Solving a problem in physics section 18 point 50 optics

Solving a problem in physics section 18 point 50 optics

50. Dφ angular dispersion of the diffraction grating for λ = 6,68 ∙ 10-7 m in the spectrum of the first order is equal to 2,02 ∙ 105 rad / m. Find linear dispersion Dl (mm / m) and the period of the grating d, if the focal length of the lens, projecting range on the screen, f = 40cm.

Additional information:

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)