Final answer:
Different orientations of fringe width in interference patterns assess the difference in the intensities of consecutive bright and dark fringes. This can be used for analyzing the health of the eye's retina. The orientations used are typically 0 degrees, 45 degrees, and 90 degrees.
Step-by-step explanation:
The question 'Uses interference fringes projected onto retina - What does different orientations of fringe width assess?' refers to analyzing the interference pattern created by a light wave as a method of examining the eye's health. The different orientations, such as 0 degrees, 45 degrees, and 90 degrees, assess the difference in the intensities of consecutive bright and dark fringes. The orientation of the fringes relative to a reference axis can affect the visibility of the interference pattern on the retina, thereby allowing different aspects of the eye's optical properties to be examined.
In the context of the various information provided, it is noted that angles in interference patterns should not exceed 90 degrees as this does not make sense physically. Also, in a multiple-slit interference scenario, the angular positions of principal maxima can be calculated using the equation dsinθ = nλ, where d is the separation between the slits, λ is the wavelength of the incident light, and n is the order of the bright fringe.