Cod liver oil - a potentially toxic source of Vitamin A: Hypervitaminosis A can result from ingestion of too much vitamin A from diet, supplements, or prescription medications.
This visible light region consists of a spectrum of wavelengths that range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm. Expressed in more familiar units, the range of wavelengths extends from 7 x 10 -7 meter to 4 x 10 -7 meter.
Visible light spans from about 760 to 380 nanometers in wavelength, which is the same as about 430 terahertz to about 750 terahertz. The low-frequency end corresponds to light that we perceive as the color red. The high-frequency end is related to light that we see as violet.