Question

Light passes through a rectangular glass slab and through a triangular glass prism. In what way does the direction of the two emergent beams differ and why?

Answer 1

In a rectangular glass slab, the emergent ray is parallel to the incident ray but they are not along the same line whereas in a prism the emergent ray is not parallel to the incident ray.
This is because in a glass block the two surfaces at which refraction occurs is parallel to each other.