Assuming that the human pupil has a radius of 0 . 25 cm and a comfortable viewing distance of 25 cm . The minimum separation between two point objects that the human eye can resolve for the light of wavelength 500 nm is

Step-by-step solution

By Fraunhofer diffraction through a circular aperture, θ = 1 .22 λ d d = diameter of pupil = 2 × 0.25 = 0.5   cm λ = 500   nm . The first dark ring is formed by the light diffracted from the hole at an angle θ with the axis. Viewing distance, D = 25   cm ∴ The minimum separation between 2 objects = D θ = 25 × 10 - 2 × 1.22 × 500 × 10 - 9 5 × 10 - 3   m D θ = 30 × 10 - 6   m ⇒ D θ = 30   μm .