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B As the frequency increases so does the energy Em wave carry

  1. May 10, 2016 #1
    Hi everyone,
    As we move from left to right in EM spectrum the energy EM wave carries in creases as does the Frequency. Then why even after having a lot of energy waves can't penetrate hard me trials like rock. For example, Microwave aren't that good in penetration of tough objects but have higher energy as compared to Radio waves.
  2. jcsd
  3. May 10, 2016 #2


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    When an electromagnetic radiation penetrate through a material, it doesn't necessarily have to induce bond breakage of the material's molecules. The EM radiation that can penetrate is simply not absorbed by the material. So, even a low frequency EM radiation can go through a medium which is opaque to a radiation at some higher frequency because the absorption spectrum of that medium does not have peaks around the radiation with lower frequency. A material is said to be opaque at certain frequency if it absorbs a major part of photons at that frequency. However, at some point when the intensity is very high (high photon density) like pulsed laser or focused sunlight, an opaque material can be broken in its structure due to heavy ionization or heating and the light can eventually goes through. Certainly, these two mechanisms of penetration through a material is different.
  4. May 10, 2016 #3


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    That statement is not correct - in a fundamental way. The energy of an EM wave depends on the energy radiated by the source. The difference in 'Energy' refers to the energy of the Photons involved. 1kW of blue light consists of fewer higher energy photons than 1kW of red light. (The ration is about 1:2 , in that case because the frequency of blue light is about twice the frequency of rd light.
    EnergyPhoton = hf
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