Light of wavelength 550nm is incident on two slits 0.25mm apart, and the resulting interference pattern is observed on a screen 2.0m away. A rectangular window of width 30mm is cut symmetrically about the central maximum (from −15mm to +15mm).
(i) Calculate the total number of complete bright fringes visible within the window.
(ii) Calculate the total number of complete dark fringes visible within the same window.