Why we see images in mirrors Or… The angle of reflection is equal to the angle of incidence

Reflections What do you see when you look in a mirror or other highly reflective surface?

Reflections Why are you able to see yourself in a mirror but not a sheet of white paper? You need a VERY smooth flat surface to reflect back an almost exact image!

Reflection Normal Reflection from a plane (flat) mirror: Incident ray Reflected ray Angle of incidence Angle of reflection r i Mirror (medium)

Reflections Rough surfaces create many incident rays that scatter light because there are many angles of reflection even though the angles of incidence are the same

Smooth surfaces send reflected rays in the same direction

Paper surface magnified 830x

Smooth surfaces send reflected rays in the same direction Rough surfaces send reflected rays in many directions

Law of Reflection The angle of incidence (i) is always equal to the angle of reflection (r) The reflected ray and the incident ray are on opposite sides of the normal The incident ray, the normal and the reflected ray lie on the same plane (flat surface)

Using mirrors Two examples: 2) A car headlight 1) A periscope