A report on Wavelength

The wavelength of a sine wave, λ, can be measured between any two points with the same phase, such as between crests (on top), or troughs (on bottom), or corresponding zero crossings as shown.

Sinusoidal standing waves in a box that constrains the end points to be nodes will have an integer number of half wavelengths fitting in the box.

A standing wave (black) depicted as the sum of two propagating waves traveling in opposite directions (red and blue)

Wavelength is decreased in a medium with slower propagation.

$Refraction: upon entering a medium where its speed is lower, the wave changes direction.$

Separation of colors by a prism (click for animation)

Various local wavelengths on a crest-to-crest basis in an ocean wave approaching shore

A sinusoidal wave travelling in a nonuniform medium, with loss

A wave on a line of atoms can be interpreted according to a variety of wavelengths.

Wavelength of a periodic but non-sinusoidal waveform.

Pattern of light intensity on a screen for light passing through two slits. The labels on the right refer to the difference of the path lengths from the two slits, which are idealized here as point sources.

$Diffraction pattern of a double slit has a single-slit envelope.$

Spatial period of a periodic wave—the distance over which the wave's shape repeats.

- Wavelength

39 related topics with Alpha

$In a prism, dispersion causes different colors to refract at different angles, splitting white light into a rainbow of colors.$

Dispersion relation

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In the physical sciences and electrical engineering, dispersion relations describe the effect of dispersion on the properties of waves in a medium.

$In a prism, dispersion causes different colors to refract at different angles, splitting white light into a rainbow of colors.$

The free-space dispersion plot of kinetic energy versus momentum, for many objects of everyday life

Frequency dispersion of surface gravity waves on deep water. The red square moves with the phase velocity, and the green dots propagate with the group velocity. In this deep-water case, the phase velocity is twice the group velocity. The red square traverses the figure in the time it takes the green dot to traverse half.

Two-frequency beats of a non-dispersive transverse wave. Since the wave is non-dispersive, phase and group velocities are equal.

A dispersion relation relates the wavelength or wavenumber of a wave to its frequency.

A man standing next to large ocean waves at Porto Covo, Portugal

Wind wave

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Water surface wave that occurs on the free surface of bodies of water.

The phases of an ocean surface wave: 1. Wave Crest, where the water masses of the surface layer are moving horizontally in the same direction as the propagating wavefront. 2. Falling wave. 3. Trough, where the water masses of the surface layer are moving horizontally in the opposite direction of the wavefront direction. 4. Rising wave.

NOAA ship Delaware II in bad weather on Georges Bank

Surf on a rocky irregular bottom. Porto Covo, west coast of Portugal

Classification of the spectrum of ocean waves according to wave period

Stokes drift in shallow water waves ([[:File:Shallow water wave.gif|Animation]])

Stokes drift in a deeper water wave ([[:File:Deep water wave.gif|Animation]])

Photograph of the water particle orbits under a – progressive and periodic – surface gravity wave in a wave flume. The wave conditions are: mean water depth d = 2.50 ft, wave height H = 0.339 ft, wavelength λ = 6.42 ft, period T = 1.12 s.

The image shows the global distribution of wind speed and wave height as observed by NASA's TOPEX/Poseidon's dual-frequency radar altimeter from October 3 to October 12, 1992. Simultaneous observations of wind speed and wave height are helping scientists to predict ocean waves. Wind speed is determined by the strength of the radar signal after it has bounced off the ocean surface and returned to the satellite. A calm sea serves as a good reflector and returns a strong signal; a rough sea tends to scatter the signals and returns a weak pulse. Wave height is determined by the shape of the return radar pulse.
A calm sea with low waves returns a condensed pulse whereas a rough sea with high waves returns a stretched pulse. Comparing the two images above shows a high degree of correlation between wind speed and wave height. The strongest winds (33.6 mph) and highest waves are found in the Southern Ocean. The weakest winds — shown as areas of magenta and dark blue — are generally found in the tropical oceans.

Wave length (distance from crest to crest in the direction of propagation)

Top to bottom: Lights flashing at frequencies, 1 Hz and 2 Hz; that is, at 0.5, 1.0 and 2.0 flashes per second, respectively. The time between each flash – the period T – is given by 1⁄f (the reciprocal of f); that is, 2, 1 and 0.5 seconds, respectively.

Hertz

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Unit of frequency in the International System of Units (SI) and is defined as one cycle per second.

A heartbeat is an example of a non-sinusoidal periodic phenomenon that may be analyzed in terms of frequency. Two cycles are illustrated.

(For historical reasons, the frequencies of light and higher frequency electromagnetic radiation are more commonly specified in terms of their wavelengths or photon energies: for a more detailed treatment of this and the above frequency ranges, see electromagnetic spectrum.)

Propagation of de Broglie waves in 1d – real part of the complex amplitude is blue, imaginary part is green. The probability (shown as the color opacity) of finding the particle at a given point x is spread out like a waveform; there is no definite position of the particle. As the amplitude increases above zero the slope decreases, so the amplitude diminshes again, and vice versa. The result is an alternating amplitude: a wave. Top: plane wave. Bottom: wave packet.

Matter wave

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Example of wave–particle duality.

$Demonstration of a matter wave in diffraction of electrons$

The de Broglie wavelength is the wavelength,

The interference of two waves. When in phase, the two lower waves create constructive interference (left), resulting in a wave of greater amplitude. When 180° out of phase, they create destructive interference (right).

