The term "ultraviolet light" is spelled using the IPA phonetic transcription as ʌltrəˈvaɪələt laɪt. The word "ultraviolet" comes from the Latin words ultra, meaning "beyond," and violet, which refers to a color in the visible light spectrum. The combination of these two words indicates the position of the ultraviolet light beyond the visible violet color. Ultraviolet light has shorter wavelengths than visible light, making it invisible to the human eye, but it has numerous uses in science and technology.
Ultraviolet light is a type of electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays. It is typically not visible to the human eye, although some people may perceive a faint violet glow in very high intensity ultraviolet radiation.
Ultraviolet light is divided into three categories based on wavelength: UVA, UVB, and UVC. UVA is the longest wavelength among the three and is the least energetic. It is the most commonly encountered ultraviolet light, with a range of 315-400 nanometers (nm). UVB has a shorter wavelength, ranging from 280-315 nm, and is more energetic than UVA. UVC is the most dangerous type of ultraviolet light, with the shortest wavelength between 100-280 nm, and is fortunately mostly absorbed by the Earth's atmosphere and doesn't reach the surface.
Ultraviolet light is produced by various sources, including the sun, blacklights, and special lamps used in scientific and industrial applications. It can have both beneficial and harmful effects. On one hand, it plays a crucial role in the production of vitamin D in the skin and has sterilizing properties, making it useful for disinfection purposes. On the other hand, excessive exposure to ultraviolet light can cause various health problems, such as sunburn, premature skin aging, eye damage, and an increased risk of skin cancer. Therefore, taking appropriate precautions, such as using sunscreen, wearing protective clothing, and avoiding prolonged exposure during peak hours, is important when dealing with ultraviolet light.
The word "ultraviolet" is derived from two Latin words: "ultra", meaning beyond or exceeding, and "violet", referring to the color in the visible light spectrum. "Ultraviolet" was coined by German physicist Johann Wilhelm Ritter in 1801 to describe the invisible electromagnetic radiation from the sun that lies beyond the violet end of the visible spectrum. Thus, "ultraviolet light" refers to the type of electromagnetic radiation that has a wavelength shorter than violet light, but longer than X-rays.