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.
Near-periodic waves over shallow water
Wavelength of a periodic but non-sinusoidal waveform.
A propagating wave packet
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.
Relationship between wavelength, angular wavelength, and other wave properties.

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

- 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.

39 related topics with Alpha

Overall
Simple ray diagram showing typical chief and marginal rays

Numerical aperture

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[[Image:Numerical aperture.svg|thumb|The numerical aperture with respect to a point

[[Image:Numerical aperture.svg|thumb|The numerical aperture with respect to a point

Simple ray diagram showing typical chief and marginal rays
Numerical aperture of a thin lens

is the wavelength of the light.

The 100-inch (2.54 m) Hooker reflecting telescope at Mount Wilson Observatory near Los Angeles, USA, used by Edwin Hubble to measure galaxy redshifts and discover the general expansion of the universe.

Telescope

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Optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation.

Optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation.

The 100-inch (2.54 m) Hooker reflecting telescope at Mount Wilson Observatory near Los Angeles, USA, used by Edwin Hubble to measure galaxy redshifts and discover the general expansion of the universe.
17th century telescope
The 60-inch Hale (debuted in 1908) considered to be the first modern large research reflecting telescope.
The primary mirror assembly of James Webb Space Telescope under construction. This is a segmented mirror and its coated with Gold to reflect (orange-red) visible light, through near-infrared to the mid-infrared
Modern telescopes typically use CCDs instead of film for recording images. This is the sensor array in the Kepler spacecraft.
A 1.2-meter (47 in) reflecting telescope
Binoculars
The Very Large Array at Socorro, New Mexico, United States.
Einstein Observatory was a space-based focusing optical X-ray telescope from 1978.
The Compton Gamma Ray Observatory is released into orbit by the Space Shutte in 1991, and it would operate until the year 2000
The reflectors of HEGRA detect flashes of light in the atmosphere, thus detecting high energy particles
Equatorial-mounted Keplerian telescope
A diagram of the electromagnetic spectrum with the Earth's atmospheric transmittance (or opacity) and the types of telescopes used to image parts of the spectrum.
Six views of the Crab nebula supernova remnant, viewed at different wavelengths of light by various telescopes
The Five-hundred-meter Aperture Spherical radio Telescope in Guizhou, China, is the world's largest filled-aperture radio telescope

The dishes are sometimes constructed of a conductive wire mesh whose openings are smaller than the wavelength being observed.

Interference pattern of double slits, where the slit width is one third the wavelength.

Extraordinary optical transmission

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Interference pattern of double slits, where the slit width is one third the wavelength.

Extraordinary optical transmission (EOT) is the phenomenon of greatly enhanced transmission of light through a subwavelength aperture in an otherwise opaque metallic film which has been patterned with a regularly repeating periodic structure.

Rayleigh scattering causes the blue color of the daytime sky and the reddening of the Sun at sunset.

Rayleigh scattering

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Rayleigh scattering causes the blue color of the daytime sky and the reddening of the Sun at sunset.
Rayleigh scattering causes clouds to appear colored. In this picture, it is due to the Tyndall effect that scatter the light on smoke particles during the 2021 Mexico forest fire season.
Figure showing the greater proportion of blue light scattered by the atmosphere relative to red light.
Scattered blue light is polarized. The picture on the right is shot through a polarizing filter: the polarizer transmits light that is linearly polarized in a specific direction.
Rayleigh scattering in opalescent glass: it appears blue from the side, but orange light shines through.

Rayleigh scattering, named after the 19th-century British physicist Lord Rayleigh (John William Strutt), is the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation.

The 64-meter radio telescope at Parkes Observatory as seen in 1969, when it was used to receive live televised video from Apollo 11

Radio telescope

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Specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky.

Specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky.

The 64-meter radio telescope at Parkes Observatory as seen in 1969, when it was used to receive live televised video from Apollo 11
Antenna of UTR-2 low frequency radio telescope, Kharkiv region, Ukraine. Consists of an array of 2040 cage dipole elements.
Ooty radio telescope, a 326.5 MHz dipole array in Ooty, India
Plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation.
The Very Large Array in Socorro, New Mexico, an interferometric array formed of 27 parabolic dish telescopes.
Atacama Large Millimeter Array in the Atacama desert consisting of 66 12-metre (39 ft), and 7-metre (23 ft) diameter radio telescopes designed to work at sub-millimeter wavelengths
alt=Five hundred meter Aperture Spherical Telescope under construction|The 500 meter Five hundred meter Aperture Spherical Telescope (FAST), under construction, China (2016)
alt=Green Bank Telescope|The 100 meter Green Bank Telescope, Green Bank, West Virginia, US, the largest fully steerable radio telescope dish (2002)
alt=Effelsberg 100-m Radio Telescope|The 100 meter Effelsberg, in Bad Münstereifel, Germany (1971)
alt=Lovell Telescope|The 76 meter Lovell, Jodrell Bank Observatory, England (1957)
alt=DSS 14 "Mars" antenna at Goldstone Deep Space Communications Complex|The 70 meter DSS 14 "Mars" antenna at Goldstone Deep Space Communications Complex, Mojave Desert, California, US (1958)
alt=Yevpatoria RT-70 radio telescope|The 70 meter Yevpatoria RT-70, Crimea, first of three RT-70 in the former Soviet Union, (1978)
The 70 meter Galenki RT-70, Galenki, Russia, second of three RT-70 in the former Soviet Union, (1984)

