Math 5900 – Summer 2011 Lecture 4: Interference of Light Gernot Laicher University of Utah - Department of Physics & Astronomy

For small angles y min = radius of first dark ring c = diameter of hole d = distance from hole to screen

Diffraction grating d sin  n (= difference in path length) nn Whenever d sin  n = n  : All waves are in phase  (constructive interference); n = 0,1,2…. Otherwise they cancel each other (destructive interference). Different means constructive interference for different  n ! d