Perhaps I have missed something in my notes, but I have noticed when looking at different sources that some textbooks/sites state that the fringe brightness for the young's experiment is the same for all the bright fringes. Others, say that the brightness "falls off" with angle theta. Well, which is it? And how do you calculate it, not using derivatives if possible... I'm preparing for the MCAT exam and calculus is not tested. Thanks!
Here are some pictures that I've come across either in different textbooks or websites: