In a double slit experiment, if the fringe width is !!beta!! in air. If the same experiment is carried out in water the fringe width will be:
When the same experiment is conducted in water the only change compared to in air would be in the wavelength of light.
The dark and bright spots are formed due to the interference of light. If we change the wavelength the fringe width will change.
fringw width in water !!=(lambda_(water)D)/d!!
!!=1/mu (lambda_(air) D)/d!!