Plane-polarized electromagnetic waves

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SUMMARY

The discussion focuses on the analysis of a plane-polarized electromagnetic wave characterized by a magnetic field B = (1,1,0)BoCos(kz-wt), with Bo set at 0.001 Tesla. The wave propagates in the +z direction, and the average energy density is calculated to be 0.398 J/m³. For the third part of the problem, the fraction of energy passing through a polarizer at a 30-degree angle to the magnetic field is determined by the relationship between the electric field component and the polarizer's transmission axis.

PREREQUISITES
  • Understanding of electromagnetic wave propagation
  • Familiarity with Maxwell's equations
  • Knowledge of energy density in electromagnetic fields
  • Concept of polarization and its effects on wave transmission
NEXT STEPS
  • Study the derivation of energy density in electromagnetic waves using Uvpw = eoEo^2cos^2(kz-wt)
  • Learn about the effects of polarizers on electromagnetic waves, particularly at various angles
  • Explore the relationship between electric and magnetic fields in electromagnetic waves, specifically Bo = Eo/c
  • Investigate the implications of polarization in practical applications, such as optical devices
USEFUL FOR

Students and professionals in physics, particularly those studying electromagnetism, optical engineering, and anyone interested in the practical applications of polarized light.

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Homework Statement



Consider a plane-polarised electromagnetic wave in source-free vacuum, with magnetic field B = (1,1,0)BoCos(kz-wt), with Bo = 0.001 Tesla. Find
(1) the direction of propagation of the wave,
(2) average energy density carried by the wave, and
(3) the fraction of this energy which would pass through a perfect polariod sheet at normal incidence, if the angle between B and the transmission axis of the polariser is 30degrees.

Homework Equations


Uvpw = eoEo^2cos^2(kz-wt)
Bo=Eo/c
eo = 8.854x10^-12
Not really sure of any others

The Attempt at a Solution


(1)travelling in the +z direction
(2)Bo=Eo/c Eo= 10^5
<Uvpw> = eoEo^2x(average of cos^2) average cos^2 = 0.5
<Uvpw> = 0.5eoEo^2 = 0.398Jm-3

Im pretty sure the first two are right but I am stumped how to do part 3.
Thanks
 
Physics news on Phys.org
A polarizer let's the component of the electric field parallel to the transmission axis through; it blocks the perpendicular component.
 

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