[ 103 ] Earth and Space Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • The chart presents information on ultraviolet radiation. It is divided into wavelength ranges identified as UVA, UVB, and UVC. Radiation UVA UVB UVC Main human effect Aging Burning Wavelength 400 nm to 315 nm 315 nm to 280 nm 280 nm to 100 nm % reaching Earth 12 noon 95% 5% 0% % reaching Earth before 10 A.M. & after 2 P.M. 99% 1% 0% % reaching Earth (average) 97% 3% 0% NOTES creates vitamin D People are most likely to be at risk of sunburn at A. 10 A.M., because the UVA rays are the greatest. B. 12 P.M., because more UVB rays reach the earth. C. 2 P.M., because UVC rays are least harmful. D. 4 P.M., because the UVA rays have less strength.