Questions about light absorption

In summary, the reason why most materials absorb EUV-region light is because of the energy matching between the photon and the difference in energy levels of the atom. This causes the atom to become excited and release energy, which results in heating up the material. Hard X-rays can go through all materials because their high energy can even ionize the atoms. However, there is a difference in absorption between atomic gases and solids. For more information, refer to the FAQ subforum in the General Physics forum.
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  • #2
It is to do with how absorption happens.

Let's see if I can give you a simple model:

A photon encounters an atom, it is absorbed if the energy of the photon matches closely enough with the difference in energy between two atomic energy levels. The atom becomes excited for a while, then releases the energy in a series of lower energy jumps or mechanically by jostling adjacent atoms ... so the material heats up.

The higher the energy of the photon, the bigger the energy hit, and for very high energy (eg x-rays or gamma rays) the energy is enough to ionize the atom. Thus even x-rays do not go through everything. In fact, x-ray absorbtion spectroscopy is an important tool.

For a wider discussion see:
https://www.physicsforums.com/showthread.php?t=317716
 
  • #3
There is a difference between absorption by atomic gasses, versus absorption by a solid. Please read the FAQ subforum in the General Physics forum, especially the discussion on "phonons".

Zz.
 

FAQ: Questions about light absorption

What is light absorption?

Light absorption is the process where light energy is absorbed by particles or materials, causing the light to be converted into other forms of energy such as heat.

How does light absorption occur?

Light absorption occurs when photons of light interact with particles or molecules in a material. These interactions cause the particles to absorb the energy of the photons, increasing their internal energy and causing them to vibrate or move faster.

What factors affect light absorption?

The factors that affect light absorption include the wavelength and intensity of the light, the properties of the material (such as its composition, thickness, and surface characteristics), and external conditions such as temperature and pressure.

Why do some materials absorb more light than others?

The ability of a material to absorb light depends on its molecular structure and composition. Some materials have specific molecular arrangements that allow them to interact more strongly with certain wavelengths of light, resulting in higher absorption rates.

How is light absorption important in various fields of science?

Light absorption plays a crucial role in various fields of science, including chemistry, biology, and environmental science. It is used to study the properties of materials, understand chemical reactions, and analyze the composition of substances. In biology, light absorption is essential for photosynthesis, the process by which plants convert light energy into chemical energy. It is also used in environmental sciences to monitor the health of ecosystems and study the effects of pollution on light absorption by plants and other living organisms.

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