1. The problem statement, all variables and given/known data Show that the maximum intensity for a diffraction grating of N slits at the first principal maximum is N^2 times bigger than for a single slit. 2. Relevant equations I=I(0)[sin^2(NB)/sin^2(B)] where B is ([tex]\pi[/tex]dsin[tex]\phi[/tex])/[tex]\lambda[/tex] 3. The attempt at a solution I feel i understand the concepts here but this question has stumped me. I've scoured the internet, read through the relevant chapters in my two textbooks and still i can't see how this would be proven. It is just stated in my lecture notes, is it that intuitive? I really would be grateful for any help.