1.
In a YDSE, bichromatic light of wavelengths 400nm400\,\text{nm} and 560nm560\,\text{nm} are used. The distance between the slits is 0.1mm0.1\,\text{mm} and the distance between the plane of the slits and the screen is 1m1\,\text{m}. The minimum distance between two successive regions of complete darkness is