Question

Find the speed of light in a transparent medium if the refractive index of the medium is 1.8

Answer 1

Refractive index = Speed of light in vaccum / Speed of light in medium
n = c / v

v = c / n
= (3 × 10^8 m/s) / 1.8
= 1.67 × 10^8 m/s

Speed of light in given transparent medium is 1.67 × 10^8 m/s

Answer 2

Refractive index:

Explanation:

• The proportion of the speed of light in a vacuum to its speed of light in a particular medium is known as refractive  index. It's dimensionless and  represented by symbol n.

                          $\bf n=\bf \frac{c}{v} ,\textrm{ }$

        where n represents the refractive index of medium,

        c represent the speed of light in air,

        and v speed of light in medium.

        $\bf \textrm {Speed of light in vacuum is } 3\times10^8 m/s$.

        Refractive index of the medium is 1.8

• Put value of Refractive index of the medium and speed of light in vacuum, to get speed of light.

        $n=\frac{c}{v}$

        $1.8=\frac{3\times10^8 m/s}{v}$

        $v=\frac{3\times10^8 }{1.8} m/s$

        $v=1.67\times10^8 m/s$

  So, speed of light in medium is    $\bf 1.67\times10^8 m/s$ .