Question

assuming that the resolving power of the eye is determined by diffraction effects only, calculate the maximum distance at which two objects separated by a distance of 2 m can be resolved by the eye. (assume pupil diameter to be 2 mm and λ = 6000 å.)

Answer 1

$\lambda l=\frac{sd}2,$

$l=\frac{sd}{2\lambda}=3.3~km.$