| A | B |
|---|
| photons | massless bundles of concentrated electromagnetic energy |
| light-year | the distance light travels in one year |
| electromagnetic wave | a wave that is partly electric and partly magnetic |
| electromagnetic spectrum | the range of electromagnetic waves |
| infrared | electromagnetic waves of frequencies lower then the red of visible light |
| ultraviolet | electromagnetic waves of frequencies higher than those of violet |
| transparent | to allow light to pass through |
| opaque | no light can go through |
| shadow | formed where light rays cannot reach |
| ray | thin beam of light |
| umbra | a total shadow |
| penumbra | a partial shadow, appears where some light is blocked out |
| polarization | alligning of vibrations in t.verse wave, usually by filtering out waves of other directions |
| Light has a speed of | 300,000 km/s in a vacuum, and lower avg. speeds in matter |
| Light is | energy that travels in electromagnetic waves w/in a certain range of frequencies |
| Light is produced by | vibrating electric charges in atoms |
| Light passes through | materials whose atoms absorb the energy and immed. reemit it as light |
| Light doesn't pass through | a material when the energy is changed to random kinetic energy of the atoms. |
| Light waves are transverse, so they can be | polarized (with vibrations all in the same direction) |
| Polarizing filters transmit components of | incident nonpolarized light and block components = emergence of polarized light |
