VISIBILITY: If we talk about it the visibility that why we can't see them, is just because of the cornea, lens and retina present in our eye. The cornea does not the light of wavelength up to 300nm visible while our eye-lens block [ 300-400]nm. However, in some cases, it is visible to humans. In the case of birds and insects, it is visible to them. They have the ability to perceive these rays. For examples, insects bumblebees can see it. Few reptiles and mammals are also included in this category.
TYPES: This UV ray has its different subtypes.
| Name | Abbreviation | Wavelength (in nm) |
| Ultraviolet A | UVA | 315-400 |
| Ultraviolet B | UVB | 280-315 |
| Ultraviolet C | UVC | 100-280 |
| Near Ultraviolet | NUV | 300-400 |
| Middle-Ultraviolet | MUV | 200-300 |
| Far-Ultraviolet | FUV | 122-200 |
| Hydrogen | H Lyman-α | 121-122 |
| Extreme Ultraviolet | EUV | 10-121 |
| Vacuum Ultraviolet | VUV | 10-200 |
How UV rays are detected or discovered?
The general meaning of "Ultraviolet" is "beyond violet". This ray was discovered in the year 1801 when the German scientists Johann Wilhelm Ritter concluded an experiment to find what is beyond the violet end of the spectrum. He observed that, the energy which he is trying to find darken the silver-chloride [AgCl2] soaked paper more quickly than violet light. He termed it as the de-oxidizing agent to emphasize the chemical reactivity and to distinguish it from "heat rays". In the 19th was termed as "chemical rays". In the year 1878, it's an effect seen of a short wavelength ray, killing a bacteria. By 1903, the rays having a wavelength of 250nm is considered dangerous. And soon in the year 1960, the effect of this radiation on DNA came to be seen.
APPLICATIONS:
Ultraviolet rays are dangerous but also it is used in different electrical appliances, just due to its ability to cause chemical reactions.
It is used for the following purposes:-
Following are the tabular details:
| Wavelength | Uses |
| 13.5 nm | Extreme Ultraviolet lithography |
| 30-200 nm | Photoionization |
| 230-365 nm | UV-Id, Barcodes |
| 230-400 nm | Optical sensors |
| 240-280 nm | disinfection, decontamination of surfaces and water |
| 200-400 nm | Forensic Analysis, drugs detection |
| 270-360 nm | Proteins analysis, DNA sequencing |
| 280-400 nm | Medical imaging of cells |
| 300-320 nm | Light therapy in medicine |
| 300-365 nm | Curing of polymers and printer inks |
| 350-30 nm | Bug zappers |
How uv rays form?
Ultraviolet radiation is produced from hot surfaces, very-hot surfaces like SUN. It is also formed by continuous excitation in a gaseous discharge tube as a discrete spectrum of wavelengths. Most of this ultraviolet radiation helps in the formation of the OZONE layer at the lower stratosphere.
Do ultraviolet light is safe ?
No, UV rays aren't safe. As we have discussed above these is the most dangerous rays, that can affect our health and even kill us. However, these rays provide Vitamin D to us, which is useful.
Few related questions to Ultraviolet rays:-
1]. Does ultraviolet rays used for RADAR?
Ans. No, uv rays is not used for Radar.
2]. Do UV rays are stronger on cloudy days?
Ans. Yes, cloudy days affect the movement of UV rays, but variably. If there is overcast skies then it will lead to a reduction in the surface Ultraviolet irradiance. If the cloud is less dense, then UV rays will be reduced to some extent.
3]. Can Ultraviolet rays pass through Glass?
Ans. As we have discussed above there are different types of UV rays, and each of these UV rays has a different[ little bit] function. Just like glass can block UVB rays to some extent, but UVA can easily penetrate into this glass. Similarly, there are different types of material from which clothes are made and these different has it own ability to persists ULTRAVIOLET RAYS.
4]. Can ultraviolet rays evaporate diamond?
Ans. Yes, the concentration of Ultraviolet rays can evaporate even diamond also found in the recent search.
5]. Can ultraviolet rays travel through a vacuum?
Ans. Yes, the extreme ultraviolet rays can travel through a vacuum.
6]. Which Ultraviolet rays cause cancer?
Ans. Basically, UVA and UVB reach the earth's surface. UVB rays is mainly responsible for the cause of cancer.
7]. DO, ultraviolet rays help in photosynthesis?
Ans. Yes, UV rays can be used for photosynthesis in some plants.
8]. Ultraviolet rays are good or bad?
Ans. UV rays have both aspects. It can cause skin cancer, cataract whereas it provides us with VITAMIN-D. But if we compare, we get to know it is more dangerous than its benefits.
9]. What is the type of wave of Ultraviolet rays?
Ans. These are the transverse waves.
