Question

Consider the path of a ray of light passing through a rectangular glass slab for different angles of incidence.
(i) Which one is greater: angle of incidence or angle of refraction?
(ii) What happens to the emergent angle on increasing the incident angle at air-glass interface?
(iii) State the conditions when no refraction occurs.
Explain

Answer 1

We know that angle of incidence is the angle between the incident ray and the normal lying on the reflecting surface.

Angle of refraction is the measure of angle between the normal and the refracted ray.

Overhear the light is passing through a rectangular glass slab which means the real flight travels from air to glass and in this case the angle of incidence will be greater than the angle of refraction.

i) Angle of incidence is greater than angle of refraction.

Not only this but when we try to increase the emergent angle on the incident angle then the angle of emergence also increases.

ii)Angle of emergence increases.

There can be two conditions for which no refraction would take place:

i) When the Ray of light is falling perpendicular to the refracting surface that is along the normal.

ii)And the second condition is when the refractive index of both the media are equal.

Answer 2

1.angle of incidence is greater than angle of refraction
2.angle of emergence increases
3.when the incident ray is along the normal