93. On the path of the parallel beam of monochromatic light (λ = 550 nm) is a round disk having a diameter of 3 mm. Monitoring is carried out at a point on the line connecting the center point of the disc and spaced apart from the screen at a distance of 1 m. Determine the width of the Fresnel zone, adjacent to the screen.

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