Answer & explanation
Correct answer: option 4
$ \beta = \frac{\lambda D}{d}$
$\text{ Here D is doubled and d is halved then fringe width will be quadrupled.}$
Correct answer: option 4
$ \beta = \frac{\lambda D}{d}$
$\text{ Here D is doubled and d is halved then fringe width will be quadrupled.}$