An interference pattern is obtained by Young's double-slit arrangement and the fringe-width is `beta`. If the distance between the slits is halved and the distance of the screen fron the slits is made three times, the new fringe-width will be tripled

Options

A. `0.25 beta`
B. `2 beta`
C. `6 beta`
D. `8 beta`

Answer

C

Explanation

`beta=(Dlambda)/d, beta^(')=(3Dlambda)/(d//2)=(6Dlambda)d`
`beta^(')=6beta`