Question

 A diffraction grating consists of 20 slit-shaped openings of 2.0 μm width on one gap distance of 10 µm.
 The grating is illuminated by incident perpendicular to the grating flat waves monochromatic light. 
The combined interference diffraction pattern becomes observed on a screen 150 cm behind the grille.
 The distance between the fourth order interference main maxima is 74.2 cm. 
1. At what distance of the central maximum is the first bending minimum? 
2. If at the same time flat waves with a wavelength of 580 nm were in phase raids, from which order the main maxima
 would then be observed sufficiently separated turn into?
3. What should be the number of slit openings at least for λ = 609 nm from third order to see enough separation? 
4. Calculate the angular width of the third main maximum and the corresponding width on it screen for λ = 598 nm and N = 20. 
5. Calculate the angular width of the second bending maximum and the corresponding width on it screen for λ = 580 nm and N = 20.

Answer 1