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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 |