Question

Speed of light in air is 3 × 10⁸ m s^–1 and the refractive index of a medium is 1.5. Find the speed of light in the medium.

Answer 1

Given:

 Speed of light in air c = 3 x 10⁸ ms^-1
Refractive index of a medium µ = 1.5
To find : Speed of light in medium v = ?
Formula :

µ = ${\displaystyle \frac{c}{u}}$

Solution:

1.5 = ${\displaystyle 3\times \frac{10}{u}}$

${\displaystyle \mu =\frac{\text{c}}{\text{v}}}$, 1.5 = ${\displaystyle \frac{3\times {10}^8}{\text{v}}}$, v = ${\displaystyle \frac{3\times {10}^8}{1.5}}$