In Young's experiment performed with light or wavelength 5500 Å what should be the separation between the two slits so that the highest order of maximum intensity in the interference pattern is 2 ? You may assume `D gt gt d.`

Explanation

`S_(2) L = d sin theta` or `Delta x = d sin theta`
For intensity at P to be maximum,
`Delta x d sin theta = n lambda`
`implies sin theta = (n lambda)/(d)`
Now, `sin theta le 1 implies (n lambda)/(d) le 1` or `n le (d)/(lambda) implies n_(max) = (d)/(lambda)`
In this problem, `n_(max) = 2 ` and `lambda = 5500 Å = 5500 xx 10^(-10) m.`
`:. d = n_(max) lambda = 2 xx 5500 xx 10_(-16) m`