In two separate set-ups of YDSE, using light of same wavelength, fringes of equal width are observed. If ratio of slit separation in the equal width are observed. If ratio of slit separation in the two is `2:3`, the ratio of the distance between source and screen in the two set-ups is

Options

A. `2:3`
B. `3:2`
C. `4:9`
D. `9:4`

Answer

A

Explanation

`d_(1)=2d, d_(2)=3d`
`beta=(D_(1)lambda)/d_(1)=(D_(2)lambda)/d^(2)`
`D_(1)/D_(2)=d_(1)/d_(2)=2/3`