In young,s double slit experience monochromatic light, the frings pattern shifts by a certain distance on the screen when a mica sheet of refractive index 1.6 and thickness 1.964 microns is introduced in the path of one of the interfering waves. The mica sheet is then sheet is then removed and the distance between the slits and the screen is doubled. It is found that now the distance between succesive maximum (or minimum) is the same as the observed fringe-shift upon the introduction o fthe mica sheet. Calculate the wavelength of the monochromatic light used in the experiment.