| A | B |
|---|
| ray diagram | a diagram that shows how light rays change direction when they strike mirrors and pass through lenses |
| angle of incidence | the angle a reflected ray makes with a line perpendicular to a surface it strikes |
| angle of reflection | teh angle a reflected ray makes with a line perpendicular to a surface it strikes |
| plane mirror | a mirror with a flat surface |
| virtual image | a copy of an object formed at teh point from which light appears to be coming |
| concave mirror | a mirror that is curved inward |
| focal point | the point at which light rays parallel to the axis of a mirror or lens meet or appear to meet |
| real image | a copy of an object formed at the point where light rays actually meet |
| convex mirror | a mirror that is curved outward |
| index of refraction | the ratio of the speed of light in a vacuum to the speed of ligt in a medium |
| lens | an object made of anythin transparent material that has on or two curved surfaces that can refract light |
| concave lens | a lens that is curved inward at the center and is thickest at the outside edges |
| convex lens | a lens that si curved outward at the center and is thinnest at the outside edges |
| critical angle | the angle of incidence that produces an angle of refraction equal to 90 degrees |
| total internal relfection | the complete relflection of a light ray back into its orignal medium when the angle of incidence is greater than the critical angle of refraction |
| telescope | an optical instrument tht uses lenses to collect and focus light from distant objects |
| reflecting telescope | a telescope that uses only lenses to collect and focus light |
| refracting telescope | a telescope that uses only lenses to collect and focus light |
| camera | an optical instrument that records an image of an object |
| microscope | an optical instrument that uses lenses to provide enlarged images of very small, near objects |
| cornea | the transparent outer coating of the eye |
| pupil | the opening that allows light to enter the eye |
| iris | the colored part at the front of the eye, which expands and contracts to control the amount of light entering the eye |
| retina | the inner surface of the black of te eye |
| rods | light-sensitive neurons in the retina that detect low-intensity light and distinguish black, white, and gray |
| cones | light-sensitive neurons in the retina that detect color |
| nearsightedness | an eye condition in which distant objects are blurry |
| farsightedness | an eye condition that causes nearby objects to be blurry |
| astigmatism | an eye condition in which objects at any distance appear blurry because of the distorted shape of the cornea |
