Consider the Michelson$$s interferometer. $($a$)$ Briefly draw and explain about the Michelson$$s interferometer. $($b$)$ A thin film with index of refraction n $=1\mathrm{.}6$ is inserted on one of the arms. The f ilm is inserted perpendicularly to the path of the beam. If the wavelength of the beam is $450$nm and the pattern is shifted for $914$ fringes, evaluate the thickness of the film. $($c$)$ How much is the adjustment of the distance between the beam splitter and the mirror on one arm to make the same number of shifts on the $($b$)?$