Oblique incidence for Electromagnetic Waves

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SUMMARY

The discussion centers on the representation of electric fields in diagrams for oblique incidence of electromagnetic waves. Participants clarify that while the electric field (E) can be drawn in two directions relative to the wave vector (k), consistency is crucial throughout the analysis. Reference to Griffiths' textbook highlights the importance of aligning the magnetic field (B) with the cross product of k and E. The conclusion emphasizes that any negative sign in calculations indicates a reversal of the initially assumed direction of E.

PREREQUISITES
  • Understanding of electromagnetic wave propagation
  • Familiarity with vector notation and cross products
  • Knowledge of polarization concepts in electromagnetism
  • Basic comprehension of diagrams in physics, particularly in optics
NEXT STEPS
  • Study the principles of electromagnetic wave polarization
  • Review vector calculus, focusing on cross products in physics
  • Examine Griffiths' "Introduction to Electrodynamics" for detailed examples
  • Explore the implications of negative vectors in wave equations
USEFUL FOR

Students and professionals in physics, particularly those studying electromagnetism, optics, or wave mechanics, will benefit from this discussion.

barnflakes
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I'm a bit confused, when drawing the diagram for oblique incidence, how do I choose which way to draw the electric field? For example, I know the direction of the wave is in the plane of incidence and the wave vectors are simply arrows in the direction of the wave that I draw - and that the E field is polarised parallel to the plane, but that gives two directions for which I can choose E - how do I know which one? Does it just not make a difference when all is worked out in the end?
 
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Since E oscillates, you can choose either direction for the incident E arrow in your diagram, but you have to be consistent.
 
clem said:
Since E oscillates, you can choose either direction for the incident E arrow in your diagram, but you have to be consistent.

Thank you clem, however just looking at Griffiths book he has chosen two of the E fields to point to the right of the k vector and one to the left, that's not consistent?
 
I meant consistent with that you put the B vector as kXE. If the algebra gives you a negative E, that just means it points opposite to your assumed direction.
 

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