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- #2

Meir Achuz

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For instance, for a wave leaving a dielectric into air, the reflected E does flip.

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Thanks clem. Do you know how to show this from the boundary conditions?

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If you change the sign of E instead of that of k, you have a wave traveling in the same direction as initially.

Clem, can you help me understand what role permittivity has to play in the direction of E? I don't know at all about it..

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Born2bwire

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Thanks clem. Do you know how to show this from the boundary conditions?

The Fresnel reflection coefficients have already done this for you.

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- #8

Meir Achuz

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In a dielectric, the magnitudes of E and B are related by B=sqrt{epsilon mu} E.

From Maxwell's equations, both E and B tangential are continuous at the interface.

This means (with mu =1) that E_1+E_1'=sqrt{epsilon}E_2

and E_1-E_1'=E_2.

Solve for the reflected E_1'.

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- #10

Born2bwire

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choosingto flip the electric field in this case.

It doesn't matter, you get the same solution.

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