In a double slit experiment, if the distance between the slits be reduced to half, then the new fringe width will be
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → doubled
In Young's double-slit experiment the fringe width is inversely proportional to the slit separation.
\( \displaystyle \beta = \frac{\lambda D}{d} \)
\( \displaystyle \beta' = \frac{\lambda D}{d/2} = 2\,\frac{\lambda D}{d} = 2\beta \)
So the fringe width is doubled.
Note: The same question was also asked in CUET (UG) 2025 on 13-05-2025 (Slot 1).