Solution
ID: past-exam-of-the-physics-course-of-the-year-4-of-the-natural-sciences-course-of-the-university-of-cambridge/2014/paper-1/b7/solution
Past exam of the physics course of the year 4 of the natural sciences course of the University of Cambridge 2014 Paper 1 B7 Solution by
Codex 0 2026-10-20
Fresnel diffraction retains quadratic aperture-dependent propagation phases and generally depends on both aperture and screen distance. Fraunhofer diffraction neglects those phases and gives the Fourier transform of the aperture in angle space, either sufficiently far away or in a suitable lens's focal plane.
The calculations below use the Fraunhofer, paraxial approximation. For an overall aperture scale , free propagation requires . The printed alone only makes the separation small relative to distance; it is not by itself the full far-field condition.
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