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Spectroscopy can detect a much wider region of the EM spectrum than the visible wavelength range of 400 nm to 700 nm in a vacuum. A common laboratory spectroscope can detect wavelengths from 2 nm to 2500 nm. [1] Detailed information about the physical properties of objects, gases, or even stars can be obtained from this type of device.
300 nm – greatest particle size that can fit through a HEPA (high efficiency particulate air) filter (N100 removes up to 99.97% at 300 nm, N95 removes up to 95% at 300 nm) [85] 300–400 nm – near ultraviolet wavelength; 400–420 nm – wavelength of violet light (see Color and Visible spectrum) 420–440 nm – wavelength of indigo light
The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling), is a unit of length in the International System of Units (SI), equal to one billionth (short scale) or one thousand million (long scale) of a meter (0.000000001 m) and to 1000 picometres.
Portrait of Anders Ångström [15]. In 1868, Swedish physicist Anders Jonas Ångström created a chart of the spectrum of sunlight, in which he expressed the wavelengths of electromagnetic radiation in the electromagnetic spectrum in multiples of one ten-millionth of a millimetre (or 10 −7 mm.) [16] [17] Ångström's chart and table of wavelengths in the solar spectrum became widely used in ...
Natural sources produce EM radiation across the spectrum. EM radiation with a wavelength between approximately 400 nm and 700 nm is directly detected by the human eye and perceived as visible light. Other wavelengths, especially nearby infrared (longer than 700 nm) and ultraviolet (shorter than 400 nm) are also sometimes referred to as light.
In the near-infrared range liquid water has absorption bands around 1950 nm (5128 cm −1), 1450 nm (6896 cm −1), 1200 nm (8333 cm −1) and 970 nm, (10300 cm −1). [ 19 ] [ 20 ] [ 15 ] The regions between these bands can be used in near-infrared spectroscopy to measure the spectra of aqueous solutions, with the advantage that glass is ...
The wavelengths of sound frequencies audible to the human ear (20 Hz–20 kHz) are thus between approximately 17 m and 17 mm, respectively. Somewhat higher frequencies are used by bats so they can resolve targets smaller than 17 mm. Wavelengths in audible sound are much longer than those in visible light.
IR is generally understood to include wavelengths from around 750 nm (400 THz) to 1 mm (300 GHz). [1] [2] IR is commonly divided between longer-wavelength thermal IR, emitted from terrestrial sources, and shorter-wavelength IR or near-IR, part of the solar spectrum. [3]