Imagine that you are looking through a piece of square woven cloth at a point source (λ0 =...

Imagine that you are looking through a piece of square woven cloth at a point source (λ0 = 600 nm) 20m away. If you see a square arrangement of bright spots located about the point source (Fig. P. 10.41), each separated by an apparent nearest-neighbor distance of 12 cm, how close together are the strands of cloth?

Figure P.1 (Photo by E. H.)