Science (086) — AI-generated practice question

The emergent ray is parallel to the incident ray but slightly shifted sidewards (laterally displaced).

This happens because the rectangular glass slab has two opposite parallel faces (AB and CD). The bending of light at the first surface (air to glass) and the bending at the second surface (glass to air) are equal and opposite, so the net change in direction cancels out.

Source: Chapter 9, Section 9.3.1 — Refraction through a Rectangular Glass Slab

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• Examiners expect two things: (1) the emergent ray is parallel to the incident ray, and (2) a reason — equal and opposite bending at the two parallel faces.
• Mention lateral displacement for full credit; it shows you understand the ray is not on the same line, just the same direction.
• Do not write a long derivation — this is 2 marks, so two clear points are enough.