Absorption and reflectance spectrums

In summary, absorption and emissions spectra are related in that for a particular substance, they are the same and depend on the temperature of the medium. The light coming through can either be absorbed, reflected, or transmitted, with these three components adding up to 100%. For opaque objects, transmission is equal to 0.
  • #1
hechnal
2
0
hey,

just wondering, what's the relationship between absorption and emissions spectra (i.e. would they absorb and reflect the same wavelengths or complement wavelengths of radiation?)

thanx,

hechnal
 
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  • #2
Light that strikes an object is either:
1. Absorbed
2. Reflected
or
3. Transmitted

These must all add up to 100%:

A + R + T = 100%

For opaque objects, T=0 (no transmission) and the equation simplifies somewhat.
 
  • #3
hechnal said:
hey,

just wondering, what's the relationship between absorption and emissions spectra (i.e. would they absorb and reflect the same wavelengths or complement wavelengths of radiation?)

thanx,

hechnal
For a particular substance, they are the same. It depends on the temperature of the medium relative to the light coming through. Hotter leads to emission, colder leads to absorption.
 

FAQ: Absorption and reflectance spectrums

What is an absorption spectrum?

An absorption spectrum is a graph that shows the amount of light absorbed by a substance at various wavelengths. It is created by passing light through a sample of the substance and measuring the intensity of light that passes through it.

How is an absorption spectrum different from a reflectance spectrum?

An absorption spectrum shows the amount of light that is absorbed by a substance, while a reflectance spectrum shows the amount of light that is reflected by a substance. In other words, an absorption spectrum measures the light that is not transmitted through the substance, while a reflectance spectrum measures the light that is not absorbed by the substance.

What factors can affect the shape of an absorption spectrum?

The shape of an absorption spectrum can be affected by the chemical composition of the substance, the concentration of the substance, and the physical state of the substance (such as solid, liquid, or gas). Additionally, environmental factors such as temperature and pressure can also impact the shape of an absorption spectrum.

How is an absorption spectrum used in scientific research?

Absorption spectrums are used in a variety of scientific fields, including chemistry, physics, and astronomy. They can provide information about the chemical composition of a substance, help identify unknown substances, and aid in the study of energy levels and electronic transitions in atoms and molecules.

Can an absorption spectrum be used to determine the concentration of a substance in a sample?

Yes, an absorption spectrum can be used to determine the concentration of a substance in a sample. The amount of light absorbed by a substance is directly proportional to its concentration, so by measuring the intensity of light on the absorption spectrum, the concentration of the substance can be calculated.

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