Real life question: I work with UV light at my work, i wear polarized safety gla
ID: 2077793 • Letter: R
Question
Real life question:
I work with UV light at my work, i wear polarized safety glasses when i work with the light. As polarized glasses block out UV light, is it effective/safer to wear two UV glasses (one over the other) to block out the light? Not sure about the physics behind it and since im taking a physics class on properties of light.
//my work consists of seeing a reflection of uv light to scan a metal, with one pair of UV glasses on i see blue light still, then with two pairs, i completely see green (the color of the lens)
Explanation / Answer
Nowadays usage or working with UV laser is a usual thing in departments like research, medical, manufacturing etc. Mostly UV polarized safety glasses are made with Polycarbonate material. Polycarbonate lenses are up to 10 times more impact-resistant than plastic or glass lenses and they provide 100% protection from the UV rays.
Polarization and UV protection on polarized glasses are two different things. While UV refers to light of a wavelength of approximately 10nm to 400nm, light of any wavelength can be polarized. Glasses with a polarization filter block light, that is horizontally polarized (e.g. light reflected on water). This has no specific effect on UV-light. So polarized glasses do not generally protect against UV, they also need a filter dedicated to blocking UV-light.
Light emitted by the sun oscillates in all directions perpendicular to the direction it travels. When reflected on a surface such as a lake, it becomes polarized parallel to the surface of the lake. This means, the light only oscillates along the axis parallel to the surface in the plane perpendicular to the direction it travels. Polarized sunglasses block horizontally polarized light, in order to protect your eyes from these strong reflections. Polarization in the sky occurs when light scatters the molecules in the atmosphere.
Likewise the polarized safety glasses block horizontally polarized UV light, in this process the energy of incident UV light energy is reduced to particular energy that might be in the range of colours in visible region. Pure polycarbonate does not provide protection from UV light but the type of polycarbonate used for outside purposes including for glass lenses, has UV stabilizers added to it to protect it from the harmful rays. Without these stabilizers the material would soon turn yellow. This means you do not need any additional coating added to the lenses to increase their UV protection. The blue and green combination of your two pairs of UV glasses give a yellow colour.
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