Ultraviolet light in the context of "Photoelectron"

Epicuticular wax is a waxy coating which covers the outer surface of the plant cuticle in land plants. It may form a whitish film or bloom on leaves, fruits and other plant organs. Chemically, it consists of hydrophobic organic compounds, mainly straight-chain aliphatic hydrocarbons with or without a variety of substituted functional groups. The main functions of the epicuticular wax are to decrease surface wetting and moisture loss. Other functions include reflection of ultraviolet light, assisting in the formation of an ultra-hydrophobic and self-cleaning surface and acting as an anti-climb surface.

Protection is any measure taken to guard something against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although the mechanisms for providing protection vary widely, the basic meaning of the term remains the same. This is illustrated by an explanation found in a manual on electrical wiring:

Some kind of protection is a characteristic of all life, as living things have evolved at least some protective mechanisms to counter damaging environmental phenomena, such as ultraviolet light. Biological membranes such as bark on trees and skin on animals offer protection from various threats, with skin playing a key role in protecting organisms against pathogens and excessive water loss. Additional structures like scales and hair offer further protection from the elements and from predators, with some animals having features such as spines or camouflage serving exclusively as anti-predator adaptations. Many animals supplement the protection afforded by their physiology by burrowing or otherwise adopting habitats or behaviors that insulate them from potential sources of harm. Humans originally began wearing clothing and building shelters in prehistoric times for protection from the elements. Both humans and animals are also often concerned with the protection of others, with adult animals being particularly inclined to seek to protect their young from elements of nature and from predators.

NASA's series of Great Observatories satellites are four large, powerful space-based astronomical telescopes launched between 1990 and 2003. They were built with different technology to examine specific wavelength/energy regions of the electromagnetic spectrum: gamma rays, X-rays, visible and ultraviolet light, and infrared light.

The Hubble Space Telescope (HST) primarily observes visible light and near-ultraviolet. It was launched in 1990 aboard the Space Shuttle Discovery during STS-31, but its main mirror had been ground incorrectly, resulting in spherical aberration that compromised the telescope's capabilities. The optics were corrected to their intended quality by the STS-61 servicing mission in 1993. In 1997, the STS-82 servicing mission added capability in the near-infrared range, and in 2009 the STS-125 servicing mission refurbished the telescope and extended its projected service life. It remains in active operation as of October 2024.

Biological dispersal refers to both the movement of individuals (animals, plants, fungi, bacteria, etc.) from their birth site to their breeding site ('natal dispersal') and the movement from one breeding site to another ('breeding dispersal'). The term also encompasses the movement of propagules such as seeds and spores. Technically, dispersal is defined as any movement that has the potential to lead to gene flow. The act of dispersal involves three phases: departure, transfer, and settlement. Each phase is associated with distinct fitness costs and benefits. By simply moving from one habitat patch to another, an individual's dispersal can influence not only its own fitness but also broader processes such as population dynamics, population genetics, and species distribution. Understanding dispersal and its consequences, both for evolutionary strategies at a species level and for processes at an ecosystem level, requires understanding on the type of dispersal, the dispersal range of a given species, and the dispersal mechanisms involved. Biological dispersal can be correlated to population density. The range of variations of a species' location determines the expansion range.

Biological dispersal may be contrasted with geodispersal, which refers to the mixing of previously isolated populations (or entire biotas) following the erosion of geographic barriers to dispersal or gene flow.

A blacklight, also called a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and very little visible light. One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB". This stands for "blacklight blue". A second type of lamp produces ultraviolet but does not have the filter material, so it produces more visible light and has a blue color when operating. These tubes are made for use in "bug zapper" insect traps, and are identified by the industry designation "BL". This stands for "blacklight".

Blacklight sources may be specially designed fluorescent lamps, mercury-vapor lamps, light-emitting diodes (LEDs), lasers, or incandescent lamps. In medicine, forensics, and some other scientific fields, such a light source is referred to as a Wood's lamp, named after Robert Williams Wood, who invented the original Wood's glass UV filters.

Tanning lamps (sometimes called tanning bulbs in the United States or tanning tubes in Europe) are the part of a tanning bed, booth or other tanning device which produces ultraviolet light used for indoor tanning. There are hundreds of different kinds of tanning lamps most of which can be classified in two basic groups: low pressure and high pressure. Within the industry, it is common to call high-pressure units "bulbs" and low-pressure units "lamps", although there are many exceptions and not everyone follows this example. This is likely due to the size of the unit, rather than the type. Both types require an oxygen free environment inside the lamp.

Fluorescent tanning lamps require an electrical ballast to limit the amount of current going through the lamp. While the resistance of an incandescent lamp filament inherently limits the current inside the lamp, tanning lamps do not and instead have negative resistance. They are plasma devices, like a neon sign, and will pass as much current as the external circuit will provide, even to the point of self-destruction. Thus a ballast is needed to regulate the current through them.