Geometrical Optics: Refraction, TIR & Prisms
Snell’s law of refraction, total internal reflection, critical angle, optical fibers, real and apparent depth, refraction through prisms, and the angle of minimum deviation.
Marking a lesson complete represents finishing your study of the topic; it does not denote tested mastery.
Learning Objectives
- Apply Snell’s law to calculate critical angles and solve total internal reflection boundary problems.
- Determine prism refractive index from the angle of minimum deviation: n = sin((A + Dm)/2) / sin(A/2).
Core Theory & Concepts
Geometrical optics treats light propagation using rays perpendicular to wave fronts. When light passes across a boundary between media of different optical densities, it bends according to Snell’s law. At angles beyond the critical angle in an optically denser medium, total internal reflection traps the light completely.
Prism Refractive Index Formula
At the symmetric minimum deviation condition: n = sin((A + Dm) / 2) / sin(A / 2).
Common Misconceptions
Thinking total internal reflection can happen when light goes from air into water.
Syllabus Topic Outline
- 1Snell’s law: n₁ sin θ₁ = n₂ sin θ₂ and refractive index
- 2Total internal reflection, critical angle sin c = 1/n, and fiber optics
- 3Prism refraction and minimum deviation formula