These flashlights are very useful in many labs and demonstrations.
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10nm to 400 nm. This is shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Long wavelength ultraviolet causes many substances to glow or fluoresce. Many practical applications of UV radiation derive from its interactions with organic molecules.
Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact. The amount of UV light produced by the Sun means that the Earth would not be able to sustain life on dry land if most of that light were not filtered out by the atmosphere. More energetic, shorter-wavelength “extreme” UV below 121 nm is absorbed before it reaches the ground. However, ultraviolet light (specifically, UVB) is also responsible for the formation of vitamin D in most land vertebrates, including humans. The UV spectrum, thus, has effects both beneficial and harmful to life.
The lower wavelength limit of human vision is conventionally 400 nm, so ultraviolet rays are invisible to humans. Insects, birds, and some mammals can see near-UV (i.e., slightly shorter wavelengths than what humans can see).
- Requires 3 AAA batteries (not included)
- Made in United States
Details:
- Longwave UV (UVA)
- Wavelength: 315–400nm
- Photon energy: 3.1–3.94 eV
