Question

Draw a labelled diagram to show the refraction of light when light travels from air into glass and then comes out to reach air?

Answer 1

Light bends towards the normal when it travels from a rarer medium to a denser medium and away from the normal when it travels from denser to rarer medium.

Complete step by step answer:
Consider an incident ray PQ be incident from air obliquely on a glass surface MN of a glass black KLMN. The angle at which the ray PR is incident on the surface MN is called the angle of incidence as is denoted by ‘i’. As the speed of light changes when the medium changes, the refracted light QR bends toward the normal inside the glass, because the density of glass is more than the density of air. The angle that the refracted ray makes with the normal is the refracted ray is called the angle of refraction and is denoted by ‘r’. The refracted ray QR is incident on the glass surface KL. However, this time the light ray passes from glass to air so it bends away from the normal on refraction. The angle of emergence is the angle the emergent ray makes with the normal at the surface KL, and is denoted by ‘e’. The angle of emergence is equal to the angle of incidence. The emergent ray RS is parallel to the direction of the incident ray. The distance between the emergent ray RS and the direction of incident ray (QT) is called the lateral displacement.

Note:
The light ray on passing from a rarer (air) to denser (glass) medium bends towards the normal, as the speed of light reduces in the denser medium. On passing from denser (glass0 to rarer (air) medium, the light ray bends away from the normal, as the speed of light increases in the rarer medium.