In a Young's double slit experiment using slits of equal width, if width of one of the slits is doubled and the whole arrangement is immersed in water (μ=43), then fringe width

Change in width of slit has no effect on fringe width initially fringe width, β=λDd when the arrangement is immersed in water, β1=λ1Dd=(λ/μ)Dd=34λ0d∴ β−β1β×100%=(1−β1β)×100%=(1−34)×100%=25%