Assuming human pupil to have radius of 0.25 cm and comfortable viewing distance of 25 cm , the minimum separation between the two objects that human eye can resolve at 500 nm wavelength is nearly

Step-by-step solution

Minimum resolvable separation is determined using Rayleigh's criterion, where the angular resolution = 1.22 a depends on the wavelength = 500 nm and aperture diameter a = 0.5 cm . The pupil diameter a = 0.5 10⁻² m and = 500 10⁻⁹ m yield = 1.22 (500 10⁻⁹) 0.5 10⁻² = 1.22 10⁻⁴ radians . At viewing distance D = 0.25 m , the linear separation is x = D = 0.25 (1.22 10⁻⁴) = 3.05 10⁻⁵ m . Converting to micrometers: x = 30.5 m , which corresponds to option B .