbers? If n...
  37. M

    Inteference Fringes of Double Slit Experiment in Water

    Homework Statement Suppose a double-slit experiment is immersed in water (with an index of refraction of 1.33). When in the water, what happens to the interference fringes? Homework Equations λ = λ0 / n y = (λmL) / d d = distance between slits L = distance to viewing screen n = index of...
  38. S

    Double Slit Wave Interference - what is m?

    Hi, I'm doing a very simple problem, but I don't understand the diagram provided (see image below). What is m here? I know that m is the order with respect to the central bright fringe, but there isn't a central bright fringe (assuming those circles are the bright fringes)? Homework...
  39. Derek P

    Interference puzzle - Where does the energy go?

    A laser beam is split into two identical beams which impinge on a half-silvered surface from opposite sides. The reflected wave is out of phase with the transmitted wave. There is destructive interference on both outputs. Where does the energy go? See my avatar - I can't upload my own picture...
  40. Adiater

    I Double-Slit Interference w/ Separate Sources

    If you have two similar coherent sources which are separated from each other by a barrier. Now one source sends particles one by one into one slit and the other sends particles into the other in a double slit interference experiment. Now, the photons are always undistinguishable, so they should...
  41. Ajaroy

    How to calculate the path difference in this question

    1. Homework Statement Two speakers S1 and S2 derived by the same amplifier and placed at y=1 and y = - 1.The speakers vibrate in phase at 600 Hz. A man stands on the x-axis at a very large distance from the origin and starts moving parallel to the Y - axis. The speed of sound in air is 330ms-1...
  42. B

    Relationship between interference and arm length in MZI

    A question about the Mach-Zehnder interferometer. My understanding is: If its two arms are equally long, there is destructive interference in one output and constructive interference in the other output. So, the intensity of light detected at the first output should be 0% and at the second...
  43. brainbaby

    RF Tuner: Adjacent Channel Interference Rejection Filters

    Hi guys The IF section of both monochrome and colour receivers must include rejection filters to suppress adjacent channel interference... Why exactly so, since the work of rf tuner in television receiver is to select a particular channel and as the required channel is selected it then passes...
  44. Sheldon11

    B Interference pattern intensity

    why the intensity is the most in the center in interference pattern?
  45. A

    Intensity for Young’s Double Slit Interference

    Homework Statement Hi The experimental setup involved a helium neon laser of wavelength 670nm +- 1nm, pointed towards a lens with focal length 500mm +- 1mm. (so that the equations used corresponded to the far field diffraction pattern) and onto a photo diode so that for all intents and...
  46. F

    Predicting Changes in Interference Patterns using Laser Interference Equations

    Homework Statement Imagine that you are conducting an activity with a laser to create an interference pattern. Use the appropriate equations to predict two ways (other than the way described in the following example) to change the interference pattern in order to have closer fringes. Explain...
  47. F

    I Exploring Oscillations & Interference in Particle Physics

    I will soon start with the course introduction to QFT and are hence an amateur on the subject. However I could not help but wonder, If particles are describes by oschlliations in a field, how can a "bigger body" be made up of several such oscillation? (A bigger particle is made out of several...
  48. aatari

    Light wave Interference - Angler Fish Problem

    Hi Guys, I have attempted to solve the following question and was hoping someone can have a look and give some feedback. Any help will be greatly appreciated. Thanks! 1. Homework Statement Angler fish emit light through bioluminescence. An angler fish is swimming in a fish tank that has a...
  49. E

    Interference of Multiple Waves: How to Determine Phase for Maximum Intensity?

    Homework Statement Four identical wave sources (s1,s2, s3,s4 ) are located at the corners of a square. We know the phase at three sources: 0 at s1, π/4 at s2, π/2 at s3. Whet is the phase we have to give to s4 in order to have a maximun of intensity at the center of the square? Homework...
  50. C

    Can an axisymmetric electric field be created without charges?

    That is, a field that accelerates charges in opposite directions on each side of an axis. I was thinking about interference of similarly polarized waves traveling in opposite directions (so that electric field peaks and valleys overlap but magnetic field adds constructively) - would there be an...
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