Click here to see the latest start time for this test. The TSI Assessment is a college readiness test delivered through the Accuplacer system, specifically designed by the College Board to meet the requirements set forth by the Texas Legislature and the Texas Higher Education Coordinating Board (THECB).
7.2 The spectrum of the sun Visible light and infrared radiation constitute the major fraction of solar radiation reaching the atmosphere of the Earth (Fig. 7-1). Approximately 40 % of the radiation energy is visible light of wavelengths between 400 and 700 nm.. Visible Light and UV Radiation 75 Effects of the ozone layer Ozone, O 3, is produced when oxygen, O 2, in the upper atmosphere absorbs UVC (Î»). This absorption completely eliminates UVC from the solar radiation and dissociates oxygen molecules to oxygen atoms.
Thus, the atmosphere blocks about 77% of the Sun's UV, almost entirely in the shorter UV wavelengths, when the Sun is highest in the sky (zenith). Of the ultraviolet radiation that reaches the Earth's surface, more than 95% is the longer wavelengths of UVA, with the small remainder UVB.