Ultraviolet light, electromagnetic spectrum

The so-called peak power delivered by a pulsed laser is often far greater than that for a continuous one. Whereas many substances absorb radiation in the ultraviolet and infrared regions of the electromagnetic spectrum, relatively few substances are colored. Therefore, a laser that emits only visible light will not be as generally useful as one that emits in the ultraviolet or infrared ends of the spectrum. Further, witli a visible-band laser, colored substances absorb more or less energy depending on the color. Thus two identical polymer samples, one dyed red and one blue, would desorb and ionize with very different efficiencies. 

Absorption spectrum (Section 12.5) A plot of wavelength of incident light versus amount of light absorbed. Organic molecules show absorption spectra in both the infrared and the ultraviolet regions of the electromagnetic spectrum. 

C07-0007. A compact disc player uses light of frequency 3.85 X lO s to read the information on the disc, (a) What is this light s wavelength (b) In what portion of the electromagnetic spectrum (visible, ultraviolet, and so on) does this wavelength fall (c) What is the energy of one mole of photons at this frequency ... 

The use of ultraviolet (UV) spectroscopy for on-line analysis is a relatively recent development. Previously, on-line analysis in the UV-visible (UV-vis) region of the electromagnetic spectrum was limited to visible light applications such as color measurement, or chemical concentration measurements made with filter photometers. Three advances of the past two decades have propelled UV spectroscopy into the realm of on-line measurement and opened up a variety of new applications for both on-line UV and visible spectroscopy. These advances are high-quality UV-grade optical fiber, sensitive and affordable array detectors, and chemometrics. 

Nanometer Unit of length commonly used to define wavelength of light, particularly in the ultraviolet and visible ranges of the electromagnetic spectrum. It equals 10 m or 10 pm or 10 A. 

Ultraviolet Radiation The portion of the electromagnetic spectrum emitted by the sun adjacent to die violet end of die visible light range. Often called black light , it is invisible to the human eye but when it falls on certain surfaces it causes them to fluoresce or emit visible light responsible for the photo-oxidation of certain compounds including hydrocarbons. 

Calculate the energy difference between rotational levels j = 3 and j = 2. Find the wavelength of light corresponding to this energy gap. What region of the electromagnetic spectrum (infra-red, microwave, ultraviolet, etc.) does this correspond to ... 

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