Refractive index of a medium is `mu`. Its thickness is t. Velocity of light in vacuum is e. In what time does light travel through the medium? 

Options

A. `c//mu t`
B. `mu//c t`
C. `mt// c`
D. `c t//mu`

Answer

A

Explanation

`""_(a)mu_(m) = (v_(a))/(v_(m)) rArr mu = (c)/(v_(m)) " "therefore` Velocity of light in medium `v_(m) = (c )/(mu)`
Thickness = Distance = t `therefore` Time `= ("Distance")/("Velocity") = (t)/(c//mu) = (mu t)/(c) therefore` Time = `(mu t)/(c)`