Interactive Tutorial about Diffraction Interactive example : Interference by two slits 

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This example simulates the interference between two waves scattered
by two slits. The incoming wave is a plane wave whose wave vector
stands normal to the grid formed by the two slits. The controls on the right allow you to enter the initial wave length, the phase of the initial wave, distance between the slits and the angle under which the diffracted waves should be displayed. The program will display an image representing the wave vectors drawn in blue and red respectively. The amplitude of each wave is plotted as a sinusoidal wave along each wave vector. The superposition of the two diffracted waves is shown as green wave. Start exploring and try to answer the questions below: Initially, keep the phase of the incoming wave at 0.5*lambda = 180 degrees = 3.14 radian. Also, for your first trials you should keep all parameters at their default values and just change the angle.

© Th. Proffen and R.B. Neder, 2003 