Light enters a glass slab (n = 1.5) at angle i = 30°. The angle of refraction r inside glass is approximately:

**Snell:** 1 × sin 30° = 1.5 × sin r → sin r = 0.5 / 1.5 = 0.333 → r = arcsin(0.333) ≈ **19.47°**. Light bends toward the normal (denser medium).