Question

The emergent ray and the incident ray, in the case of refraction through a glass slab are _____ to each other.

Answer 1

1. The incident ray after refraction from the glass slab deviates toward the normal and undergoes another refraction
2. As a result, the incident ray is parallel to the emergent ray.

Hence, the emergent ray and the incident ray, in the case of refraction through a glass slab are parallel to each other.