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 than human eye can resolve at 500nm wavelength is :

Options

A. ' 10 mu m '
B. `100 mu m`
C. `30 mum`
D. 1 mu m`

Answer

D

Explanation

`(d_(0))/(d_(1)) = theta = (1.22 lambda)/(d)`
`d_(0) = (1.22 xx 500 xx 10^(-9))/(0.5 xx 10^(-2)) xx 25 xx 10^(-2)`
`d_(0) = 1.22 xx 25 xx 10^(-6)`
`d_(0) = 30 mum`