click below
click below
Normal Size Small Size show me how
ch. 27 vocab
ch.27 vocab
Question | Answer |
---|---|
photon | mass-less bundles of electromagnetic energy packaged in bundles |
light year | the distance light travels through a vacuum in one year |
electromagentic wave | a wave that is partly electric and partly magnectic and carries energy |
electromagnetic spectrum | the range of electromagnetic waves extending from radio waves to gamma rays |
infrared | electromagnetic waves of frequencies lower than the red of visible light |
ultraviolet | electromagnetic waves of frequencies lower than those of violet light |
transparent | materials that allow light to pass through them in staright lines |
opaque | materials that absorb light without reemission and do not allow light through them |
ray | a thin beam of light |
shadow | a shaded region that results when light falls on an object and can not reach into the region on the far side of the object |
umbra | the darker part of a shadow where all the light is blocked |
penumbra | a partial shadow that appears where light from part of the source is blocked and light from another source is not blocked |
polaarization | the alinging of vibrations in a transverse wave , usually by filtering out waves in other directions |