Ultraviolet Waves: Structure, Definition and Characteristics

A disturbance that travels through a medium is defined as a wave. This propagation is often explained using an equation. Some waves need a medium for propagation, while some do not necessarily require a medium. Ultraviolet waves are electromagnetic waves that fall in the latter category. 

Ultraviolet waves are produced by high-temperature surfaces such as the Sun. They enter the Earth’s atmosphere by travelling through space. The structure of ultraviolet waves is defined by the wavelength and frequency of the waves in the ultraviolet spectral range. The characteristics of ultraviolet waves can be determined by studying the wave velocity and the energy they carry. 

Ultraviolet Waves 

Ultra means “beyond”, while violet refers to the visible light waves with the highest frequencies in VIBGYOR. Ultraviolet refers to a wave of frequency higher than violet colour and thus a shorter wavelength. UV waves have a defined electromagnetic spectrum between 10 nm to 400 nm. 

UV waves of different ranges of wavelengths have different characteristics based on their structure. Phenomenons such as the sterilisation effect, effect on DNA, Rayleigh scattering, and oxidation upon ozone help us better understand the ultraviolet waves. 

Structure

The electromagnetic UV waves are 10 nm to 400 nm in wavelength, longer than x-rays, and shorter than visible rays. There are different ranges of ultraviolet waves, which makes them form a spectrum. The significant ranges stand in the UV-A, UV-B, and UV-C spectrum, respectively. 

• The UV-A ranges from 315 nm to 400 nm. These are long Ultraviolet waves that aren’t absorbed by the ozone while entering the atmosphere. 

• The UV-B ranges between 280 nm to 315 nm. The UV-B waves are absorbed mainly by the ozone layer.

• The UV-C lies between 200 nm to 280 nm and is short of ultraviolet waves. The ozone layer absorbs UV-C waves completely while they interact with the atmosphere. 

The classification of ultraviolet waves goes further with NUV (Near Ultraviolet; 300 nm – 400 nm), MUV (Middle Ultraviolet; 200 nm-300 nm), FUV (Far Ultraviolet; 122 nm-200 nm), EUV (Extreme Ultraviolet; 10 nm-121 nm), VUV (Vacuum ultraviolet; 100 nm-200 nm).

Characteristics

A brief study of the structure of ultraviolet waves directs toward different results, defining their characteristics. Numerous examples of ultraviolet waves have been used to elucidate the characteristics of the ultraviolet spectrum. 

The characteristics are as follows:-

1. Ultraviolet waves are electromagnetic waves.

2. In terms of frequency, Ultraviolet waves range from 10 nm to 400 nm (3×107 to 7.5×105 GHz). Ultraviolet waves have frequencies higher than visible light. 

3. Energy per photon for ultraviolet waves is about 3 eV to 124 eV. The energy defines the intensity of UV waves and differentiates between various Ultraviolet waves on the UV spectrum.

4. Ultraviolet waves carry relatively less energy than X-Rays which establishes more penetration power in x-rays. Both X-Rays and UV waves are ionising radiations, but X-Rays, being highly penetrating, can cross the tissue barrier while Ultraviolet waves stop on the skin barrier (resulting in severe harm when in contact for long).

What are some points which illustrate the significance of Ultraviolet Waves?

1. Astronomical aspect

Most high-energy UV waves are absorbed by Earth’s atmosphere. The data acquired from satellites about the radiation emitted by astronomical objects are used to study the formation of stars. Most young stars shine their light in ultraviolet wavelengths. As a result, it becomes easy to differentiate between young and old stars in a galaxy. Further, the same logic applies in recognising new and old galaxies.

2. Health 

• In wastewater treatment plants, UV rays are used for disinfection. 

• UV waves are used in treating vitiligo, a skin condition.

• Exposure to UV rays produces vitamin D in organisms. 

• Extreme exposure to ultraviolet waves can cause skin cancer, cataract, immune suppression, etc. 

3. Ozone Depletion

The atmosphere over Antarctica has been facing a severe depletion of the ozone layer because of UV rays. The Earth wouldn’t be able to manifest life due to the number of UV waves it receives if it weren’t for the atmosphere to filter out the radiation. 

4. Evolution/ Effects on DNA 

UV-B damaging DNA and killing certain organisms are a part of the overall role it plays in evolution. Ultraviolet waves act as a selective agent and a mutagen, leading to the molecular evolution of life on Earth.  

Conclusion

Ultraviolet Waves have numerous properties, which make them a crucial subject. They’re harmful and useful and strong enough to destroy DNA and impact evolution. UV waves are divided into various subtypes based on their wavelength and impact. X-Rays have a smaller wavelength than ultraviolet waves and carry more energy. The above examples of Ultraviolet waves and their structural foundation are enough to have an apt idea of the subject.