1. The problem statement, all variables and given/known data
A 513 line/mm diffraction grating is illuminated by light of wavelength 567 nm. How many diffraction orders are seen?
2. Relevant equations
3. The attempt at a solution
d*sin theta = mt
t = wavelength
m = d*sin theta/t
I don't have the angle so I just omitted it assuming it would be very small and I did...
m = d/t = 3.4 so 3 diffraction orders
Is this correct?