> Initially, I expected something along the lines of the law of universal > gravitation, but I still haven't been able to find confirmation of this, > and furthermore, I found two conflicting sources, one claiming that the > relationship is inverse square, and the other that it is inverse fourth. Just to confuse, it's inverse cube ! :-) Just to confuse further http://www.conformity.com/0102reflections.html Maxwell is your friend, allthough not always a nice one. RM -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads