PHY 114 Lecture Notes - Lecture 18: The Slits
Document Summary
Two waves are coherent if they maintain a fixed phase relationship (waves from the same source) Two waves are incoherent otherwise (waves from different sources) Constructive interference occurs when two waves are in phase. To be in phase, the points on the wave must have: Destructive interference occurs when two waves are a half cycle out of phase. To be out of phase, the points on the wave must have: Coherent waves can become out of phase if they travel different distances to the point of observation as shown here: must travel to reach point p. When both waves travel in the same medium, the interference conditions are: The extra length from the 90 degree marker to 2 represents the extra path length ( l
