Question

The absolute refractive index of glass and water are 4/3 and 3/2 respectively. If the speed of light in glass is 2 multiply by 10 to the power 8 m/s , then determine the speed of light in
(a) vacuum
(b) water

Answer 1

hope it helps

Hence speed of light in vacuum is 3

$\times {10}^{8} mper \: sec$

Answer 2

you have given wrong information about the refractive index of Glass and water