Total Internal ReflectionThe critical angle, and the technology built on it.PhysicsTotal internal reflection occurs above the criticalangle when travelling into a less dense medium.sin C = n₂/n₁ (n₁ > n₂)Glass to airC ≈ 42°n = 1.5.Water to airC ≈ 49°n = 1.33.Below CPartial refraction and reflectionTHE COMMON MISTAKEExpecting TIR going into a denser mediumOnly dense to less denseRefraction away from the normal is what allows the refracted ray to reach 90°.Going the other way it never can.Optical fibres use TIR at the core-cladding boundary. The cladding hasa slightly lower refractive index, by design.Total Internal Reflectionlearnposters.com
Total Internal Reflection — printable physical science wall chart from LearnPosters. Free vector PDF, US Letter and A4.

What’s on the Total Internal Reflection poster

The rule, 3 worked examples, and the mistake everyone makes.

Optical fibres use TIR at the core-cladding boundary. The cladding has a slightly lower refractive index, by design.

Questions about the Total Internal Reflection poster

What’s on the Total Internal Reflection poster?
The rule, 3 worked examples, and the mistake everyone makes. Total internal reflection occurs above the critical angle when travelling into a less…; sin C = n₂/n₁ (n₁ > n₂); Glass to air = C ≈ 42°; Water to air = C ≈ 49°; Below C = Partial refraction and reflection; Common mistake: Expecting TIR going into a denser medium → Only dense to less dense. Optical fibres use TIR at the core-cladding boundary. The cladding has a slightly lower refractive index, by design.
Who is the Total Internal Reflection poster for?
Total Internal Reflection belongs to the Physics section rather than to a school year, because physical science is not something one grade owns. Anyone learning waves & optics can pin it up — a beginner, a student mid-course, or someone revising years later.
When should you use the Total Internal Reflection poster?
Only from dense to less dense, and only beyond the critical angle. A wall chart earns its place by being glanceable from where the work is happening, so Total Internal Reflection belongs on the wall where that physical science work actually happens, within glancing distance, rather than filed away.
What other posters go with Total Internal Reflection?
Diffraction Gratings, The Doppler Effect and Lenses sit alongside Total Internal Reflection in the Physics section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.Diffraction GratingsThe Doppler EffectLenses
Is the Total Internal Reflection poster free to download and print?
Yes. Total Internal Reflection downloads as a free PDF with no account, no email and no watermark, like everything else in the Physics section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
What size does the Total Internal Reflection poster print at?
Total Internal Reflection is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Total Internal Reflection loses nothing.Printing guide

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