Question

How many lenses are used in Fresnel diffraction?

Answer 1

Explanation:

Fresnel diffraction: The term "Fresnel diffraction" refers to a diffraction phenomenon in which a source and an observation point, or both, are positioned at a finite distance from an object, preventing the incident or exit wave from being considered a plane wave.

1. There are no lenses in Fresnel diffraction. The incident and diffracted wavefronts are both spherical or cylindrical in the Fresnel diffraction.
2. The slit or obstacle that causes diffraction is separated from the source and the screen by a predetermined distance.