A normal persons pupil diameter varies from a minimum of around 2 mm to a maximu

Question

A normal persons pupil diameter varies from a minimum of around 2 mm to a maximum of around 8 mm.? What is the minimum and maximum diffraction limited angular resolution of a normal person's eye for light of wave length 600 nm? The light that falls on the retina, around 2 cm behind the pupil, is detected by photo-receptive cells. These cells are most closely spaced in a region called fovea on which the image of objects directly in front of the eye is produced by the cornea and lens. The density of the photo-receptive cells in the fovea is approximately 3 times 10^5 cells per square millimeter and the cells are approximately circular which means that they have a diameter of around 2.06 Mum.

Explanation / Answer

1.22×/D

minimum angular resolution = 1.22*600*10^-9/(8*10^-3) = 0.0000915 rad

maximum angular resolution = 1.22*600*10^-9/(2*10^-3) = 0.000366 rad

b) theta = 2.06*10^-6m/0.02m =  0.000103 rad <  0.000366 rad

Yes, maximum angular resolution is limited because of this

c) theta = separation/distance

sepration = distance*theta   

i) separation = 1m* 0.000103 = 0.000103m = 0.103 mm

ii)separation = 10m* 0.000103 = 0.00103m = 1.03 mm

iii)separation = 1km* 0.000103 = 1000*0.000103 = 0.103m = 10.3cm

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