In dim indoor lighting a reader's pupil dilates to a diameter of mm

PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Interference and diffraction · Interference and diffraction

Optics and Photonics, Ch Fraunhofer diffraction from apertures and gratings

Problem

In dim indoor lighting a reader's pupil dilates to a diameter of 4.04.0 mm. Take the wavelength of the light as λ=550\lambda = 550 nm and use the Rayleigh criterion θmin⁡=1.22λ/D\theta_{\min} = 1.22\lambda/D. ((a)) Estimate the eye's angular resolution θmin⁡\theta_{\min}, in radians and in arcseconds. ((b)) Estimate the smallest separation between two fine print strokes that the eye can just resolve at the standard near point of 2525 cm. ((c)) A page of fine print has stroke separations of about 0.050.05 mm. Is it legible at 2525 cm under this lighting, according to your estimate?

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