Question

A pattern of fringes is produced when monochromatic light passes through a pair of thin slits. Would such a pattern be produce by three thin parallel slits? By thousands of such slits? Give an example to support your answer.

Answer 1

In a single slit experiment, the fringes are not equally spaced and aren’t of equal widths—the central maximum is the widest, the secondary maxima grow narrower and narrower outward, and the minima grow wider and wider outward.



In a double slit interference pattern, the fringes are equally spaced and of equal widths.



With a diffraction grating (lots of slits), the fringes are highly focused, with small widths and unequal spacing.