Wavelength, solar energy

Dobson spectrophotometer spect A photoelectric spectrophotometer used in the determination of the ozone content of the atmosphere compares the solar energy at two wavelengths in the absorption band of ozone by permitting the radiation of each to fall alternately upon a photocell. dab-san Spek-tro-fa tam-ad-ar docosane org chem C22H46 A paraffin hydrocarbon, especially the normal isomer CH3(Cf2l2)2oCH3. dak-a,san ... 

Blackbody Radiation The process by which solar energy absorbed by the Earth is transformed into longer wavelengths and reradiated back into the atmosphere. In physics, a blackbody is a perfect adsorber of electromagnetic radiation that can be released at other wavelengths with no loss of total energy. 

Solar energy is defined as the radiant energy transmitted by the Sun and intercepted by Earth. It is transmitted through space to Earth by electromagnetic radiation with wavelengths ranging between 0.20 and 15 pm. The availability of solar fiux for terrestrial applications varies with season, time of day, location, and collecting surface orientation. In this section, we shall treat these matters analytically (Kutz, 2007). 

The sun s total radiation output is approximately equivalent to that of a blackbody at 10,350°R (5750 K). However, its maximum intensity occurs at a wavelength that corresponds to a temperature of 11,070°R (6150 K) as given hy Wien s displacement law. A figure plotting solar irradiance versus spectral distribution of solar energy is given in Fig. 9. See also Solar Energy. 

Utilization of data obtained from various plasma sources (e.g. beam-foil, tokamak and laser-produced plasma [287]) enabled the identification with high accuracy of the lines of highly ionized atoms in solar spectra. A special commision No 14 on Atomic and Molecular Data of the International Astronomical Union coordinates the activity on systematization of spectroscopic data, informs the astrophysics community on new developments and provides assessments and recommendations. It also provides reports which highlight these new developments and list all important recent literature references on atomic spectra and wavelength standards, energy level analyses, line classifications, compilations of laboratory data, databases and bibliographies. 

The main drawbacks to the use of solar energy are its rather low density (ca. 1 kW m-2 on i clear day with the sun directly overhead), its wide wavelength spread and its somewhat unpredict able nature caused by different weather patterns. Nevertheless, calculations have shown that it i in theory possible to provide the energy needs of the whole world provided that the energy cai... 

Figure 3. Plot showing the variation of solar energy conversion efficiency with threshold wavelengths at sea level. The solid vertical lines represent the energies required for decomposition of water using one or two photons per molecule of water respectively (4 photons would be at 2000 nm). The dashed vertical lines represent computed values for these threshold wavelengths taking into account unavoidable thermodynamic losses (adapted from ref. 8)...

Above the mesopause, Tg increases rapidly. In this region, termed the thermosphere (Fig. 2), absorption of short wavelength solar radiation is occurring (Fig. 3) which results in the efficient photodissociation of molecular oxygen, and the photoionization of the O atoms so produced and of the 02 and N2 molecules. Thus, Tg increases beyond 1000 K, approaching 2000 K at times. Whereas below 100 km the neutral gas particles, the ions and the electrons in the plasma all possess the same kinetic temperature, above 100 km, due to the lower pressure and the subsequent reduced electron/heavy particle collision frequency and the large amount of energy imparted to the photoelectrons, the electron temperature, Te increases above Tg (and Tj the ion temperature, which is Tg, see Fig. 2). 

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