does anyone know how to solve these problems->
1. A Young's double slit experiment has the screen placed 1.8 m from the double slits where the
spacing between the two slits is 0.015 mm. The angle that locates the first dark fringe above the
central maximum is 1.2. Find the wavelength of the light.
2. A thin film with an index of refraction of 1.25 is used to coat glass (see figure below). The index
of glass is 1.50. If incident light of wavelength 550 nm is minimally reflected, what is the thinnest
possible thickness of the film?
3. The second-order dark fringe in a single-slit diffraction pattern is 1.45 mm from the center of the
central maximum. The screen is 82.6 cm from a slit of width 0.835 mm. Find the wavelength of
the incident light and determine the angle at which the first-order dark fringe can be observed.