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Physics
Physics - Semester 2 - Chapter 27 Key Terms
Term | Definition |
---|---|
Electromagnetic spectrum | The range of electromagnetic waves extending from radio waves to gamma rays |
Electromagnetic wave | A wave that is partly electric and partly magnetic and carries energy. Emitted by vibrating electric charges |
Infrared | Electromagnetic waves of frequencies lower than the red of visible light |
Light-year | The distance light travels through a vacuum during one year |
Opaque | Term applied to materials that absorb light without reemission, and consequently do not allow light through them |
Penumbra | A partial shadow that appears where light from part of the source is blocked and light from another part of the source is not blocked |
Photon | In the particle model of electromagnetic radiation, a particle that travels only at the speed of light and whose energy is related to the radiation in the wave model |
Polarization | The aligning of vibrations in a transverse wave, usually by filtering out waves of other directions |
Ray | A thin beam of light |
Shadow | A shaded region that results when light falls on an object and this cannot reach into the region on the far side of the object |
Transparent | Term applied to materials that allow light to pass through them in straight lines |
Ultraviolet | Electromagnetic waves of frequencies higher than those of violet light |
Umbra | The darker part of a shadow where all the light is blocked |