11_Chapter 24 HomeworkCH24 Wave Optics

# 11_Chapter 24 HomeworkCH24 Wave Optics - Wave Optics 24.17...

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Wave Optics 313 24.17 With and coating air coating lens nn > 2 coating ntm , light reflecting at the air-coating boundary experiences a phase reversal, but light reflecting from the coating-lens boundary does not. Therefore, the condition for destructive interference in the two reflected waves is > λ = where 0, 1, 2, m = For finite wavelengths, the lowest allowed value of m is m 1 = . Then, if , the wavelength associated with this lowest order destructive interference is 177.4 nm and 1.55 coating tn == () ( ) 1 2 1 coating nt 2 1.55 177.4 nm 550 nm = 24.18 Since , light reflected from both top and bottom surfaces of the oil film experiences phase reversal, resulting in zero net phase difference due to reflections. Therefore, the condition for constructive interference in reflected light is air oil water nnn << 2 n film tm m n , or 2 film n 
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## This document was uploaded on 10/20/2011.

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