Bending Light in Lenses and Materials

Light changes speed when it moves through different materials. When it crosses from one material to another, it may slow down or speed up. That change in speed makes the light bend. This bending is called refraction.

Some of the light is also reflected at the boundary between the two materials. I...

Light reflects and travels at different speeds and direction, or refracts, depending on the material through which it is propagating, causing many interesting optical phenomena.

When a ray of light strikes the surface of a glass block, a part of it changes direction at the interface to return into the medium from which it originated; this ...