InterviewSolution
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InterviewSolution
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The figure, drawn here, shows the geometry of path differences for diffraction by a single slit of width a. Given appropriate reasoning to explain why the intensity of light is (i) maximum of the central point C on the screen. (ii) (nearly) zero for point P on the screen when `theta=lamda//a`. Hence, write an expression for the total linear width of the central maxima on a screen kept at a distance D from the plane of the slit. |
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Answer» At center of screen C all wavelets : (i) From slit meet in the same phase so they add constructively to produce a central maxima i.e., bright firnge. (ii) When `theta=lamda//a`, path difference from two halves of slit will be `lamda//2` i.e., wavelets from two halves reach at point P in opposite phase, giving a dark or minima. (iii) `beta_(0)=(2Dlamda)/(a)`. |
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