PHYSICS
posted by Anonymous .
1) A diffraction grating with 2.500 x 10^3 lines/cm is used to examine the sodium spectrum. Calculate the angular separation of the two closely spaced yellow lines of sodium (588.995 and 589.592) in each of the first three orders.
2) A diffraction grating has 1950 lines/cm. The angle between the first order maximum and the zerothorder maximum for monochromatic light is 27 degrees. What is the wavelength of the light?
Thanks!

n*lambda = d sin theta should get both problems.