Understanding the Relationship Between Electromagnetic Radiation and Photons

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Discussion Overview

The discussion revolves around the relationship between electromagnetic radiation and photons, exploring how energy propagation can be understood in both classical and quantum contexts. Participants examine the nature of electromagnetic waves, the concept of photons, and the implications of frequency in quantum mechanics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how to reconcile the discrete nature of photons with the continuous propagation of electromagnetic waves, suggesting a lack of clarity in visualizing both concepts simultaneously.
  • Another participant proposes that photons and electromagnetic waves are different concepts, indicating that combining them into a simple model is challenging.
  • A participant mentions the Poynting vector as a method to solve a problem regarding the direction of the magnetic field in relation to the electric field of a light beam.
  • There is a discussion about the frequency of a photon, with one participant seeking clarification on its meaning in quantum mechanics and how it relates to the oscillation of electromagnetic fields.
  • One participant expresses difficulty in visualizing the connection between oscillating fields and photons, while attempting to conceptualize energy propagation as occurring in discrete packets.
  • Another participant describes the oscillation of electric and magnetic fields in classical fields and relates it to the frequency of electromagnetic waves.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the relationship between electromagnetic waves and photons, with some agreeing on the distinction between the two concepts while others remain uncertain about how to integrate them. The discussion does not reach a consensus on these points.

Contextual Notes

Participants acknowledge limitations in visualizing both classical and quantum descriptions simultaneously, and there are unresolved questions about the implications of frequency in relation to photons and electromagnetic waves.

Ezio3.1415
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1. In the theory of electromagnetism, we say light(and others with different λ) propagates through anything by the alternation of the electric and magnetic field... I am still reading things abt the theory,haven't finished yet... But some things seem not clear... It seems 'em' is saying the propagation of energy is not discrete(as I visualize it)... How do we fit photons here? I mean how do I explain the propagation of energy is discrete when I am explaining using electromagnetic wave...

2. A problem a friend gave me...
You are sending a light beam in the front direction, using a flash light. If the electric field of the light is in the up direction, what will be the direction of the magnetic field?
(A) Left (B) Right (C) Front (D) Up (E) Down
Obviously the answer's not front or down or up... left or right... give ur explanation...
 
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I mean how do I explain the propagation of energy is discrete when I am explaining using electromagnetic wave...
With quantum field theory. Photons as particles and the description as electromagnetic waves are just different concepts, and you cannot easily combine them in a simple model."2." can be solved with the Poynting vector: Right
 
Thanks for the reply... I think you are right about the 'right'... :D

I asked my sir the 1st question... He said that I couldn't completely visualize both at the same time(our limitation)... But he added the frequency of the photon and the alternation of the field was same(something like that)... I understand both are different concepts and quantum theory was introduced because the propagation of energy is not continuous... But there must be a link...

By the way,what does it mean by the frequency of a photon? What do we mean by that in quantum mechanics?
 
Both in classical fields and in quantum mechanics, you have oscillating fields associated to the electromagnetic wave, and you can look at their frequency.
 
If charged particles oscillate,then the field will too and will result in emr... I am failing to view the oscillation of field with photons...
what does it mean by the frequency of a photon?

I have sort of visualized like this that the electric field and the magnetic field is alternating each other... And thus the energy is propagating... But not continuously... in discrete packets of energy 'photons'... And as the photon is 'there' because of the alternation of fields we will say its frequency would be the frequency of alternation of fields...
What do u say about it?
 
Think of radio waves with classical fields (many photons at the same time): You can measure the electric field direction and strength as it oscillates (for example "up" -> "down" -> "up" -> ...). And the frequency is the frequency of the electromagnetic wave.
 

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