An experimenter shines white light through an unknown aperture and observes on a distant screen a bright central region flanked by colored fringes. The central bright region is noticeably wider than the neighboring fringes, and the spacing between similar colors is uniform across the visible spectrum.
(1) Describe two qualitative differences you would expect between the patterns produced by (i) a single narrow slit, (ii) a pair of narrow slits, and (iii) a diffraction grating when each is illuminated with white light.
(2) Explain how you could use simple ruler measurements of fringe spacing on the screen to estimate the separation of two slits if the aperture were a double-slit. Specify any additional information you would need.
(3) Propose an observational test you could perform with the existing setup to decide whether the central bright region is governed primarily by single-slit diffraction or by multiple-slit interference. Describe the expected outcome of your test for each possibility.