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ultraviolet rays
Definition
Ultraviolet rays are invisible rays that come from the sun. They are also emitted by some artificial sources, such as tanning beds.
UV rays can cause sunburn, skin cancer, and other health problems. They can also damage plants and materials.
There are three types of UV rays:
- UVA rays: These rays are the longest and least harmful. They can cause skin ageing and wrinkles.
- UVB rays: These rays are shorter and more harmful. They can cause sunburn and skin cancer.
- UVC rays: These rays are the shortest and most harmful. They are blocked by the ozone layer in the atmosphere.
How can the word be used?
Ultraviolet rays are invisible to the human eye, but they can be detected by some instruments.
Different forms of the word
Noun:
- ultraviolet rays (invisible rays that have a shorter wavelength than visible light).
- ultraviolet radiation (the emission of ultraviolet rays).
- ultraviolet light (light that has a wavelength shorter than visible light).
Adjective:
- ultraviolet (of or relating to ultraviolet rays).
Etymology
The word "ultraviolet" is made up of the Latin words "ultra" (beyond) and "violet" (purple). The word "ultraviolet" was first used in the 19th century to refer to rays that were beyond the violet end of the visible spectrum.
Question
What are ultraviolet rays?