Problem 5.83

Monochromatic light passes through an orifice in a screen \(S c\) (Fig. 5.17 ) and being reflected from a thin transparent plate \(P\) produces fringes of equal inclination on the screen. The thickness of the plate is equal to \(d,\) the distance between the plate and the screen is \(l\), the radii of the \(i \mathrm{th}\) and \(k\) th dark rings are \(r_{i}\) and \(r_{k} .\) Find the wavelength of light taking into account that \(r_{i, k} \ll l\).