Lesson: Two-Slit Interference

Light with a wavelength of 625 nm passes through a sheet in which there are two parallel narrow slits. The light from the slits is incident on a screen parallel to the sheet, where a pattern of light and dark fringes is observed. A line runs perpendicular to the surface of the sheet and the direction of the slits. The line intersects the central bright fringe of the pattern on the screen. The angle between and a line that intersects the center of the bright fringe closest to the central bright fringe is . What distance separates the slits on the sheet? Give your answer to three significant figures.

Light with a wavelength of 597 nm passes through a sheet in which there are two parallel narrow slits 7.64 μm apart. The light from the slits is incident on a screen parallel to the sheet, where a pattern of light and dark fringes is observed. A line runs perpendicular to the surface of the sheet and the direction of the slits, intersecting the central bright fringe of the pattern on the screen. Two lines, line I and line II, intersect at the position of the sheet. Line I intersects the center of the dark fringe closest to the central bright fringe and line II intersects the center of the bright fringe closest to the central bright fringe. What is the angle between line I and line II? Give your answer to three significant figures.

Which of the following formulas correctly relates the angle at which light with a wavelength emerges from a pair of narrow slits separated by a distance to the order of a bright fringe of an interference pattern produced by the light on a screen?