The speed of light in transparent medium is 0.6 times that of its speed in vacuum.what is the refractive index of the medium ?

speed of light in air  or vaccum = x (metre/sec).......say

speed of light in that medium = 0.6x  m/sec......given.

refractive index = speed of light in air  / speed of light in that medium

= x / 0.6x

= 1/0.6

= 10 / 6 = 5/3 = 1.67

hope this helps.

nice question...