1. The problem statement, all variables and given/known data Light is normally incident on a double slit system. I'm asked to calculate the number of "orders(maxima)" visible on a screen placed in front of the slits. The light wavelength and slit separation are given. I understand that I can calculate the "order" from m=d/λ but does this number tell me the total maxima? Or am I to understand that there is a central maximum at m= 0 and then maxima at every ±m? For instance I got m=8.4; Does that mean I have 17 visible maxima or 8? Thanks! 2. Relevant equations dsinθ=mλ 3. The attempt at a solution I have calculated m but I don't quite understand it's meaning.