Respuesta :

AL2006
The speed of light in any medium is

     (speed of light in vacuum)
divided by
     (index of refraction of the medium).

For the medium you're describing, it's

       c / 1.4  = about  0.714 c  =  214,137,470 m/s .

Speed of light in the medium = 2.14×10⁸ ms⁻1.

The refraction of a medium = 1.4

We know that speed of light in air= 3×10⁸ m/s

What is refractive index?

  The ratio of the speed of the light in air to the speed of the light in  medium  is defined as refractive index.

       Refractive index =  speed of light in air  ÷  speed of light in medium

              1.4     =      3×10⁸ ÷  speed of light in medium

      speed of light in medium =  3×10⁸  ÷  1.4

                                                 =  214285714.2857 km/s

Hence, the speed of light in that medium is =  214285714.2857 km/s

Learn more about the refractive index

https://brainly.com/question/23750645

#SPJ5