Is the Momentum of EM Radiation Influencing Electron Behavior?

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Discussion Overview

The discussion revolves around the influence of electromagnetic (EM) radiation's momentum on electron behavior and the mechanisms by which light can exert force on objects, particularly in the context of phenomena like solar sails. Participants explore the relationship between light, momentum, and the forces acting on electrons and other materials.

Discussion Character

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

Main Points Raised

  • Some participants propose that the momentum of EM radiation allows it to exert force on electrons, suggesting that this is a fundamental mechanism of interaction between light and matter.
  • Others clarify that while light possesses momentum and can push objects, the underlying mechanisms are complex and have been extensively studied in literature.
  • A participant questions how EM radiation can push objects forward, noting that the force associated with EM radiation oscillates perpendicular to its direction of travel.
  • Another participant explains that an electromagnetic wave consists of both electric and magnetic components, which are also perpendicular to the direction of travel, and introduces the Lorentz force as a relevant concept.
  • References to external resources, such as Wikipedia articles on Compton scattering and radiation pressure, are made to support claims and provide additional context.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding regarding the mechanisms of light's interaction with matter. While some agree on the basic principles of momentum transfer, there remains uncertainty and debate about the specifics of how EM radiation exerts force and the implications of this for electron behavior.

Contextual Notes

The discussion includes references to complex interactions and mechanisms that may not be fully resolved, such as the relationship between the oscillating forces of EM radiation and their effects on objects like solar sails.

k9b4
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Is the momentum of EM radiation due to the EM radiation applying a force on the electrons?
 
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Bandersnatch said:
You're probably thinking of something like this:
http://en.wikipedia.org/wiki/Compton_scattering
I don't think that's what I'm thinking of.

I mean:
Light is said to possesses momentum. That means it can push things around right? So I'm asking is the reason light can push stuff around because EM wave pushes electrons?
 
k9b4 said:
I mean:
Light is said to possesses momentum. That means it can push things around right? So I'm asking is the reason light can push stuff around because EM wave pushes electrons?

Yes, that is the basic mechanism by which light (which is electromagnetic radiation) transfers energy and momentum to objects.

But do note the word "basic" - entire books can be and have been written on the interaction of light and matter.
 
Nugatory said:
Yes, that is the basic mechanism by which light (which is electromagnetic radiation) transfers energy and momentum to objects.

But do note the word "basic" - entire books can be and have been written on the interaction of light and matter.
Thanks, basic mechanism is all I wanted.
 
Nugatory said:
Yes, that is the basic mechanism by which light (which is electromagnetic radiation) transfers energy and momentum to objects.

But do note the word "basic" - entire books can be and have been written on the interaction of light and matter.
But hold on, how does EM radiation push objects forward (such as in solar sails)? Isn't the force in EM radiation oscillating perpendicular to the direction of travel?
 
k9b4 said:
But hold on, how does EM radiation push objects forward (such as in solar sails)? Isn't the force in EM radiation oscillating perpendicular to the direction of travel?

An electromagnetic wave has both an electrical and a magnetic component. Both fields are perpendicular to the direction of travel. However, the force exerted by these fields is not in general parallel to the field direction. (google for "Lorentz force").
 
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