Question

(i) Write relationship between the angle of incidence and the angle of refraction for a given pair of media.
(ii) When a ray of light enters from one medium to another having different optical densities it bends. Why does this phenomenon occur?
(iii) Write one condition where it does not bend when entering a medium of different optical density.

Answer 1

(i) The ratio of the sine of angle of incidence '$i$' to the sine of angle of refraction '$r$' is constant for the given pair of media. This constant is called the refractive index.
$\mu =\frac{sini}{sinr}$
(ii) It occurs due to change in speed of light as it enters from one medium to other medium having different optical density.
(iii) When a ray of light is incident normally on the surface of second medium, it passes undeviated.