What causes reflection to occur in highly absorptive materials?

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In summary, the conversation discusses the concept of transparency and how it relates to reflection. It is clarified that transparency occurs when light does not reach the threshold frequency to energize an electron, allowing the light to pass through. The question then shifts to when reflection happens, and it is explained that reflection is a result of a phase-matched backward propagation of waves reemitted by the atoms/molecules/lattices of the object the incoming light is reflected off. The cause of reflection is also discussed, with it being determined that it is primarily due to the medium reemitting the incoming light and converting photon energy to another photon energy. It is noted that highly absorptive materials can still reflect light strongly.
  • #1
123physics321
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I'm not sure if this belongs here however some of you may know the answer to my question.
If I am correct, transparency occurs when light hits an object however the light does not reach the threshold frequency to energize an electron. Thus, the light does not get absorbed and is able to pass through.
My question is pertaining to reflection. When does reflection happen?
 
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  • #2
123physics321 said:
threshold frequency
Resonance frequency.
123physics321 said:
When does reflection happen?
Reflection as a result of a phase-matched backward propagation of the waves reemitted by the atoms/molecules/lattices of the object the incoming light is reflected off.
 
  • #3
"Reflection as a result of a phase-matched backward propagation of the waves reemitted by the atoms/molecules/lattices of the object the incoming light is reflected off."
Thanks for the answer, however I'm not sure if it completely answers what causes the light to reflect.
 
  • #4
Both reflection and refraction are caused by the medium reemitting light with the same frequency as the incident one. These secondary waves must be emitted such that the wave emitted at different locations in the medium superpose constructively, this is what is called the phase-matched condition. But the primary cause is that the medium reemit the incoming light - photon energy is converted to another photon energy. If most portion of the light is absorbed due to resonance frequency, only little will be reflected and refracted.
 
  • #5
blue_leaf77 said:
If most portion of the light is absorbed due to resonance frequency, only little will be reflected and refracted.
While that's true, I want to add that many highly absorptive materials reflect light strongly where the absorption coefficient is highest. Try to write with a coloured transparency marker on a black sheet of paper to see what I mean.
 

What is the difference between transparency and reflection?

Transparency refers to the property of a material that allows light to pass through it without significant scattering, while reflection refers to the property of a surface to bounce back light that hits it.

What causes an object to appear transparent?

An object appears transparent when it allows light to pass through it without being absorbed or scattered. This is typically due to the arrangement and properties of the material's molecules, such as in glass or water.

How does reflection occur?

Reflection occurs when light hits a smooth surface and bounces off at an equal angle to the angle at which it hit the surface. This is called the law of reflection and is responsible for the images we see in mirrors.

What is the difference between specular and diffuse reflection?

Specular reflection refers to the reflection of light from a smooth, shiny surface, such as a mirror. Diffuse reflection, on the other hand, occurs when light hits a rough or uneven surface and is scattered in all directions.

How is transparency and reflection used in everyday life?

Transparency and reflection are used in a variety of everyday objects and technologies. Examples include windows, mirrors, eyeglasses, and computer screens. They are also used in photovoltaic cells to harness solar energy, and in photography and imaging to capture and display images.

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