Reflection and refraction

what is reflection

The bouncing of light off a surface

What is the angle of incidence?

The angle between the incoming wave and the normal

What is the angle of reflection?

The angle between the reflected wave and the normal

what is the normal line

An imaginary line that's perpendicular to the surface at the point where the wave hits the surface

what is total internal reflection (TIR)?

complete reflection of a ray of light within a medium, this occurs when the angle of incidence is too big, the critical angle is the minimum angle at which TIR will occur

specular reflection

a reflection produced by a smooth surface in which parallel light rays are reflected in parallel eg. in a mirror, so the normal lines are in the same direction

diffuse reflection

Reflection that occurs when parallel rays of light hit a rough surface and all reflect at different angles

What is refraction?

when waves change direction as they pass from one medium to another

what happens when the light ray enters a denser medium in refraction

slows down and it bends towards the normal

what happens when a light ray enters a less dense medium in refraction

speeds up and bends away from the normal

what is the emergent ray

the ray of light that emerges from a medium