Physics · a topic
Total internal reflection, Taught not just answered.
A real-time, 1:1 lesson on Total internal reflection: an AI teacher explains it out loud while it visualizes every step. Interrupt it, ask why, and it checks you got it, in 26 languages.
The idea
What is Total internal reflection?
Total internal reflection is what happens when light travelling in a denser medium, such as glass or water, meets the boundary with a less dense medium at a steep enough angle and is entirely reflected back instead of passing through. As the angle of incidence grows, the refracted ray bends further from the normal until, at the critical angle, it skims along the surface; beyond that angle no refraction is possible.
Where it appears: Class 10 and 12 CBSE, GCSE and A-level, IB Physics, AP Physics 2, JEE and NEET.
Where learners get stuck
Why Total internal reflection is hard
Learners try to apply it when light goes from air into glass, where it can never happen, and they confuse the critical angle with the angle of refraction.
The picture a good explanation starts with: A ray inside a glass block hitting the top surface at three increasing angles: partly refracted, grazing along the surface at the critical angle, then fully reflected.
A lesson, step by step
How a lesson on Total internal reflection goes
01
Ask
Type or say "Why does total internal reflection only happen from denser to rarer?" in your own words, in any of 26 languages.
02
Plan
The tutor plans a storyboard, one picture per idea, starting with a ray inside a glass block hitting the top surface at three increasing angles: partly refracted, grazing along the surface at the critical angle, then fully reflected.
03
Explain
It explains Total internal reflection out loud while the picture builds step by step, pitched to your level (Class 10 and 12 CBSE and up).
04
Interrupt
Say "wait, why?" or type a doubt: it stops, answers over the picture, and carries on. Ask for a different explanation any time.
05
Check
A checkpoint question makes sure the idea landed, and Test Lab keeps the practice going.
06
Your notes
Upload a PDF or a photo of your class notes or a past paper and the lesson follows your textbook's terms.
Ask it anything
Questions learners ask about Total internal reflection
- Why does total internal reflection only happen from denser to rarer?
- How do I calculate the critical angle for water?
- How do optical fibres keep light inside?
Any of these, or your own, typed or spoken. The tutor answers on the picture and adapts to how well you are following.
Questions
Asked, Answered
Can LetMeTeach explain Total internal reflection?
Yes. Ask in your own words and the tutor plans a lesson on Total internal reflection: it starts with a ray inside a glass block hitting the top surface at three increasing angles: partly refracted, grazing along the surface at the critical angle, then fully reflected. Then it explains each step out loud as the picture builds, stops when you say "wait, why?", and ends with a checkpoint question.
Where does Total internal reflection come up?
Class 10 and 12 CBSE, GCSE and A-level, IB Physics, AP Physics 2, JEE and NEET. The lesson is pitched to your level and the exam or curriculum you follow, and you can upload your own notes or past papers so it uses your textbook's terms.
Can I learn Total internal reflection in my own language?
Yes. LetMeTeach teaches in 26 languages and plans the lesson in the language you choose rather than translating an English one, so the terms match what your textbook says. The Free plan includes 7 hours a month with no card.
Last updated
Learn Total internal reflection, Starting now.
Ask "Why does total internal reflection only happen from denser to rarer?" and watch the answer drawn. The Free plan needs no card.