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 is a small fraction of the entire electromagnetic spectrum with wavelengths ranging from 380 nm (nanometres or 10-9 m) to 740 nm. The whole bandwidth of the spectrum is illustrated in the following image. All the different types of electromagnetic radiation consist of photons of a specific wavelength. All objects that are warmer than their surrounding (that includes all the astronomical objects like stars, nebulae, planets, etc.) emit photons within a certain range of different wavelengths.