Light with wavelength = 0.55m from a distant point source falls normally on the surface of a glass wedge. A fringe pattern whose neighbouring maxima

Light with wavelength λ = 0.55μm from a distant point source falls normally on the surface of a glass wedge. A fringe pattern whose neighbouring maxima on the surface of the wedge are separated by a distance Ax = 0.21 mm is observed in reflected light. Find:
(a) The angle between the wedge faces;
(b) The degree of light monochromatism (∆λ,/λ,) if the fringes disappear at a distance 1 ≈ 1.5 cm from the wedge's edge.