What happens to the fringe width in Young's double-slit experiment when it is performed in water instead of air?

The fringe width for red colour as compared to that for violet colour is approximately (in $\times$)

In a Young's double slit experiment,the intensity of light at each slit is $I_0$. An interference pattern is observed along a direction parallel to the line $S_1 S_2$ on screen $S$. Find the minimum,maximum,and the intensity averaged over the entire screen,respectively.

Describe Young's double slit experiment.

The width of one of the two slits in a Young's double slit experiment is $4$ times that of the other slit. The ratio of the maximum to the minimum intensity in the interference pattern is: (in $: 1$)

In a Young's double-slit experiment,white light is used. The distance between the two slits is $b$ and the distance between the slits and the screen is $d$ (where $d >> b$). At the point on the screen directly in front of one of the slits,certain wavelengths are missing. Some of the missing wavelengths are: $(1) \lambda = b^2/d$,$(2) \lambda = 2b^2/d$,$(3) \lambda = b^2/3d$,$(4) \lambda = 2b^2/3d$.