How Do Metals Affect Electric Fields and EM Waves?

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Discussion Overview

The discussion revolves around the interaction of electric fields and electromagnetic (EM) waves with metal plates, exploring concepts related to electric field behavior in conductors, charge movement, and the reasons EM waves cannot penetrate metal interfaces.

Discussion Character

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

Main Points Raised

  • Some participants assert that electric fields do not penetrate conductors in static equilibrium, while others explain that electric fields can exist inside conductors when charges are allowed to move, such as in a circuit.
  • One participant describes how external electric fields can attract electrons within a metal, leading to charge separation that cancels the internal electric field, but notes that this does not necessarily cancel the field on the other side of the metal plate.
  • Another participant raises a question about why EM waves cannot pass through metal interfaces, suggesting that the electrons in metals can be easily accelerated by EM waves, leading to absorption or reflection of the waves.

Areas of Agreement / Disagreement

Participants express differing views on the behavior of electric fields in conductors and the interaction of EM waves with metals, indicating that multiple competing perspectives remain without a clear consensus.

Contextual Notes

Participants discuss the conditions under which electric fields and EM waves interact with metals, but there are unresolved aspects regarding the specifics of these interactions and the definitions of terms used.

Who May Find This Useful

This discussion may be of interest to those studying electromagnetism, electrical engineering, or physics, particularly in understanding the behavior of electric fields and EM waves in relation to conductive materials.

wasi-uz-zaman
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hi, i want to ask explanation that if in front of electric fields lines comes a metal plate, than as far i know electric field does not pass through it, but how would i expalin as electric field can exert force on free electrons.
 
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Your question does not make sense to me. It sounds like asking why you stop seeing things when you put on a blindfold.
 
wasi-uz-zaman said:
hi, i want to ask explanation that if in front of electric fields lines comes a metal plate, than as far i know electric field does not pass through it, but how would i expalin as electric field can exert force on free electrons.
There is no electric field inside a conductor in static equilibrium but once you allow the charges to move in a certain direction like creating a circuit, electric fields can exist inside conductors.

That is what I understood from your question.
 
wasi-uz-zaman said:
hi, i want to ask explanation that if in front of electric fields lines comes a metal plate, than as far i know electric field does not pass through it, but how would i expalin as electric field can exert force on free electrons.

The external electric field attracts the electrons, but they are not able to leave the metal as the positively charged ions of the metal also attract them. Upon application of the external electric field the electrons will move until the two forces are balanced out. Since this charge separation creates an electric field pointed in the opposite direction of the first and of the same magnitude, the two fields cancel each other out inside the conductor. This wouldn't necessarily mean that the field on the other side of the plate is cancelled, however. In general I don't think that's true.
 
thanks that helps , actually i am figuring out why EM waves cannot pass through metal interface.
wasi
 
wasi-uz-zaman said:
thanks that helps , actually i am figuring out why EM waves cannot pass through metal interface.
wasi

The electrons in the metal are easily accelerated under the influence of the EM wave. This makes it very easy for the metal to absorb the the wave or for the electrons to undergo a collective oscillation that tends to reflect the wave.
 

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