1)An oil film on water appears brightest at the outer regions, where it is thinnest. from this information, what can you say about the index of refraction of oil relative to that of water.
2)Why two flashlights held close together do not produce an interference pattern on a distant screen?
3)If a fine wire is stretched across the path of a laser beam, is it possible to produce a diffraction pattern?
1) Since it is brightest at the outer region, constructive interference occurs there, so the index of refraction of oil would be lower than that of water. If it were larger, the two reflections would be out of phase and interfere ...
The solution explains concepts of refraction, interference and diffraction and how they are applied to oil films, flashlights and a laser beam.