What is Light interference: Definition and 26 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. Daniel Petka

    I Can a single photon of a single frequency pass through a FP cavity?

    I was watching this amazing video about FP cavities and the creator mentioned that a single photon shouldn't pass through that cavity. Only multiple photons can. This doesn't make sense to me. The cavity works thanks to interference and single photons still interfere with themselves, so...
  2. L

    A Energy problem of light interference

    During equal thickness interference, adjust the inclination of the two plates to expand the spacing of interference fringes to 10mm. Then, if a light with a width of 5mm is used for equal thickness interference, whether an interference pattern will be observed, and the width of the interference...
  3. 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...
  4. rkatcosmos

    Using multiple mirrors in Michelson Interferometer

    The number of mirrors typically used in Michelson Interferometer is 2. I am looking up the respective Wikipedia article and MIT's youtube video. I am wondering, for the sake of one of my experiment, whether more than 2 mirrors can be used in the interferometer? I require the traversing mirror...
  5. P

    What happens to intensity during light interference?

    Dear Every Smart Person, I am not a scientist or a physicist by any means, but I have a concept that has been literally driving me crazy all day. No matter how much I read, I can't make sense of it. Here it goes. I work in the LED Lighting space. In that space, there are two types of LEDs: a...
  6. Hamal_Arietis

    Light Interference: Find Condition of d for Constructive Interference

    Homework Statement [/B] Find condition of d that constructive interference occurs with m=1,2,3,... a)##(m-\frac{1}{2})\frac{\lambda}{2}## b)##m\frac{\lambda}{2}## c)##(m-\frac{1}{2})\lambda## d)##m\lambda## Homework Equations optical path difference (OPD) must equal ##m\lambda## The Attempt at...
  7. kamhogo

    Single-sit vs. Double-slit vs. Diffraction grating

    Homework Statement Briefly state one characteristic of single-slit /double-slit/diffraction grating interference pattern that allow you to clearly distinguish one from the others. Homework Equations NoneThe Attempt at a Solution Single-slit: Taller, broader central maximum.Double-slit: More...
  8. vetgirl1990

    Interference of thin films

    Homework Statement (a) Calculate the minimum thickness of a soap bubble film that results in constructive interference in the reflected light if the film is illuminated with light whose wavelength in free space is λ=600nm. The index of refraction of the soap film is 1.33. (b) What is the film...
  9. Nickyvl

    Unexpected white light interference pattern

    Dear fellow Physicists, For my project I wanted to measure the thickness of a glass plate with white light interference. Before being able to measure, I had to setup an interferometer. Unlike with a Laser, with white light it is hard to find the interference pattern since the coherence length...
  10. J

    Interpreting Young's Light Interference Data: Can You Help Me Clear My Doubts?

    Hello! I have done this experiment and managed to find this data: http://puu.sh/bO8TJ/ac3520ec8b.png Am I right for saying that the position that reaches the value of 5 amps are the central bright and the position 220-ish as the 1st bright order and the position 260-ish as the 2nd bright...
  11. E

    Light Interference Wave Equation - Assumption

    Homework Statement Homework Equations In question. The Attempt at a Solution To be clear it's part (vi) that's unclear to me. In order to ignore the cosine term it has to reduce to 1. This can happen, only if k(x1+x2)/2 = ωt Is this a correct assumption ? Also, it is known that k = 2∏/λ...
  12. Q

    Calculating Wavelength from Interference Pattern: Narrow Slits and Laser Light

    Homework Statement Two narrow slits are cut into a sheet of paper and set in front of a laser beam, causing an interference pattern to appear on the wall. If the distance from one slit to the third bright fringe is 0.5000004 m and the distance from the other slit to the same bright fringe is...
  13. jaumzaum

    Where does interference occur in light waves?

    I'm really confused about the way the light can suffer interference. I'll try to explain the way I think all this occurs and the question I have if this explanation was correct. I would like you guys to correct me if anything I say is wrong and to try to explain me the final question. Light is...
  14. 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...
  15. 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...
  16. M

    Three problems concerning light interference and snells

    5. Two slits are separated by 0.195 mm. An interference pattern is formed on a screen 33.0 cm away by 656.3-nm light. Calculate the fraction of the maximum intensity a distance 0.600 cm away from the central maximum. d =.000195m L = .33 m lambda = 656.3 nm y = .006m it's a small angle...
  17. B

    Laser light interference on liquid metal. why?

    I wanted to make tiny movements of the Earth visible by reflecting laser light off liquid gallium metal. It did produce nice reflections on my wall, showing dramatic wobbles of very tiny movements of the liquid gallium. It did however produce light interference patterns which I cannot explain...
  18. I

    Thin film light interference question

    Homework Statement A uniform film of oil (n=1.31) is floating on water. When sunlight in air is incident normally on the film, an observer finds that the reflected light has a maximum at wavelength (lambda) = 450nm and a minimum at wavelength (lambda) = 600nm. What is the thickness of the...
  19. M

    Problem and thoughts about simple light interference

    1. With the later on given info, is it possible to through geometry calculate the wave length of a HeNe Laser? 2. Homework Equations and facts A Helium Neon laser emitts light through a double slit and towards a screen where a central image and the first dimmer bands can be seen. The...
  20. N

    Light Interference Webassign question

    Homework Statement Light of wavelength 525 nm is used to illuminate normally two glass plates 26 cm in length that touch at one end and are separated at the other end by a wire of radius 0.03 mm. How many bright fringes appear along the total length of the plates? Homework Equations...
  21. A

    Thin film red light green light interference

    Homework Statement A mixture of red light (wavelength vacuum = 652 nm) and green light (wavelength vacuum = 477 nm) shines perpendicularly on a soap film (n = 1.333) that has air on either side. What is the minimum nonzero thickness of the film, so that destructive interference removes the...
  22. W

    What is the key requirement for producing interference patterns with light?

    Homework Statement What characteristic of light is needed to produce interference patterns? ( like the grainly pattern of light demonstrated in lab) The Attempt at a Solution ok,, so i missed lab and did a makeup so I never saw what is being described. I am guessing that the grainy...
  23. S

    Light interference homework

    the question is A plane wave of 400-nm light is incident on a 25-µm slit in a screen, as shown in the figure below. At what incident angle will the first null of the diffraction pattern be on a line perpendicular to the screen?http://img130.imageshack.us/img130/9766/inter9ax.jpg I really do...
  24. B

    Why is there no visible light interference from two light sources?

    How come we don't see light interference from two light sources? ex. two candles
  25. M

    Light Interference: Slit Separation & Maxima Observation

    im a little stuck on part b of this question. Light of wavelength 633 nm from a helium-neon laser is shone normally on a plane containing two slits. The first interference maximum is 85 cm from the central maximum on a projection screen 14 m away. (a) Find the separation of the...
  26. G

    Light Interference: Why Don't We See 2 Sources? 2 Reasons

    Why don't we see interference of light from two light sources such as two candles? 2 reasons are required. Thanks