1. The problem statement, all variables and given/known data light travels through air, hits a film (n=1.3) and underneath that film is glass (n=1.5). What thickness of film would result in destructive interference The lights wavelength is 500nm. 2. Relevant equations n = c/v V = F*λ 3. The attempt at a solution I drew some diagrams, and my attempt is also on the diagram, the diagram is attached Also, I was wondering what an increase in n signifies? is it increase in density? and also, I believe a wave flips when it reflects off something with higher n? (fixed boundary) and moves as is through something with less n? (free boundary) could someone confirm this please?