The angular resolution of a dish antenna is determined by the ratio of the diameter of the dish to the wavelength of the radio waves being observed.

Seal of the International Bureau of Weights and Measures (BIPM) – Use measure (Greek: ΜΕΤΡΩ ΧΡΩ)

Metre

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Base unit of length in the International System of Units (SI).

Base unit of length in the International System of Units (SI).

Seal of the International Bureau of Weights and Measures (BIPM) – Use measure (Greek: ΜΕΤΡΩ ΧΡΩ)
Meridian room of the Paris Observatory (or Cassini room): the Paris meridian is drawn on the ground.
Paris Panthéon
Triangulation near New York City, 1817.
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Creating the metre-alloy in 1874 at the Conservatoire des Arts et Métiers. Present Henri Tresca, George Matthey, Saint-Claire Deville and Debray
Closeup of National Prototype Metre Bar No. 27, made in 1889 by the International Bureau of Weights and Measures (BIPM) and given to the United States, which served as the standard for defining all units of length in the US from 1893 to 1960
Gravimeter with variant of Repsold-Bessel pendulum
Artist's impression of a GPS-IIR satellite in orbit.

In 1893, the standard metre was first measured with an interferometer by Albert A. Michelson, the inventor of the device and an advocate of using some particular wavelength of light as a standard of length.

Zero-mode waveguide

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A zero-mode waveguide is an optical waveguide that guides light energy into a volume that is small in all dimensions compared to the wavelength of the light.

Canonical commutation rule for position q and momentum p variables of a particle, 1927. pq − qp = h/2πi. Uncertainty principle of Heisenberg, 1927.

Uncertainty principle

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Any of a variety of mathematical inequalities asserting a fundamental limit to the accuracy with which the values for certain pairs of physical quantities of a particle, such as position, x, and momentum, p, can be predicted from initial conditions.

Any of a variety of mathematical inequalities asserting a fundamental limit to the accuracy with which the values for certain pairs of physical quantities of a particle, such as position, x, and momentum, p, can be predicted from initial conditions.

Canonical commutation rule for position q and momentum p variables of a particle, 1927. pq − qp = h/2πi. Uncertainty principle of Heisenberg, 1927.
The superposition of several plane waves to form a wave packet. This wave packet becomes increasingly localized with the addition of many waves. The Fourier transform is a mathematical operation that separates a wave packet into its individual plane waves. The waves shown here are real for illustrative purposes only, whereas in quantum mechanics the wave function is generally complex.
Position space probability density of an initially Gaussian state moving at minimally uncertain, constant momentum in free space
Werner Heisenberg and Niels Bohr
Heisenberg's gamma-ray microscope for locating an electron (shown in blue). The incoming gamma ray (shown in green) is scattered by the electron up into the microscope's aperture angle θ. The scattered gamma-ray is shown in red. Classical optics shows that the electron position can be resolved only up to an uncertainty Δx that depends on θ and the wavelength λ of the incoming light.

Problem 1 – If the photon has a short wavelength, and therefore, a large momentum, the position can be measured accurately. But the photon scatters in a random direction, transferring a large and uncertain amount of momentum to the electron. If the photon has a long wavelength and low momentum, the collision does not disturb the electron's momentum very much, but the scattering will reveal its position only vaguely.

Dots in the sky due to spatial aliasing caused by halftone resized to a lower resolution

Aliasing

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Effect that causes different signals to become indistinguishable when sampled.

Effect that causes different signals to become indistinguishable when sampled.

Dots in the sky due to spatial aliasing caused by halftone resized to a lower resolution
Illustration of 4 waveforms reconstructed from samples taken at six different rates. Two of the waveforms are sufficiently sampled to avoid aliasing at all six rates. The other two illustrate increasing distortion (aliasing) at the lower rates.

Waves must be sampled more densely than two points per wavelength, or the wave arrival direction becomes ambiguous.