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Nature of Light
Basic terms of Light for Astronomy Class
| Term | Definition |
|---|---|
| Mechanical Wave | wave that requires a medium and starts from a vibration in the medium |
| Longitudinal Wave | compressional wave energy transfers in the direction of the medium's vibration |
| Transverse Wave | energy travels perpendicular to the medium's vibration (s wave) |
| Surface Wave | combination of both longitudinal and transverse waves |
| Electromagnetic Wave | wave that does NOT require a medium and starts from a vibrating charged particle |
| Electromagnetic Radiation | emission or transmission of energy through the form of electromagnetic waves. |
| Crest | Peak of wave |
| Trough | bottom of wave |
| Wave Speed | = frequency x wavelength |
| Speed of Light | in a vacuum 3x10^8 m/s |
| frequency | number of waves per second (measured in hertz, Hz) |
| wavelength | distance from crest to crest or trough to trough |
| visible light | Light we can see (ROYGBIV) |
| radio waves | AM & FM - largest wave |
| microwaves | Cellphones |
| x-rays | bones, teeth, security |
| gamma rays | cancer treatment high energy |
| ultra violet | beyond violet - Tanning beds |
| infrared | Heat |
| emisson spectrum | light is split into a spectrum and only certain color bands are present |
| reflection | when waves bounce off something |
| refraction | bending of waves, due to a change in speed |
| diffraction | spreading of waves around corners |
| photons | tiny bundles of mass-less energy |
| emission | to give off |
| transmission | to pass through |