Question

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

• A. $30\, \mu m$
• B. $1\, \mu m$
• C. $100 \,\mu m$
• D. $300 \,\mu m$

Answer 1

Answer: (A)

$30\, \mu m$

Answer 2

$y=1.22 \frac{\lambda D}{d}=\frac{500 \times 10^{-9} \times 25 \times 10^{-2}}{2 \times 0.25 \times 10^{-2}}$
$\Rightarrow y=30 \,\mu m$