Suppose a monochromatic X-ray beam of wavelength 100 pm is sent through a Young’s double slit and the interference pattern is observed on a photographic plate placed 40 cm away from the slit. What should be the separation between the slits so that the successive maxima on the screen are separated by a distance of 0.1 mm?

wavelength of mono-chromatic beam



distance of screen from the slit



Distance between successive maxima


formula relating λ, D and β, given by




here, d is the separation between the slits



Distance between separation of each slit


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