A person is viewing two red dots at a distance of `1000 m`. What should be the minimum distance between dots so the his eye can resolce two dots separately.
`("take" : lambda_(red) + 700 nm, "pupil dia" = 2.5 mm)`

Options

A. `45 cm`
B. `50 cm`
C. `35 cm`
D. `10 cm`

Answer

C

Explanation

`theta_(R ) gt (1.22 lamda)/(d)`
`(d)/(L) gt (1.22 lambda)/(d)`
`d gt (1.22 lambda xx L)/(d)`
`gt (1.22 xx 700 xx 10^(-9) xx 1000)/(2.5 xx 10^(-3))`
`gt (1.22 xx 7)/(25) = 35 cm`