Monochromatic light of wavelength lambda, such as light from a laser, is directed through two narrow parallel slits that are a distance d apart. there is a viewing screen a very long distance r away from the slits that is used to observe the interference pattern that emerges from the light shining through the slits. the distance that light travels from one slit to the screen is r1 and the distance that light travels from the other slit to the screen is r2. the central bright fringe of the interference pattern results due to a path difference, r1 – r2, of zero. what path difference is required to produce the first order bright fringe that is adjacent to the central bright fringe?