A report on Wavelength and Electromagnetic spectrum

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 diagram of the electromagnetic spectrum, showing various properties across the range of frequencies and wavelengths

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

Plot of Earth's atmospheric opacity to various wavelengths of electromagnetic radiation. This is the surface-to-space opacity, the atmosphere is transparent to longwave radio transmissions within the troposphere but opaque to space due to the ionosphere.

Wavelength is decreased in a medium with slower propagation.

Plot of atmospheric opacity for terrestrial to terrestrial transmission showing the molecules responsible for some of the resonances

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

The amount of penetration of UV relative to altitude in Earth's ozone

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.

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

Relationship between wavelength, angular wavelength, and other wave properties.

The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.

- Electromagnetic spectrum

The name originated with the visible light spectrum but now can be applied to the entire electromagnetic spectrum as well as to a sound spectrum or vibration spectrum.

- Wavelength

7 related topics with Alpha

Light

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The electromagnetic spectrum, with the visible portion highlighted

Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily

$Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.$

Hong Kong illuminated by colourful artificial lighting.

$Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.$

Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).

Electromagnetic radiation

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In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, propagating through space, carrying electromagnetic radiant energy.

Shows the relative wavelengths of the electromagnetic waves of three different colours of light (blue, green, and red) with a distance scale in micrometers along the x-axis.

In electromagnetic radiation (such as microwaves from an antenna, shown here) the term "radiation" applies only to the parts of the electromagnetic field that radiate into infinite space and decrease in intensity by an inverse-square law of power, so that the total radiation energy that crosses through an imaginary spherical surface is the same, no matter how far away from the antenna the spherical surface is drawn. Electromagnetic radiation thus includes the far field part of the electromagnetic field around a transmitter. A part of the "near-field" close to the transmitter, forms part of the changing electromagnetic field, but does not count as electromagnetic radiation.

Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This 3D animation shows a plane linearly polarized wave propagating from left to right. The electric and magnetic fields in such a wave are in-phase with each other, reaching minima and maxima together.

Representation of the electric field vector of a wave of circularly polarized electromagnetic radiation.

Electromagnetic spectrum with visible light highlighted

Rough plot of Earth's atmospheric absorption and scattering (or opacity) of various wavelengths of electromagnetic radiation

All of these waves form part of the electromagnetic spectrum.

The position of an electromagnetic wave within the electromagnetic spectrum can be characterized by either its frequency of oscillation or its wavelength.

Visible spectrum

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Newton's color circle, from Opticks of 1704, showing the colors he associated with musical notes. The spectral colors from red to violet are divided by the notes of the musical scale, starting at D. The circle completes a full octave, from D to D. Newton's circle places red, at one end of the spectrum, next to violet, at the other. This reflects the fact that non-spectral purple colors are observed when red and violet light are mixed.

Newton's observation of prismatic colors (David Brewster 1855)

How visible light interacts with objects to make them colorful

Approximation of spectral colors on a display results in somewhat distorted chromaticity

Earth's atmosphere partially or totally blocks some wavelengths of electromagnetic radiation, but in visible light it is mostly transparent

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye.

Electromagnetic radiation in this range of wavelengths is called visible light or simply light.

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

As scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum.

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.

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.

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

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

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 word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors.

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

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.)

one nanometric carbon nanotube, photographed with scanning tunneling microscope

Nanometre

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Unit of length in the metric system, equal to one billionth (short scale) of a metre (0 m).

Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The nanometre is often used to express dimensions on an atomic scale and mostly in the molecular scale.

The nanometre is also commonly used to specify the wavelength of electromagnetic radiation near the visible part of the spectrum: visible light ranges from around 400 to 700 nm.