00:10
00:09
00:08
00:07
00:06
00:05
00:04
00:03
00:02
00:01
| a quantized state in which matter may exist, having constant energy and separated from others in the series by finite quantities of energy |
| a device that produces a nearly parallel, monochromatic, coherent beam of light by exciting atoms to a higher energy level and causing them to radiate |