What is the Physical Reason for Gamma Rays Being Absorbed?

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Discussion Overview

The discussion revolves around the physical reasons for the absorption of gamma rays compared to lower frequency electromagnetic (EM) waves. Participants explore the interaction of different frequencies of EM radiation with various materials, questioning the relationship between frequency and absorption or penetration capabilities.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that high-frequency EM waves, like gamma rays, are absorbed, questioning why lower frequency waves can pass through objects.
  • Others argue that gamma rays have higher penetration capabilities in materials such as steel compared to infrared rays, suggesting a complexity in the interaction between frequency and material properties.
  • A participant challenges the notion that frequency alone determines absorption, citing examples of radio waves and x-rays that behave differently than visible light.
  • Concerns are raised about the role of the material interacting with the EM waves, indicating that both the properties of the light and the material must be considered in understanding absorption phenomena.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between frequency and absorption, with no consensus reached on the underlying physical reasons for the observed behaviors of gamma rays and other EM waves.

Contextual Notes

Some claims rely on specific definitions of frequency and material properties, and there are unresolved questions regarding the role of plasma frequency in the behavior of metals with respect to light absorption.

jaydnul
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But high frequency are absorbed, like gamma rays. I would think it would be the opposite. So what's the physical reason?
 
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Why is it that lower frequency EM waves are aloud to pass through objects, but high frequency are absorbed, like gamma rays. I would think it would be the opposite. So what's the physical reason?
I believe you'll find that gamma rays have higher penetration in, say, steel, than infrared rays.
I can stop a lot of visible light with a black sheet of paper - but this has almost no effect on high energy gammas.

Where did you get this idea from?
 


This does not seem right even if one invokes the concept of plasma frequency.Metals having plasma frequency higher than frequency of light will reflect it otherwise transmit.May be you can see feynman lectures vol. 2 ,last 1/4 part for it.
 


Radio waves (low f) pass through walls that visible light doesn't. But x-rays (high f) also pass through things visible light doesn't. So frequency isn't the determining factor here perhaps?
 


lundyjb said:
But high frequency are absorbed, like gamma rays. I would think it would be the opposite. So what's the physical reason?

But x-rays, which has a higher frequency than visible light, can penetrate through your skin/body, while visible light can't!

So now we have a contradiction to your assertion, which is something that you should have brought up (I'm assuming you are well-familiar with x-rays). So now how would you proceed in your thinking? Is this whole thing really an issue with EM wave, or is this really more of a function of the material that interacts with that EM wave? Remember, there are two parties involved here - the light and the material that it is impinging upon. You seem to have dismissed the latter.

Just because the bride wears all the fancy dress and gets all the attention doesn't mean that you can ignore the groom!

Zz.
 

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