Mirrors - Foundation of Optics

How does light travel in geometrical optics

Straight lines

Optical surfaces cause what? Name 3

Refraction, absorption, reflection

Refraction definition

When light enters a medium with different refractive index

What is absorption

Always present but ignored in ‘clear’ media

Reflection definition

Light remains in the same optical medium

“Normal” definition

A line drawn perpendicular to the mirror where the ray strikes

“Angle of incidence”

Angle between the incident ray and the normal

“Angle of reflection”

Angle between the reflected ray and the normal

Symbol for angle of incidence

i

Symbol for angle of reflection

i’

First law

The incident and reflected ray lie in one plane that is perpendicular to the surface at the point of incidence

Second law

The angle of incidence is equal to the angle of reflection

Real image definition

When light from an object is convergent the object will form a real image

Virtual image (or apparent)

When light from an object is divergent as it emerges from an optical system, an image will appear to the observer at a virtual location