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11.S: Interference (Summary)

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    Key Terms

    coherent waveswaves are in phase or have a definite phase relationship
    fringesbright and dark patterns of interference
    incoherentwaves have random phase relationships
    interferometerinstrument that uses interference of waves to make measurements
    monochromaticlight composed of one wavelength only
    Newton’s ringscircular interference pattern created by interference between the light reflected off two surfaces as a result of a slight gap between them
    orderinteger m used in the equations for constructive and destructive interference for a double slit
    principal maximumbrightest interference fringes seen with multiple slits
    secondary maximumbright interference fringes of intensity lower than the principal maxima
    thin-film interferenceinterference between light reflected from different surfaces of a thin film

    Key Equations

    Constructive interference\(\Delta l = m\lambda\), for m = 0, ±1, ±2, ±3…
    Destructive interference\(\Delta l = (m + \frac{1}{2})\lambda\), for m = 0, ±1, ±2, ±3…
    Path length difference for waves from two slits to a common point on a screen\(\Delta l = d \, sin \, \theta\)
    Constructive interference\(d \, sin \, \theta = m \lambda\), for m = 0, ±1, ±2, ±3…
    Destructive interference\(d \, sin \, \theta = (m + \frac{1}{2})\lambda\), for m = 0, ±1, ±2, ±3…
    Distance from central maximum to the m-th bright fringe\(y_m = \frac{m\lambda D}{d}\)
    Displacement measured by a Michelson interferometer\(\Delta d = m \frac{\lambda_0}{2}\)

    Summary

    3.1: Young's Double-Slit Interference

    • Samuel J. Ling (Truman State University), Jeff Sanny (Loyola Marymount University), and Bill Moebs with many contributing authors. This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0).

    This page titled 11.S: Interference (Summary) was last modified on Sat, 19 Aug 2023 01:18:18 GMT and is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by OpenStax via source content that was edited to the style and standards of the LibreTexts platform.