phys_Optics

electromagnetic spectrum

range of electromagnetic radiation

ray model of light

symbolizes light rays as geometric rays

images

occur when light rays have changede direction while traeling to us, causing us to see things that aren't really there

real images

light rays that make up the image CONVERGE

virtual images

light rays that make up the image DIVERGE

reflection

when light (or any wave) bounces off of the boundary of a new material

specular reflection

when light bounces off a smooth surface, so that all of the incoming light at a certain angle bounces off at the same angle

diffuse reflection

occures when light bounces off of a rough or textured surface, so that incoming light at a certaiun angle bounces off at many different outgoing angles and is scattered

angle of incidence

angle made by light ray and normal of surface

angle of reflection

angle outgoing light makes with normal of surface

plane mirror

mirror with flat surface

spherical mirror

mirror shaped like part of a sphere

center of curvature

pont where center of sphere would be if mirror were a complete sphere

radius of curvature

radius the mirror would have if it were a complete mirror

focal point

point at whihc incoming parallel light rays converge or the point from which they diverge

focal length

distance from the mirror to the focal point

spherical aberration

b/c not all light rays converge at a single point for spherical mirrors, it creates a blurred image

principle rays

three particular light rays that are easy to identify and draw on diagrams

1) in parallel, out thru focal point
2) in thru focal point, out parallel
3) in and out thru center

concave mirrors

light hits the inside of the sphere (into the cave)

convex mirrors

light hits the outside of a sphere

refraction

light (or any wave) is transmitted into a new material

index of refraction

ratio of the speed of light in a vacuum to the speed of light in that material

critical angle

angle of incidence less than 90 degrees which produces a refracted angle of 90 degrees

total internal reflection

for angles of incidence greater than critical angle, the reflected wave is sent back into original material

converging lenses

lenses that make light rays converge

divergine lenses

make light rays diverge

dispersion

spreading out of light into component wavelengths

polorization

a process off blocking out all light rays except those with an electric field aligned in a particular way

scattering

when light is absorbed and re radiated by particles

additive color wheel

light rays combine to make white

subtractive color wheel

pigments (like paint) combine to create black