In a YDSE a parallel beam of light of wavelength 6000Å is incident on slits at angle of incidence `30^(@)`. A and B are two thin transparent films each of refractive index 1.5. thickness of A is `20.4mum`. Light coming through A and B have intensities I and 4I resepctively on the screen. Intensity at point O which is symmetric relative to the slits is 3I. The central maxima is above O.
(i). what is the maximum thickness of B to do so. Assuming thickness of B to be that found in part (i) answer the following parts.
(ii). Find fringe width, maximum intensity and minimum intensity on screen.
(iii). Dinstance of nearest minima from O
(iv) intensity at 5 cm on either side of O.