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Physics Vocabulary
Term | Definition |
---|---|
continuous spectrum | a luminous object produces all produces all possible wavelengths of visible light. |
spectrograph | a photograph, printout, or other display of a spectrum produced by a spectroscope |
light-year | the distance light travels in a year, approximately 9.5 trillion kilometers |
intensity | a light source's power, the rate at which it radiates energy |
candela | the unit of light intensity |
inverse-square law | a situation encountered many times in physics |
incandescence | the light produced by materials heated until they glow, it occurs when atoms and electrons rapidly vibrate with thermal energy |
fluorescence | occurs when a substance radiates visible light as it absorbs a higher-energy source is removed |
phosphorescence | emit visible light after the energy source is removed, watch dials and glow-in-the-dark stickers are examples |
coherent light | extremely bright and has many uses in medicine,industry communications, and the military |
cold light | produced from chemical reactions at temperatures far below those required for incandescence |
primary hue | the basic color of light: red,yellow, orange,green |
additive primary colors | red,blue,green |
subtractive primary colors | cyan,yellow, and magenta |
complementary color | subtractive primary colors |
saturation | the brightness of a color |
value | how dark or light the color appears |
beam | made of lots of photons moving in the same direction |
ray | a line with an arrowhead showing direction |
diffuse reflection | reflection off the surface |
specular reflections | reflection off a smooth surface |
incident ray | the light ray approaches a reflective surface |
reflected ray | the outgoing ray |
law of reflection | when a light ray reflects off the surface, the angle of the incident ray, equals the angle of the incident ray |
plane mirror | a standard bathroom mirror |
virtual image | an image is seen in a position where no real objects exist |
real image | formed when the rays of light from a source are made to converge or come together by a focusing optical device |
convave mirror | the deepest point of the dished surface is the center of the mirror |
principal optical axis | an imaginary line normal to the mirror's surface at this point |
principal focus | when light rays fall on the mirror's surface, they reflect according to the law of reflection and converge on a point in the front of the mirror |
focal point | converge to a point in the center of the mirror |
focal length | the principal focus lies on the optical axis at a distance from the mirror's center |
convex mirror | a mirror that cannot produce a real image that is also bulged outward |
optical destiny | the speed of light in a material is related to the material's destiny |
index of refraction | the ratio of the speed of light in a vacuum to the speed of light in the material |
total internal refraction | if the angle of incidence is increased |
critical angle of incidence | the angle of incidence where a phenomena begins |
fiber optics | an important growing field of technology with diverse applications |
light depression | a beam of light enters a piece of glass, no matter what it's shaped, some depression takes place |
lens | a disk of optically clear material that refracts light to produce a real or virtual image |
converging lens | collects the incoming rays of light and focuses them at a point |
diverging lens | spreads the rays of light apart similar to a convex mirror |
meniscus lenses | eyeglass lenses, both sides are curved in the same direction |