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Unformatted text preview: that are perfectly out of phase (lag or lead by odd multiples of λ/2) destructively interfere. Any other phase relationships cause partial interference. 6. For two in
phase sources separated by a distance d, the angle θ that describes the location of bright fringes (constructive interference) and dark fringes on a distance screen is given by: Constructive: dsinθ = mλ where m = 0, ±1, ±2, … Destructive: dsinθ = (m – ½)λ where m = ±1, ±2, … 7. The index of refraction n is a measure of how much slower an electromagnetic wave travels in a medium other than vacuum: n = c/v. Inside of any medium, the frequency of the wave does not change but the wavelength shortens to λ0/n, where λ0 is the wave’s “vacuum wavelength.” 8. When reflecting off a lower index of refraction, a wave undergoes no phase change. When reflecting off a higher index of refraction, a wave undergoes a 180° phase change, equivalent to a path length shift (or difference) of λ/2. A wave does...
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This document was uploaded on 03/26/2014.
 Spring '14

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