Light & Color
The part of the spectrum people can see.
Visible light
Light whose field directions are all the same.
Polarized light
About how fast light travels in a vacuum.
3 × 10⁸ m/s
Light changing direction so it leaves a surface.
Reflection
A mirror shaped like the inside of a sphere.
A concave mirror
All the rainbow colors combined.
White
Light whose field directions are randomly mixed.
Unpolarized light
A line of points that vibrate together.
A wavefront
Scattering of light in many directions from a rough surface.
Diffuse reflection
The point where parallel rays meet after hitting a concave mirror.
The focus
The absence of color.
Black
The line along which a filter lets light through.
Transmission axis
Every point on a wavefront acts as a source of these small waves.
Wavelets
Reflection in one well-defined direction from a smooth surface.
Specular reflection
An image formed where reflected rays actually meet.
A real image
Electromagnetic waves consist of oscillating fields of these two kinds.
Electric and magnetic
Reflected glare from a surface is polarized this way relative to the surface.
Parallel
How much light a source gives off, measured in lumens.
Luminous flux
A line drawn perpendicular to a surface.
A normal
Convex mirrors always make this kind of image.
Virtual
The pure colors that mix to make the rest of the visible spectrum.
Primary colors
Polarized sunglasses are usually made to block glare with this orientation.
Horizontal
Light on a surface falls off with distance according to this kind of law.
Inverse-square
How the angle of reflection compares with the angle of incidence.
Equal
Blurring of distant objects on a spherical mirror.
Spherical aberration