I've been reading into diffraction grating recently, and have a few questions to ask. Firstly here is a diagram to help explain what I am on about. http://img411.imageshack.us/img411/3972/gratingey6.png [Broken] Ok, so here is a simple diagram. If I was using a sodium lamp to shine onto the grating, it would project something similar to this, just I forgot to put the gaps in. Firstly Am i correct in saying, in terms of collecting the data from this, that I would measure the angle from m=0 for each different colour, and the actual colour itself? Secondly After having taken these reading, how are they relevant to their frequency? I would use the formula [tex]n \lambda= d \sin \theta[/tex] , lamba being the frequency so that is what I am after, sin theeta is the angle that I have measured, but what would "d" and "n" represent? Thirdly What type of conclusion am I likely to draw from such results? Where would I expect higher frequencies and lower ones? And why would they be there? I hope, this is clear enough as I have trouble explaining what I actually mean! =] Thanks.