avelengths can be
             divided into UVA (wavelength 320 to 400 nanometres), UVB (wavelength 280
             to 320 nanometres) and UVC radiation (100 to 280 nanometres).
             UVA (wavelength 320 to 400 nanometres, sometimes known as "black light" or
             "longwave" radiation) carries less energy than UVB and UVC, although UVA
             penetrates more deeply into the skin and underlying tissues. UVA is about
             1,000 times more effective than UVB in producing an immediate tanning effect,
             by causing the melanin in the epidermis to darken immediately (i.e. as soon as
             the skin is exposed). Intense, prolonged exposure to UVA can burn sensitive
             skin. Prolonged UVA exposure can damage underlying structures in the co-rium
             and causes premature aging of the skin.
             UVB (wavelength 280 to 320 nanometres, sometimes called "shortwave"
             radiation) carries much more energy than the longer waved UVA radiation,
             although it does not penetrate as deeply int
             ...