On entering into the glass medium light ray bends towards the normal that is light ray\xa0gets refracted on entering the glass medium. After getting refracted this ray now travels through the glass slab and comes out of the glass slab by refraction from the other interface boundary. Since ray\xa0goes from glass medium to air it again gets refracted and bends away from normal. The incident ray and\xa0the emergent ray are parallel to each other.It is the angle of incidence,\xa0r\xa0is the angle of refraction and\xa0e\xa0is the angle of emergence. Angle of incidence and angle of emergence are equal as emergent ray and incident ray are parallel to each other. When a light ray is incident normally to the interface of two media then there is no bending of light ray and it goes straight through the medium.