For the same angle of incidence in media P,Q and R, the angles of refraction are `35^@, 25^@,15^@` respectively. In which medium will the velocity of light be minimum?

Explanation

According to Snell's law, `n = (sin i)/(sin r)` Also, `n=c/v` `:. n= (c)/(v)= (sin i)/(sin r)`
For given angle of incidence (i), v will be minimum, when angle of refraction r is minimum, which is for medium R.