ultraviolettiselta

Ultraviolettiselta, or ultraviolet radiation, refers to a portion of the electromagnetic spectrum with wavelengths shorter than visible light but longer than X-rays, typically ranging from 10 to 400 nanometers. It lies beyond the violet end of the visible spectrum, hence the name "ultraviolet." This type of radiation is invisible to the human eye but can be detected through specialized instruments or its effects on certain materials.

Ultraviolet radiation is naturally emitted by the sun and is divided into three main categories based on wavelength: UVA (315–400 nm), UVB (280–315 nm), and UVC (100–280 nm). UVA penetrates deeply into the skin, causing long-term damage such as premature aging and increasing the risk of skin cancer. UVB is primarily responsible for sunburn and plays a key role in the development of skin cancer, though it is also essential for the synthesis of vitamin D in the skin. UVC is highly energetic and is absorbed by the Earth's atmosphere, making it the least harmful to life on the surface but still useful in sterilization applications.

In addition to its effects on human health, ultraviolet radiation influences environmental processes, such as ozone depletion. The ozone layer absorbs most UVC and a significant portion of UVB, protecting life on Earth from excessive exposure. Artificial sources of ultraviolet radiation, such as mercury vapor lamps and LEDs, are used in applications like sterilization, fluorescence, and blacklight imaging.

While ultraviolet radiation has beneficial uses, excessive exposure can lead to skin cancer, cataracts, and weakened immune function. Protective measures, such as sunscreen, protective clothing, and avoiding peak sun hours, are recommended to minimize risks.