Depth of penetration of electromagnetic waves

In summary, X-rays penetrate deeper than visible light because they have higher energy. The relationship between frequency and depth of penetration into Earth's atmosphere is not clear from the graph.
  • #1
nousername
31
1
Hey everyone,

Im doing this research and reading this http://science.hq.nasa.gov/kids/imagers/ems/gamma.html" it had a diagram of the depth of penetration of different wavelengths into the eaths atmosphere...

my question is, How come x-rays penetrate deeper than visible light - what is the relationship between these two factors (frequency and depth of penetration into Earth's atmosphere)? Dont they have higher energy? So shouldn't they penetrate deeper? From examining the graph, i don't see any relationship between grequency of the wave and the depth of penetration. Could someone please explain to me the relationship between them?

Thankyou very much
 
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  • #2
Xrays are more strongly absorbed than visible light.

There are two separate main mechanisms at work. For em radiation to be absorbed it must dump its energy into something in the medium it is traveling through. Firstly em radiation is absorbed largely in proportion to the electron density (number of electrons per cubic metre) – it distorts the electrons in the material, and if it has high enough energy tears them right out of the atoms. But also another is at work. If the atoms or molecules of the material have 'resonances' ie excited energy states, close to the energy of the em radiation then the radiation will be absorbed much more strongly than in the first mechanism. For example in air both nitrogen and oxygen have resonances in the ultraviolet and so very little ultraviolet gets through the atmosphere.
These energy are at all sorts of values so there is no simple formula representing this type of absorption. There is a (complicated) formula for the first process but it is the 'resonances' which dominate.

Hope this helps
 
  • #3
nousername said:
Hey everyone,

snip...
my question is, How come x-rays penetrate deeper than visible light - what is the relationship between these two factors (frequency and depth of penetration into Earth's atmosphere)? Dont they have higher energy? So shouldn't they penetrate deeper? From examining the graph, i don't see any relationship between grequency of the wave and the depth of penetration. Could someone please explain to me the relationship between them?

Thankyou very much

They dont, if they did we would be all zapped by the Xrays. its the atmnosphere (particularly upper atmosphere) that protects us from the Xrays

Dave
 

1. What is the depth of penetration of electromagnetic waves?

The depth of penetration of electromagnetic waves refers to how far the waves can travel into a material before being absorbed or attenuated. This depth varies depending on the type of material and the frequency of the electromagnetic waves.

2. How does the depth of penetration change with different materials?

The depth of penetration is affected by the electrical properties of the material, such as conductivity and permittivity. Materials with higher conductivity and lower permittivity tend to have shallower depths of penetration, while materials with lower conductivity and higher permittivity allow for deeper penetration.

3. What is the relationship between frequency and depth of penetration?

The depth of penetration is inversely proportional to the frequency of the electromagnetic waves. This means that as the frequency increases, the depth of penetration decreases. This is because higher frequencies have shorter wavelengths, which are more easily absorbed by materials.

4. How does the depth of penetration impact the use of electromagnetic waves in different applications?

The depth of penetration is an important factor in determining the effectiveness of using electromagnetic waves in various applications. For example, in medical imaging, lower frequency waves are used to penetrate deeper into the body, while higher frequency waves are used for surface imaging. In telecommunications, the depth of penetration affects the range and quality of signal transmission.

5. Can the depth of penetration be controlled or manipulated?

The depth of penetration of electromagnetic waves is primarily determined by the properties of the material being penetrated. However, it can be influenced by changing the frequency or adjusting the angle of incidence. In some cases, special materials or coatings can also be used to alter the depth of penetration for specific applications.

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