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Chapter 30 Vocab.
| Question | Answer |
|---|---|
| Lens | A piece of glass (or other transparent material) that can blend parrallel rays of light so that they cross, or appear to cross, at a single point. |
| Converging Lens | A lens that is thickest in the middle, causing parrallel rays of light to converge to a focus. Also known as a convex lens. |
| Convex Lens | A lens that is thickest in the middle, causing parallel rays of light to converge or focus. Also known as a converging lens. |
| Diverging Lens | A lens that is thinnest in the middle and that causes parallel rays of light to diverge. Also known as a concave lens. |
| Concave Lens | A lens that is thinnest in the middle and that causes parallel rays of light to diverge. Alos known as diverging lens. |
| Principal Axis | The line joining the centers of curvature of the surfaces of a lens. |
| Focal Point | For a converging lens, the point at which a beam of light parallel to the principal axis converges. For a diverging lens, the point from which such a beam appears to come. |
| Focal Plane | A plane passing through focal point of a lens that is perpendicular to the principal axis.Converging lens,any incident parallel beam converges to a point somewhere on a focal plane.Diverging lens,such a beam comes from a point on a focal plane. |
| Focal Length | The distance between the center of a lens and either focal point. |
| Real Image | An image that is formed by converging light rays and that can be displayed on a screen. |
| Virtual Image | An image formed through reflection or refraction that can be seen by an observer but cannot be projected on a screen because light from the object does not actually come to a focus. |
| Ray Diagram | A diagram shpwing rays that can be drawn to determine the size and location of an image formed by a mirror or lens. |
| Eyepiece | Lens of a telescope closest to the eye; enlarges the real image formed by the first lens. |
| Objective Lens | In an optical device using compound lenses, the lens closest to the object observed. |
| Cornea | The transparent covering over the eyeball. |
| Iris | The colored part of the eye that surrounds the black opening through which light passes. The iris regulates the amount of light entering the eye. |
| Pupil | The opening in the eyeball through which light passes. |
| Retina | The layer of light-sensitive tissue at the back of the eye. |
| Farsighted | Term applied to a person who has trouble focusing on nearby objects because the eyeball is so short that images form behind the retina. |
| Nearsighted | Term applied to a person who can clearly see nearby objects but not clearly see distant objects. The eyeball is elongated so that images focus in front of rather than on the retina. |
| Astigmatism | A defect of the eye caused when the cornea is curved more in one direction than in another. |
| Aberration | Distortion in an image produced by a lens. |
| Fovea | The middle of the retina, which is responsible for our central sharpest vision. |
| Blind Spot | The small, circular, optically insensitive region in the retina where fibers of the optic nerve emerge from the eyeball. |
| Accommodation | The process by which the eye increases the degree to which the lens converges or diverges light. |
Created by:
MLVeir
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