A point source of monochromatic light with a wavelength of 480 nm is located at a distance of 6 m from the receiver. At a distance of 2 m from the source, between the receiver and the source, a screen with a round hole is placed. The screen is located on a straight line connecting the source and receiver, the center of the hole lies on this line. What should be the radius of this hole in order to fit three Fresnel zones in it?

A detailed solution with a brief record of the conditions, formulas and laws used in the solution, the derivation of the calculation formula and the answer.
If you have questions about the solution, write. I try to help.