00:10
00:09
00:08
00:07
00:06
00:05
00:04
00:03
00:02
00:01
| the time required for one half the atoms of a given amount of a radioactive substance to disintegrate |
| the direct effect that one kind of particle has on another in inducing the emission or absorption of one particle by another |
| Hertzian wave | |
| —n | |
| an electromagnetic wave with a frequency in the range from about 3 × 1010 hertz to about 1.5 × 105 hertz | |
| [C19: named after H. R. | |