I spent a long time just trying to find the right equation and it was no surprise that I did not understand a variable of it. 1. The problem statement, all variables and given/known data Why is it that a tower of identical disc magnets behaves differently (is stronger than?) a single magnet. Known: NO NUMBERS Each disk is identical in every shape and form 2. Relevant equations This is the equation I found: 3. The attempt at a solution I figured that as more and more discs are attached 'L' increases, as it gets longer, however this causes the Flux density at x (Bx) to decrease. The only logical thing I got out of that is that the Residual flux density must increases as more are added. The only problem is, I don't know how much. As the magnets are identical, is the increase uniform (Br with one magnet = x, with two magnets = 2x, etc)? Exponential? Is there no change or is it the wrong equation? Thank you for your help.