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On Thu, 30 Jun 2005 13:43:13 -0500, Cecil Moore
wrote: An angle of incidence of 30 degrees is irrelevant to this particular example. Changing the question to suit the answer, Hmm? As if it mattered! How much power is reflected from Surface A (first incidence)? The reflectance is 0.01, so 1%. First incidence 0.01 watts depending upon the polarization r¬ = 1.583% and r|| = 0.5485% Splitting the difference (1.066%) 0.0107W or 0.9893W @ 24° available at the next interface How much power is reflected from Surface B (first incidence)? The reflectance is 0.01, so 1%. First incidence is 0.0099 watts depending upon the polarization r¬ = 1.3381% and r|| = 0.7099% Splitting the difference (1.024%) 0.0101W or 0.9792W @ 19° available at the next interface How much power is transmitted through all interfaces? One watt net to the "load". Already provided as 0.9792W ********************************** Since you couldn't answer the original question, let's explore how accurate your answer to your own question was: How much power is reflected from Surface A (first incidence)? The reflectance is 0.01, so 1%. First incidence 0.01 watts depending upon the polarization r¬ = 0.9999% and r|| = 0.9999% Splitting the difference (0.9999%) 0.0100W or 0.9900W @ 0° available at the next interface How much power is reflected from Surface B (first incidence)? The reflectance is 0.01, so 1%. First incidence is 0.0099 watts depending upon the polarization r¬ = 0.9998% and r|| = 0.9998% Splitting the difference (0.9998%) 0.0099W or 0.9801W @ 0° available at the next interface How much power is transmitted through all interfaces? One watt net to the "load". Already provided as 0.9801W But, hey, what's 2% error in a conservation of energy equation? You can prove anything (especially your absolute proofs) if you simply discard precision. Pons and Fleishman proved cold fusion by throwing away fewer digits than you. Well, for 1W of light and presuming cancellation (you cannot achieve full cancellation); this leaves 100µW of light reflected from a non-reflecting layer - which is quite bright. So, energy is conserved, and there is no such thing as complete cancellation. By the way, the math is available from: Hecht, Eugene, Optics, 2nd Ed, Addison Wesley, 1987 or perhaps you should invest in: Hecht, Eugene, Optics, Schaum's Outline Series, McGraw-Hill ,1975 |
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