Wave interference

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Phenomenon in which two waves combine by adding their displacement together at every single point in space and time, to form a resultant wave of greater, lower, or the same amplitude.

Interference of right traveling (green) and left traveling (blue) waves in Two-dimensional space, resulting in final (red) wave

Interference of waves from two point sources.

A magnified image of a coloured interference pattern in a soap film. The "black holes" are areas of almost total destructive interference (antiphase).

Geometrical arrangement for two plane wave interference

Interference fringes in overlapping plane waves

Optical interference between two point sources that have different wavelengths and separations of sources.

Creation of interference fringes by an optical flat on a reflective surface. Light rays from a monochromatic source pass through the glass and reflect off both the bottom surface of the flat and the supporting surface. The tiny gap between the surfaces means the two reflected rays have different path lengths. In addition the ray reflected from the bottom plate undergoes a 180° phase reversal. As a result, at locations (a) where the path difference is an odd multiple of λ/2, the waves reinforce. At locations (b) where the path difference is an even multiple of λ/2 the waves cancel. Since the gap between the surfaces varies slightly in width at different points, a series of alternating bright and dark bands, interference fringes, are seen.

White light interference in a soap bubble. The iridescence is due to thin-film interference.

The Very Large Array, an interferometric array formed from many smaller telescopes, like many larger radio telescopes.

The fringe spacing increases with increase in wavelength, and with decreasing angle

Spectrum

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Condition that is not limited to a specific set of values but can vary, without gaps, across a continuum.

Diagram illustrating the electromagnetic spectrum

A Nolan chart of the political spectrum using (red leftism and blue rightism) coding

Soon the term referred to a plot of light intensity or power as a function of frequency or wavelength, also known as a spectral density plot.

$A diffraction pattern of a red laser beam projected onto a plate after passing through a small circular aperture in another plate$

Diffraction

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Obstacle or opening.

$A diffraction pattern of a red laser beam projected onto a plate after passing through a small circular aperture in another plate$

Infinitely many points (three shown) along length d project phase contributions from the wavefront, producing a continuously varying intensity θ on the registering plate.

$Thomas Young's sketch of two-slit diffraction for water waves, which he presented to the Royal Society in 1803.$

$Photograph of single-slit diffraction in a circular ripple tank$

$Circular waves generated by diffraction from the narrow entrance of a flooded coastal quarry$

$A solar glory on steam from hot springs. A glory is an optical phenomenon produced by light backscattered (a combination of diffraction, reflection and refraction) towards its source by a cloud of uniformly sized water droplets.$

$2D Single-slit diffraction with width changing animation$

$Numerical approximation of diffraction pattern from a slit of width four wavelengths with an incident plane wave. The main central beam, nulls, and phase reversals are apparent.$

$Graph and image of single-slit diffraction.$

$2-slit (top) and 5-slit diffraction of red laser light$

$Diffraction of a red laser using a diffraction grating.$

$A diffraction pattern of a 633 nm laser through a grid of 150 slits$

A computer-generated image of an Airy disk.

$Computer generated light diffraction pattern from a circular aperture of diameter 0.5 micrometre at a wavelength of 0.6 micrometre (red-light) at distances of 0.1 cm – 1 cm in steps of 0.1 cm. One can see the image moving from the Fresnel region into the Fraunhofer region where the Airy pattern is seen.$

The Airy disk around each of the stars from the 2.56 m telescope aperture can be seen in this lucky image of the binary star zeta Boötis.

$The upper half of this image shows a diffraction pattern of He-Ne laser beam on an elliptic aperture. The lower half is its 2D Fourier transform approximately reconstructing the shape of the aperture.$

$Following Bragg's law, each dot (or reflection) in this diffraction pattern forms from the constructive interference of X-rays passing through a crystal. The data can be used to determine the crystal's atomic structure.$

$Computer generated intensity pattern formed on a screen by diffraction from a square aperture.$

$Generation of an interference pattern from two-slit diffraction.$

$Computational model of an interference pattern from two-slit diffraction.$

$Optical diffraction pattern ( laser), (analogous to X-ray crystallography)$

$Colors seen in a spider web are partially due to diffraction, according to some analyses.<ref>{{cite web|url = http://www.itp.uni-hannover.de/%7Ezawischa/ITP/spiderweb.html|title = Optical effects on spider webs|author = Dietrich Zawischa|access-date = 2007-09-21}}</ref>$

$Diffraction on a sharp metallic edge$

$Diffraction on a soft aperture, with a gradient of conductivity over the image width$

The characteristic bending pattern is most pronounced when a wave from a coherent source (such as a laser) encounters a slit/aperture that is comparable in size to its wavelength, as shown in the inserted image.

Molecular vibration

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Periodic motion of the atoms of a molecule relative to each other, such that the center of mass of the molecule remains unchanged.

The molecule as an anharmonic oscillator vibrating at energy level E3. D0 is dissociation energy here, r0 bond length, U potential energy. Energy is expressed in wavenumbers. The hydrogen chloride molecule is attached to the coordinate system to show bond length changes on the curve.

The typical vibrational frequencies range from less than 1013 Hz to approximately 1014 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm−1 and wavelengths of approximately 30 to 3 µm.