Total Internal Reflection Flashcards

All 5 cards in this deck

What is total internal reflection?

When light inside a denser medium hits the boundary at an angle of incidence greater than the critical angle, all of it is reflected back into the medium and none is refracted out.

What is the critical angle?

The angle of incidence (inside the denser medium) for which the angle of refraction is 90°.

In a ray diagram, what happens to a ray in glass that hits the glass–air boundary at exactly the critical angle?

The refracted ray travels along the boundary (angle of refraction = 90°).

True or false? Total internal reflection can happen when light travels from air into glass.

False. It only happens going from the slower, denser medium into the faster, less dense one, e.g. glass into air.

True or false? When the angle of incidence inside glass is less than the critical angle, light is refracted out of the glass at the boundary.

True. Below the critical angle most of the light refracts out, bending away from the normal.