Wave Optics

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In a Young's double slit experiment, each of the two slitsAandB, as shown in the figure, are oscillating about their fixed center and with a mean separation of 0.8 mm . The distancebetween the slits at timetis given byd=(0.8+0.04sin‌ωt)‌mm, whereω=0.08‌rad‌ s−1. The distance of the screen from the slits is 1 m and the wavelength of the light used to illuminate the slits is6000Å. The interference patternon the screen changes with time, while the centralbright fringe (zeroth fringe) remains fixed at pointO.