Unformatted text preview: The Principle of Superposition & Interference Superposition Principle of Superposition Principle
When two or more waves occur When simultaneously at the same location, the resulting disturbance is the sum of all the individual disturbances. For example, the interaction of many waves which differ by a phase constant φ i is given by phase y ( x, t ) = ∑
i y m sin ( k i x − ω i t + φ i ) Types of Interference Types Constructive interference occurs when Constructive
light from sources reinforce each other using the principle of linear superposition. using Destructive interference occurs when light
from sources cancel each other using the principle of linear superposition. principle Constructive Interference Constructive
Constructive interference occurs when the Constructive path difference d2d1 is some integer multiple n of the wavelength λ , and is given by given d 2 − d 1 = nλ
where n=0, 1, 2,…. where n=0, Destructive Interference Destructive
Destructive interference occurs when the Destructive path difference d2d1 is some halfinteger multiple of the wavelength λ , and is given by by 1 d 2 − d1 = n + λ 2 where n = 0, 1, 2, 3,…. where 0, Diffraction Diffraction
The bending of a wave around an obstacle or The the edges of an opening is called diffraction. For a single slit of width D or circular aperture of single circular diameter D, the first minimum of a wave of the wavelength λ is given by λ sin θ = D or λ sin θ = 1.22 D where θ is the angular spread of the wave, respectively. respectively. ...
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 Spring '10
 Hardy
 Physics, θ

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