WEBTOP Exercise

Fresnel single slit


This module operates very much like the Fresnel Circular one.  Here's the  WEBTOP link.

1.  With the default settings, is the center of the pattern bright or dark?  Do you understand why?
2.  Move the screen around to change the intensity at the center of the pattern.  Can you predict what you should see (perhaps by using the Cornu spiral)? How far back do you have to move the screen to recover the familiar Fraunhofer diffraction pattern of a single slit?
3.  Now fix the screen and change the slit width and the wavelength, holding their ratio constant.  What happens?  Why?
4.  Now play around with all the parameters.  Can you develop some empirical rules for the behavior of the pattern?  Can you see where they come from in the mathematics?