Solving a problem in physics section 2 point 28 optics

Solving a problem in physics section 2 point 28 optics

28. The two plane-parallel glass plates form a wedge with an angle ? = 30 ". The space between the plates is filled with glycerine. On a wedge normal to the surface of the incident beam of monochromatic light with a wavelength ? = 500 nm. The reflected light is observed interference pattern. What is the number N of dark interference strips have 1 cm length of the wedge?

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