In Young's double-slit experiment, the fringe width is `0.15 mm` when the source of light is of `4000 Å` wave-length. Calculate the fringe width when the source is replaced by `6000 Å`wavelength.

In Yong's double-slit experiment, the fringe width is 0.1 mm when light of wavelength 600 nm is used. Calculate the fringe width when the entire appartus is immersed in a medium of refractive index 4/3 by keeping the source of light in air.

In Young's experiment fringe width is 2 mm for light of wavelength 6000 overset(@)(A) . Calculate the fringe width if the entire apparatus is immersed in water of refractive idex 4/3.