EM Waves Penetration: Frequency Effects & Atmospheric Limitations

In summary, higher frequency EM waves are generally able to penetrate materials more easily. However, this is not always the case as it depends on factors such as reflection, multi-reflection, and absorption in the material. The specific material parameters, such as permeability, also play a role in determining the level of attenuation. It is important to note that this relationship is not always linear.
  • #1
Kyoma
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When an EM wave has a higher frequency, it is able to penetrate materials more easily.

However, why does a microwave able to penetrate haze while visible light can't? Why visible light is able to enter our atmosphere while those of gamma can't?
 
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  • #2
Kyoma said:
When an EM wave has a higher frequency, it is able to penetrate materials more easily.
This is not generally true. E.g.
http://en.wikipedia.org/wiki/File:Water_absorption_spectrum.png
 
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  • #3
First assuming TEM mode (no field component in the propagation direction).

In addition to the above poster, the attenuation of a material could be viewed upon as the sum of three things
1) Reflection, at the first boundary of the material
2) Multi-reflection, inside the material between the boundaries of the material
3) Absorption in the material itself

1) and 3) tend to increase the attenuation and 2) increase it.
1) is often just a simple function of the different wave impedances of the two regions (that is from where the wave came from and into the material we are talking about).

The absorption (3) is highly dependent on the material parameters in our "shield material".
E.g. to attenuate low frequency magnetic fields, you need a material with a high permeability value. Also all of this is of course frequency dependent, HOWEVER you cannot assume it to be linear :-)
 

FAQ: EM Waves Penetration: Frequency Effects & Atmospheric Limitations

1. How does the frequency of electromagnetic waves affect their penetration through different materials?

The higher the frequency of an electromagnetic wave, the more easily it can penetrate through materials. This is because higher frequencies have shorter wavelengths, which allows them to pass through smaller gaps and obstacles. In contrast, lower frequencies have longer wavelengths and are more easily blocked by materials.

2. What is the atmospheric limitation for the penetration of electromagnetic waves?

The Earth's atmosphere can limit the penetration of electromagnetic waves due to absorption, scattering, and reflection. Different frequencies are affected by the atmosphere in different ways. For example, high frequencies are more easily absorbed by the atmosphere, while low frequencies are more prone to scattering and reflection.

3. How do different materials affect the penetration of electromagnetic waves?

The ability of materials to allow electromagnetic waves to pass through them is largely dependent on their physical properties. Materials with high electrical conductivity, such as metals, tend to reflect or absorb electromagnetic waves. On the other hand, materials with lower conductivity, such as plastics or glass, allow electromagnetic waves to pass through with less obstruction.

4. Can electromagnetic waves penetrate through all materials?

No, not all materials are penetrable by electromagnetic waves. The ability of a material to allow electromagnetic waves to pass through depends on its physical properties, such as electrical conductivity and density. For example, dense materials like lead can block most electromagnetic waves, while materials with low density, such as air, allow them to pass through more easily.

5. How does the power of an electromagnetic wave affect its penetration capabilities?

The power of an electromagnetic wave, which is determined by its amplitude, affects its ability to penetrate through materials. Higher power waves, with higher amplitudes, can penetrate through more materials and obstacles, while lower power waves may be blocked or absorbed more easily. This is why high power electromagnetic waves, such as X-rays, are used in medical imaging to penetrate through the human body and create images of internal structures.

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