| critical angle | the refracted light ray that lies along the boundary of the two media |
| constructive interference | a type of interference which occurs at any location along the medium where the two interfering waves have a displacement in the same direction. |
| concave lens | THIN in the middle than at the edges |
| concave mirror | reflects light from its INWARDLY curving surface and can produce either an upright, virtual image or an inverted, real image. |
| interference fringes | the overlapping of light that creates a pattern of bright and dark bands |
| coherent light | light from 2 or more sources, whose additive superposition produces smooth wave fronts. |
| index of refraction | for a medium, is the ratio of the speed of light in a vacuum to the speed of light in that medium. |
| diffuse reflection | a scattered, fuzzy reflection produced by a rough surface. |
| candela | a unit of measure indicating the luminous intensity (candlepower) of a light source in a specific direction. |
| closed-pipe resonator | a resonating tube with one end closed to air; its resonant frequencies are odd-numbered multiples of the fundamental |
| translucent | a medium that transmits light and also can reflect a fraction of the light, but doesnt allow objects to be seen clearly through it. |
| electromagnetic wave | coupled, changing electric and magnetic field that travels through space. |
| real image | an inverted optical image thats smaller than the object and is formed by the converging of light rays. |
| polarized | the property of electromagnetic waves, such as light, that describes the direction of the electric field. |
| laser | (light amplification by stimulated emission of radiation) device that produces powerful, coherent, directional, monochromatic light that can be used to excite other atoms. |
| law of reflection | the angle of incidence is equal to the angle of reflection |
| antinode | the point with the largest displacement when two wave pulses meet. |
| wave | a disturbance that carries energy through matter or space; transfers without transferring matter. |
| doppler shift | the difference between the observed wavelength of light and actual wavelength of light based on the relative speed of the observer and the source of the light. |
| total internal reflection | occurs when light traveling from a region of a higher index of refraction to a region of a lower refraction strikes the boundary at an angle greater than the critical angle such that all light reflects back into the region of the higher index of refraction. |
| principle of superposition | states the displacement of a medium caused by two or more waves is the algebraic sum of the displacements of the individual waves. |
| trough | the low point of a wave |
| wave pulse | a single disturbance or pulse that travels through a medium |
| light | part of the electromagnetic spectrum, which ranges from radio waves to gamma rays |
| longitudinal waves | a mechanical wave in which the disturbance is in the same direction, or parallel to, the direction of wave motion. |
| wavelength | the shortest distance between points where the wave pattern form repeats itself, such as from crest to crest or from trough to trough |
| focal point | point where incident light rays that are parallel to the principle axis coverage after reflecting from the mirror |
| coherent wave | a wave with a well-defined phase. |
| chromatic aberration | a spherical lens defect in which light passing through a lens is focused at different points, causing an object viewed through a lens to seem to be ringed with color |
| convex lens | THICK at the center than at the edges |
| convex mirror | reflects light from its OUTWARDLY curving surface and produces an upright, reduced, virtual image |
| decibel | the unit of measurement for sound level; also can describe the power and intensify sound waves. |
| frequency | the number of complete oscillations that a wave makes each second |
| incidence wave | a wave that strikes a boundary between two media |
| diffraction grating | device consisting of large number's of single slits that are quite close together, different light, and form a diffraction pattern thats an overlap of single-slit diffraction patterns |
| opaque | a medium that absorbs light and reflects some light rather than transmitting it, preventing objects from being seen through it. |
| regular reflection | takes place when a parallel beam of light strikes a smooth polished surface and its reflected back as a parallel beam of light |
| refraction | the change in direction of waves at the boundary between two different media. |
| Snell's law | the product of the index of refraction of a medium and the sine of the angle of incidence equals the product of the index of refraction of a second medium and the sine of the angle of refraction |
| diffraction | the bending of light around a barrier |