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Light
Vocabulary
Term | Definition |
---|---|
Electromagnetic Waves | transverse waves of changing electric and magnetic fields that do not require a medium to transport energy |
Medium | matter through which mechanical waves must travel |
Vacuum | space where no particles of matter exist |
Photons | particles of light |
Diffraction | bending of a wave as it moves around an obstacle or passes through a narrow opening |
Double Slit Experiment | demonstrates the wave nature of light via wave diffraction and interference |
Constructive Interference | when two waves combine to make a wave with a larger amplitude (bright light band) |
Destructive Interference | when two waves combine to make a wave with a smaller amplitude (dark band) |
Fringes | dimmer bands to either side of the central bright light band in a diffraction pattern |
Diffraction Pattern | bright and dark spots on a screen of constructive and destructive interference |
Amplitude | wave height; also the intensity/strength of an EM wave |
Frequency | number of waves per second (in Hz); directly related to EM wave energy |
Electromagnetic Spectrum | complete range of EM waves in order of increasing frequency from radio to gamma |
Visible Spectrum | tiny part of the electromagnetic spectrum that our eyes can see |
Color Spectrum | Red Orange Yellow Green Blue Indigo Violet (ROYGBIV) |
White Light | mixture of all the colors in the visible spectrum |
Prism | usually a piece of glass that separates white light into colors of the spectrum via refraction |
Dispersion | separation of light into different colors |
Refraction | bending of a wave as it enters a new medium at an angle; due to a change in velocity |
Primary Colors | red, green, and blue light |
Secondary Colors | yellow, magenta, and cyan |
Spectroscope | device that uses a prism or diffraction grating to separate light into its color components |
Diffraction Grating | device made of thousands of closely spaced slits through which light is passed to produce a color spectrum |
Polarization | aligning of vibrations in a transverse wave, usually by filtering out waves of other directions |
Snell's Law | n1sinθ1 = n2sinθ2 |
Angle of Incidence | angle between the incident ray and the normal line |
Angle of Refraction | angle between the refracted ray and the normal line |
Index of Refraction | measure of the amount a ray of light bends when it passes from one medium to another |
Normal Line | imaginary line drawn perpendicular to the surface of any boundary between two mediums |
Light Speed | how fast light travels in a vacuum ( 3x10^8 m/s ) |
Rod | type of cell in the eye that allows us to see intensity (light and dark) |
Cone | type of cell in the eye that allows us to see colors |
Magnitude | size or quantity (number) |