Electromagnetic wave propagation

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When a plane electromagnetic wave propagates through a dielectric and then enters empty space, its speed increases to c, the speed of light in a vacuum. The Fresnel relations indicate that energy is conserved at the boundary, with some energy transmitted into the vacuum and some reflected back. The frequency of the wave remains constant during this transition, while the wavelength changes due to the difference in medium. This conservation of energy and the relationship between frequency and wavelength are crucial in understanding wave behavior at material boundaries. Overall, the transition from a dielectric to a vacuum highlights important principles of wave propagation and energy dynamics.
bernhard.rothenstein
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Please consider a plane wave that propagates through a dielectric with friendly properties (isotropic, non-conducting...) with speed c/n. What would happen if we remove the dielectric and the wave continues to propagate in empty space?
 
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Then speed = c.
 
e.m wave

Meir Achuz said:
Then speed = c.

Thanks. It is c but what happens from an enegetic point of view?
 
If the end of the dielectric is a flat face, use of the Fresnel relations show that energ is conserved. Some of the original energy continues, and some is reflected.
 
bernhard.rothenstein said:
Thanks. It is c but what happens from an enegetic point of view?

Interesting. Note that the frequency of the light does not change in the medium, only the wavelength. So, with E=hf...
 

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