Total internal reflection — Science definition
When light in a higher-index medium strikes a boundary beyond the critical angle and is entirely reflected back, as in a fiber-optic cable.
Where it is taught
- Reflection, Refraction & Optics — Waves, Sound & Optics, Physics & Environmental Science, Grade 12
In use
Total internal reflection requires propagation from a higher-index to a lower-index medium and incidence angle greater than the critical angle.
Reflection, Refraction & Optics
Questions using total internal reflection
Problem 1
Total internal reflection can occur only when light travels…
- from air into glass
- between any two media at any angle
- from a denser to a lower-index medium beyond the critical angle
- from a less dense to a higher-index medium
Answer and explanation
from a denser to a lower-index medium beyond the critical angle
Total internal reflection requires light going from a higher-index (denser) medium toward a lower-index one, at an angle greater than the critical angle.