Near-infrared, from 120 to 400 THz (2,500 to 750 nm) – Physical processes that are relevant for this range are similar to those for visible light. The highest frequences in this region can be detected directly by some types of photographic film, and by many types of solid state image sensors for infrared photography and videography. optical window. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/optical%20window. License: CC BY-SA: Attribution-ShareAlike OpenStax College, College Physics. December 17, 2012. Provided by: OpenStax CNX. Located at: http://cnx.org/content/m42444/latest/?collection=col11406/1.7. License: CC BY: Attribution The microwave portion of the electromagnetic spectrum can be subdivided into three ranges listed below from high to low frequencies: extremely high frequency (30 to 300 GHz), super high frequency (3 to 30 GHz), and ultra-high frequency (300 MHz to 3 GHz).

Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, that is, in the range 10 nm to 400 nm, corresponding to photon energies from 3 eV to 124 eV (1 eV = 1.6e -19 J; EM radiation with frequencies higher than those of visible light are often expressed in terms of energy rather than frequency). It is so-named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet. These frequencies are invisible to humans, but visible to a number of insects and birds. Energy is propagated through space in the form of electromagnetic (EM) waves, which are composed of oscillating electric and magnetic fields. EM waves do not require a substance (like air or water) to travel through, meaning that — unlike sound — they can travel through empty space. In a vacuum, all EM waves travel at the same speed: the speed of light (which is itself an EM wave). Like all waves, an EM wave is characterised by its wavelength, and the range of wavelengths we observe, from very long to very short, is what we refer to as the EM spectrum. We divide up the EM spectrum roughly according to how the waves behave when they interact with matter and each division has a name. So we have: radio waves, which have the longest wavelengths; microwaves; infrared; visible light; ultraviolet; x-rays; and finally gamma rays, which have the shortest wavelengths. Celestial objects such as stars, planets and galaxies all emit EM waves at various wavelengths and so different telescopes are designed to be sensitive to different parts of the EM spectrum. EM radiation in and around the visible part of the spectrum is often referred to broadly as ‘light’, with shorter wavelengths referred to as ‘bluer’ and longer wavelengths referred to as ‘redder’. Gamma rays. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Gamma_rays. License: CC BY-SA: Attribution-ShareAlike AM radio waves are used to carry commercial radio signals in the frequency range from 540 to 1600 kHz. The abbreviation AM stands for amplitude modulation—the method for placing information on these waves. AM waves have constant frequency, but a varying amplitude.

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Infrared light includes most of the thermal radiation emitted by objects near room temperature. Infrared light is emitted or absorbed by molecules when they change their rotational-vibrational movements. Colors that can be produced by visible light of a narrow band of wavelengths are called pure spectral colors. They can be delineated roughly in wavelength as: violet (380-450 nm), blue (450-495 nm), green (495-570 nm), yellow (570-590 nm), orange (590-620 nm), and red (620 to 750 nm). Visible wavelengths pass through the optical window, the Earth’s atmosphere allows this region of the electromagnetic spectrum to pass through largely unattenuated (see opacity plot in. FM radio waves are also used for commercial radio transmission, but in the frequency range of 88 to 108 MHz. FM stands for frequency modulation, another method of carrying information. In this case, a carrier wave having the basic frequency of the radio station (perhaps 105.1 MHz) is modulated in frequency by the audio signal, producing a wave of constant amplitude but varying frequency. terahertz radiation. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/terahertz_radiation. License: CC BY-SA: Attribution-ShareAlike

Boundless. Provided by: Boundless Learning. Located at: www.boundless.com//physics/definition/thermal-agitation. License: CC BY-SA: Attribution-ShareAlike Radio spectrum. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Radio_spectrum. License: CC BY-SA: Attribution-ShareAlike

spectral color: a color that is evoked by a single wavelength of light in the visible spectrum, or by a relatively narrow band of wavelengths. Every wavelength of light is perceived as a spectral color, in a continuous spectrum; the colors of sufficiently close wavelengths are indistinguishable. This figure shows the visible part of the spectrum, together with the colors associated with particular pure wavelengths. Red light has the lowest frequencies and longest wavelengths, while violet has the highest frequencies and shortest wavelengths. Solar UV radiation is commonly subdivided into three regions: UV-A (320–400 nm), UV-B (290–320 nm), and UV-C (220–290 nm), ranked from long to shorter wavelengths (from smaller to larger energies). By exploring this image, you can see how astronomers have used a set of single-colour images to construct the colour picture of a ring of star clusters surrounding the core of the galaxy NGC 1512. Each image represents a specific colour or wavelength region of the spectrum, from ultraviolet to near infrared, and shows the wide wavelength range covered by Hubble. Astronomers chose to study NGC 1512 in these colours to emphasise important details in the ring of young star clusters surrounding the core.

The optical window is also called the visible window because it overlaps the human visible response spectrum. This is not coincidental as humanity’s ancestors evolved vision that could make use of the most plentiful wavelengths of light.The near infrared (NIR) window lies just out of the human vision, as well as the Medium Wavelength IR (MWIR) window and the Long Wavelength or Far Infrared (LWIR or FIR) window though other animals may experience them. ozone layer. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/ozone_layer. License: CC BY-SA: Attribution-ShareAlike Visible light, as called the visible spectrum, is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is often simply referred to as “light”. A typical human eye will respond to wavelengths from about 390 to 750 nm (0.39 to 0.75 µm). In terms of frequency, this corresponds to a band in the vicinity of 400–790 THz. A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum. The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish. Unsaturated colors such as pink, or purple variations such as magenta, are absent, for example, because they can be made only by a mix of multiple wavelengths. Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency and therefore high energy. Gamma rays typically have frequencies above 10 exahertz (or >10 19 Hz), and therefore have energies above 100 keV and wavelengths less than 10 picometers (less than the diameter of an atom). However, this is not a hard and fast definition, but rather only a rule-of-thumb description for natural processes. Gamma rays from radioactive decay are defined as gamma rays no matter what their energy, so that there is no lower limit to gamma energy derived from radioactive decay. Gamma decay commonly produces energies of a few hundred keV, and almost always less than 10 MeV.Spectral color. Provided by: Wikipedia. Located at: en.Wikipedia.org/wiki/Spectral_color. License: CC BY-SA: Attribution-ShareAlike gamma ray. Provided by: Wiktionary. Located at: en.wiktionary.org/wiki/gamma_ray. License: CC BY-SA: Attribution-ShareAlike