A parallel beam of monochromatic light incidents on two parallel slits 0.02 mm apart forms fringes of 0.125 cm width at a distances of 80 cm from the plane of the slits. Find the wavelength of the monochormatic light.

In a two-slit experiment using monochromatic light, fringes are observed on a screen at a distance from the slits. The screen is moved by 5 xx 10^-2 m towards the slits and the change in fringe width is found to be 3 xx 10^-5 m. The distance between the slits is 10^-3 m. Find the wavelength of the monochromatic light used.