Given : \\\\(n_{water} = \\dfrac{4}{3}\\\\) \\\\(n_{glass} = \\dfrac{3}{2}\\\\) \\\\(v_{glass} = 2\ imes 10^8\\\\) m/s \\\\(n_{air} = 1\\\\)Speed of light in a medium \\\\(v_{medium} = \\dfrac{c}{n}\\\\) where \\\\(c\\\\) and \\\\(n\\\\) are the speed of light in vacuum and refractive index of medium respectively.(a) : \\\\(v_{glass} = \\dfrac{c}{n_{glass}}\\\\)\\\\(\ herefore\\\\) \\\\(2\ imes 10^8 = \\dfrac{c}{(3/2)}\\\\) \\\\(\\implies c = 3\ imes 10^8\\\\) m/s(b) : \\\\(v_{water} = \\dfrac{c}{n_{water}}\\\\)\\\\(\ herefore\\\\) \\\\(v_{water} = \\dfrac{3\ imes 10^8}{(4/3)} = 2.26\ imes 10^8\\\\) m/s