For the same angle of incidence in media P, Q and R, the angles of refraction are 45°, 35° and 15° respectively. In which medium will the velocity of light be minimum? Give reason.

We know that n = sin i/sin r

For the same angle of incidence i, the refractive index will be maximum for the medium for which 'r ’ is minimum i.e., for the medium R.

Further, we know that n = c/v

Thus, velocity of light is maximum in a medium for which n is minimum i.e., for the medium R. Velocity of light is minimum in the medium R.