1. The problem statement, all variables and given/known data 1.compute the diffraction pattern through a ring aparture, internal radius a, external radius b, wave length lambda. the incoming wave is a monochromatic, plane wave, vertical to the ring plane. 2.how will the diffraction expression change when a->b? 3.near the aparture a narrow lens with f=10 cm' lambda=1micrometer, a=2mm, b=2.05mm. draw the intensity i the lens focus plane, according to the first computation, and themn according to the second. 2. Relevant equations fernahufer diffraction equations. 3. The attempt at a solution I did article 1 and got an electrical field with 2 bessel functions, one minus the other. I dont really know how to do 2,3.